Jose Edua r do Vi l l a r r e a l -Ba ra j a s - U of C€¦s4d 12:00 dilli raj paudyal measurement...

Jose Eduardo Villarreal-Barajas - U of C

& best posterwww.quarknova.ucalgary.ca/ WNPPC50

Friday 19:00 - 21:45

Opening Remarks and Welcome

S1 : Neutrino Physics

Chair: D. Grant (UofA)

S1

Invited19:00 N.J.T.Smith

THE STATUS OF DEEP UNDERGROUND LABORATORIES AND THE SCIENCE

PROGRAMME AT SNOLAB

S1a 19:30 K. ClarkSTUDYING LOW ENERGY ATMOSPHERIC NEUTRINOS AT THE SOUTH

POLE WITH THE PINGU DETECTOR

S1b 19:45 Sophie BerkmanMEASURING THE CHERENKOV LIGHT PRODUCED BY CHARGED PIONS IN

WATER

S1c 20:00 S. Giffin OSCILLATION RESULTS FROM THE T2K EXPERIMENT

S1d 20:15 A. KolacekeEFFECT OF THE EMISSION SPECTRA OF WLS FIBERS ON LIGHT

COLLECTION IN SCINTILLATING BARS

S1e 20:30Christine

NielsenPHYSICS MEASUREMENTS AT THE T2K NEAR DETECTOR

S2 : Nuclear Medicine / Antihydrogen

Chair: G. Ball (TRIUMF)

S2

Invited20:45

J. Eduardo

Villarreal-

Barajas

CLINICAL DOSIMETRY: EVOLUTION, STATE OF THE ART AND FUTURE

DIRECTIONS

S2a 21:15 E. HimbeaultMODELING PROTON THERAPY: A STUDY OF SECONDARY NEUTRON

EMISSIONS

S2b 21:30 Tim Friesen RESONANT QUANTUM TRANSITIONS IN ANTIHYDROGEN

Reception 21:45 - 23:15

Saturday 08:30 - 12:30

S3 : Nuclear Spectroscopy

Chair: D. Leahy (UofC)

S3

Invited08:30 M.R. Pearson LASER SPECTROSCOPY WITH EXOTIC SPECIES

S3a 09:00 A. Lennarz IN-TRAP DECAY SPECTROSCOPY AT THE TRIUMF FACILITY

S3b 09:15 A.K. Cheeseman

OPTIMISING DIGITAL SIGNAL PROCESSING ALGORITHMS FOR HIGH

RESOLUTION GAMMA-RAY SPECTROSCOPY WITH THE GRIFFIN

SPECTROMETER

S3c 09:30 U. Rizwan ACCEPTANCE TESTS OF GRIFFIN HPGe CLOVERS AT SFU

S3d 09:45 E. T. RandINVESTIGATION OF THE E2 AND E3 MATRIX ELEMENTS IN 200Hg USING

INELASTIC SCATTERING

S3e 10:00 A. Diaz VarelaSTRUCTURE STUDY OF 110CD VIA A HIGH-STATISTICS beta+/EC-DECAY

110IN MEASUREMENT

Coffee and poster viewing break / Group Photo

S4 : Measurements of Nuclear Properties

Chair: D. Hobill (UofC)

S4

Invited10:45

Stephan

EttenauerHIGH PRECISION MASS MEASUREMENTS OF RARE ISOTOPES AT TITAN

S4a 11:15 A. T. LaffoleyHIGH-PRECISION HALF-LIFE MEASUREMENTS FOR THE SUPERALLOWED

beta+ EMITTER 14O

S4b 11:30 T.D. MacdonaldEXPLORING A CALIBRATION DISCREPANCY AT SAGE & GALLEX : THE

DIRECT Q-VALUE MEASUREMENT OF 51Cr(e, nu_e)51V AT TITAN

S4c 11:45 Mark McCreaNPDGAMMA - PARITY VIOLATION IN CAPTURE OF COLD NEUTRONS ON

PROTONS

S4d 12:00 Dilli Raj Paudyal MEASUREMENT OF PROTON SPIN POLARIZABILITIES AT MAMI

S4e 12:15 C. Collicott MEASUREMENT OF THE SPIN POLARIZABILITIES OF THE PROTON

Anniversary Dinner 17:30 - 19:30

Saturday 19:30 - 22:30

S5 : The Higgs and Standard Model Physics

Chair: M. Wieser (UofC)

S5

Invited19:30 A. Canepa DISCOVERY OF A HIGGS-LIKE BOSON AT THE LHC

S5a 20:00 M. LeBlanc DIRECT STOP PRODUCTION IN BOOSTED HADRONIC FINAL STATES

S5b 20:15 Shaun KruegerTHE GLUEX EXPERIMENT: TAKING MEASUREMENTS FROM THE BARREL

CALORIMETER

S5c 20:30 Wenliang LiCHERENKOV MIRROR REFLECTIVITY MEASUREMENTS FOR HALL C AT

JEFFERSON LAB

S5d 20:45 S. MacEwanTHE QWEAK EXPERIMENT: PERFORMING THE FIRST DIRECT

MEASUREMENT OF THE WEAK CHARGE OF THE PROTON

Coffee and poster viewing break

S5e 21:30 M. van Caspel THE TOPOLOGICAL CASIMIR EFFECT

S5f 21:45 C. Cao PHYSICAL IMPLICATIONS OF THE TOPOLOGICAL CASIMIR EFFECT

S5g 22:00 D. vom Bruch THE TRIUMF PIENU EXPERIMENT

S5h 22:15Jean-Francois

Caron

A CLUSTER-COUNTING DRIFT CHAMBER FOR FLAVOUR PHYSICS

EXPERIMENTS

Sunday 08:30 - 12:30

S6 : Nuclear and High-Energy Astrophysics

Chair: R. Kruecken (TRIUMF)

S6

Invited08:30 Falk Herwig

NUCLEOSYNTHESIS, HYDRODYNAMICS AND EVOLUTION OF SINGLE

STARS, NOVA, AND WHITE DWARF MERGERS

S6a 09:00 S. PillayACCRETING WHITE DWARFS: A ONE-ZONE ANALYSIS OF NUCLEAR

BURNING

S6b 09:15 C. Akers

FIRST DIRECT MEASUREMENT OF THE 18F(p,gamma )19Ne REACTION

AND THE IMPLICATIONS FOR DETECTING 18F gamma -RAY EMISSION

FROM NOVAE

S6c 09:30 M. Kostka THE R-PROCESS NUCLEOSYNTHESIS CODE, R-JAVA 2.0

S6d 09:45 Z. ShandTHE EFFECT OF BETA-DELAYED NEUTRON EMISSION ON R-PROCESS

ELEMENTS PRODUCED IN THE HIGH ENTROPY WIND OF A SUPERNOVA

S6e 10:00 Amir OuyedNUCLEOSYNTHESIS CAUSED BY THE COLLISION OF A DETONATING

NEUTRON STAR’S EJECTA WITH THE SUPERNOVA’S EJECTA

Coffee and poster viewing break

S6f 10:45 M. Tahani GALACTIK : A CHEMICAL EVOLUTION CODE

S6g 11:00Mohammed

Hassan

COMBINED ANALYSIS OF X-RAY SPECTRA OF THE SOUTHWEST CYGNUS

LOOP DETECTED BY SUZAKU AND XMM-NEWTON OBSERVATORIES

S6h 11:15 K. GreenDISENTANGLING THE COMPLEX ENVIRONMENT OF THE GAMMA CYGNI

SUPERNOVA REMNANT

S6i 11:30 Fatima GarciaSULFUR BEARING SPECIES IN THE ORION SOUTH MOLECULAR CLOUD

REGION

S7 : Dark Matter

Chair: R. Ouyed (UofC)

S7

Invited11:45 Itay Yavin THE CASE FOR DARK MATTER AS A NEW ELEMENTARY PARTICLE

S7a 12:15 T. R. Wood DARK MATTER SEARCHES USING THE ICECUBE NEUTRINO OBSERVATORY

Prize Ceremony (15-20 min)

Posters

N. Koning DEMONSTRATION OF GALACTIK; A CHEMICAL EVOLUTION CODE

D. Leahy NEW VIEWS OF HERCULES X-1 FROM 15 YEARS OF RXTE OBSERVATIONS

J. Mammei THE PREX AND CREX EXPERIMENTS

R. Mammei ULTRACOLD NEUTRONS AT TRIUMF

B. Niebergal NUMERICAL SIMULATIONS OF THE TRANSITION TO U,D,S QUARK MATTER

A. RojasABSOLUTE CROSS SECTION MEASUREMENTS OF THE 3He(

alpha,gamma)7Be REACTION USING THE DRAGON RECOIL SEPARATOR

A. Sanetullaev A NEW REACTION SPECTROSCOPY FACILITY IRIS AT TRIUMF

S1

Neutrino Physics Chair: D. Grant (University of Alberta)

50th Winter Nuclear & Particle Physics Conference 1

THE STATUS OF DEEP UNDERGROUND LABORATORIES AND THESCIENCE PROGRAMME AT SNOLAB.

N.J.T.Smith∗

SNOLAB

Several of the major questions studied in contemporary astro-particle and sub-atomic physics are performedthrough weak interaction studies or rare event searches. These require the ultra-quiet environment afforded by deepunderground facilities, where the cosmic radiation induced backgrounds in the detection systems are reduced to amanageable level. This talk will provide a review of the development plans for several deep underground facilitiesaround the world, highlighting the expansions to available laboratory experimental space that have recently occurred,or are planned in the near future.

The science programme at SNOLAB, the Canadian deep underground facility, will be described in greater detail, toprovide an overview of the science strands than can be explored with such a facility. These include direct searches forthe Galactic dark matter, the study of fundamental neutrino properties through the search for neutrino-less double-betadecay in candidate isotopes, and the study of non-terrestrial sources of neutrinos.

∗E-mail: [email protected]


STUDYING LOW ENERGY ATMOSPHERIC NEUTRINOS AT THESOUTH POLE WITH THE PINGU DETECTOR

K. Clark∗, for the IceCube CollaborationPennsylvania State University

IceCube and its low energy extension DeepCore have been deployed at the South Pole and taking data sinceearly 2010. With a neutrino energy threshold of about 10 GeV, DeepCore allows IceCube to access a rich variety ofphysics including searching indirectly for WIMP dark matter and the study of atmospheric neutrinos. Currently underconsideration is a new in-fill array, named PINGU, which would continue to lower the threshold for neutrino detection.This lowering of the threshold provides the potential to a great deal of new physics, including the determination ofthe neutrino mass hierarchy. This talk will discuss the PINGU detector and the new physics it makes available with afocus on the neutrino mass hierarchy.



MEASURING THE CHERENKOV LIGHT PRODUCED BY CHARGEDPIONS IN WATER

Sophie Berkman∗

University of British Columbia

Super-Kamiokande is a large water Cherenkov detector designed to measure properties of neutrinos, such as neu-trino oscillations. In Super-Kamiokande particles are identified by classifying the rings of Cherenkov light and, due tothe similarity of the rings, charged pions are one of the main backgrounds to identifying the muons produced by muon-neutrino interactions. Unlike muons, pions undergo hadronic interactions which may affect the amount and propertiesof the Cherenkov light they produce. These differences in the Cherenkov light production may make it possible todistinguish charged pions from muons. It is most important to understand the charged pions close to the Cherenkovthreshold because many of them are produced by neutrino interactions around this momentum where the detectionefficiency is especially sensitive to hadronic scattering. Furthermore, it is important to be able to tag the decay elec-trons produced by charged pions. This will make it possible to identify the muon-neutrino interaction CC1π+ whichproduces a muon and positively charged pion, and if the pion is not absorbed will result in two decay electrons. Thisinteraction currently has a large systematic error associated with it in analyses of Super-Kamiokande data. A smallintegrating cylinder filled with water was built to measure the total Cherenkov light from charged pions as well as thedecay electron yield in the momentum region close to the threshold. This measurement will automatically incorporatethe pion’s hadronic interactions and make it possible to reduce the systematic errors associated with charged pions atSuper-Kamiokande. Data was collected using the TRIUMF M11 beamline, and results will be presented.



OSCILLATION RESULTS FROM THE T2K EXPERIMENTS. Giffin∗,

University of Regina

For the T2K Collaboration

T2K is a long baseline neutrino oscillation experiment which sends an off-axis narrow band beam of neutrinosfrom Tokai to Kamiokande in Japan. I review its goals, and present the first T2K measurements that indicate a non-zero oscillation of muon neutrinos into electron neutrinos, and a disappearance of muon neutrino flux at Kamiokande.The best fit values from data taken so far are sin22θ23 = 0.98, ∆m2

32 = 2.65 x 10−3eV2, sin22θ13 = 0.094 (normalhierarchy) or sin22θ13 = 0.116 (inverted hierarchy).



EFFECT OF THE EMISSION SPECTRA OF WLS FIBERS ON LIGHTCOLLECTION IN SCINTILLATING BARS

A. Kolaceke∗, M. Barbi, S. Giffin, E. L. Mathie, R. TacikUniversity of Regina

C. LicciardiCarleton University

Wavelength shifting (WLS) fibers are used for light collection in the Fine Grained Detectors for the T2K experi-ment. The fibers are installed in scintillating bars and connected to Hamamatsu Multi-Pixel Photo-Counters (MPPC).The aim of this work is to study the effect of the emission spectra of the WLS fibers on the FGD light collectionsystem.

An UV LED was used as a source of light, and an Ocean Optics Inc. S2000 spectrometer was employed to measurethe light spectrum coming out of the fiber. At least six measurements were performed with the LED located at differentpositions on the fiber. The results were averaged to obtain the final values presented. Fibers with blackened andmirrored ends were analyzed, and the results were compared.

The MPPC photon detection efficiency, as provided by the manufacturer, was used to determine the contributionto the light attenuation due to differences in the light spectra between different positions of the LED on the fiber.

The results show that the light spectrum is modified depending on the LED position on the fiber. It was foundthat the MPPC’s detection efficiency decays exponentially with the distance between the incident signal and the de-tector (spectrometer). Considering this effect alone, and assuming multi-reflections in the mirrored fibers, the lightattenuation in the mirrored fibers is lower (3.7± 0.1)% in comparison to the blackened (4.7± 0.1)%.



PHYSICS MEASUREMENTS AT THE T2K NEAR DETECTOR

Christine Nielsen∗,University of British Columbia

For the T2K Collaboration

The near detector at 280m is part of the T2K long-baseline neutrino oscillation experiment with a neutrino beamfrom Tokai to Kamioka, and has been in operation for almost three years. The purpose of ND280 is to provide infor-mation about the neutrino beam before oscillation, such as measuring background rates and the energy spectrum of thebeam. ND280 consists of multiple parts: a tracker with two active scintillator-bar target systems (FGDs) sandwichedbetween three large time projection chambers (TPCs), a pi-zero detector, surrounding electromagnetic calorimetersand a large dipole magnet for charged particle tracking. This talk will be about the physics measurements of the neardectector and future extensions to this.



S2 Nuclear Medicine/Antihydrogen

Chair: G. Ball (TRIUMF)


CLINICAL DOSIMETRY: EVOLUTION, STATE OF THE ART AND FUTURE DIRECTIONS

J. Eduardo Villarreal-Barajas . Department of Radiation Oncology, University of Calgary

The clinical dosimetry origins can be traced to the discovery of x-rays in 1895 by Wilhelm Rœntgen

and the discovery of radioactivity by Henry Becquerel the following year. Since these two discoveries and their almost immediate clinical applications, the need to assess the amount of radiation absorbed by the irradiated human tissues has been critical for the safe and effective use of ionizing radiations. This presentation will address the evolution of the field of clinical dosimetry and its close relation with the development of radiation protection standards.

The development of radiation detectors used for radiation therapy applications will be discussed on the light of the developments of Orthovoltage x-ray machines (up to 300 kV), Cobalt-60 gamma rays and x-ray linear accelerators (up to 25 MeV). Particular emphasis will be given to the evolution and state of the art of solid state detectors used in clinical dosimetry.

The presentation will conclude with an overview of the ongoing efforts to produce novel radiation detector materials for faster, more accurate, 3D and real time clinical dosimetry. E-mail: [email protected]


MODELING PROTON THERAPY: A STUDY OF SECONDARYNEUTRON EMISSIONS

E. Himbeault∗, M. Trinczek, N. Zacchia, E. Blackmore, C. HoehrTRIUMF, Vancouver, BC, Canada

TRIUMF has been treating ocular melanomas using a dedicated proton beam line since 1995 [1] with the facilityundergoing only minor changes during this time. During treatment, secondary neutron emissions from the beam com-ponents is believed to contribute an appreciable medical dose to the patient. In order to assess the dose contribution ofsecondary neutrons, a representative Monte-Carlo model of the existing facility was developed.

All elements in the beam line were simulated with FLUKA [2] and the results optimized against experimental data.The raw Bragg peak, spread-out Bragg peak, transmission curve, beam profile, and the amount of deposited dose fromsecondary neutron emissions were all calculated. Experimental measurements to verify the simulation were performedwith a silicon PIN diode (BPW34) in a water box and a neutron detector (BF3).

Good agreement between experimental data and simulation was achieved. A validation of the simulation willbe presented by comparing measured primary beam characteristics with simulation, as well as neutron dose ratesestimated by direct measurement and simulation.

The FLUKA model can now be used to reliably assess dose rates from secondary neutrons, and can further beused to evaluate the impact of changes made to the beam line on the beam quality and the level of patient dose fromsecondary particles.

References

[1] E. Tran et al., Outcomes of Proton Therapy for peripapillary Choroidal Melanoma at the BC Cancer Agency Int.J. Radiat. Oncol. Biol. Phys. (2012) vol. 83, pp. 1425-1431.

[2] www.fluka.org.G. Battistoni, S. Muraro, P.R. Sala, F. Cerutti, A. Ferrari, S. Roesler, A. Fasso, J. Ranft, The FLUKA code:Description and benchmarking Proceedings of the Hadronic Shower Simulation Workshop 2006, Fermilab 6–8September 2006, M. Albrow, R. Raja eds., AIP Conference Proceeding 896, 31-49, (2007)A. Ferrari, P.R. Sala, A. Fasso, and J. Ranft, FLUKA: a multi-particle transport code, CERN-2005-10 (2005),INFN/TC-05/11, SLAC-R-773.



RESONANT QUANTUM TRANSITIONS IN ANTIHYDROGEN ∗

Tim Friesen †,University of Calgary

On behalf of the ALPHA collaborationhttp://alpha.web.cern.ch

The first resonant quantum interaction with antihydrogen has recently been demonstrated by the ALPHA col-laboration at CERN [1]. Antihydrogen atoms in a ‘low-field seeking’ ground state are magnetically confined by anIoffe-type atom trap [2]. Microwave radiation induces a magnetic resonance transition, flipping the positron spin andleaving the antihydrogen atom in an unconfined state that will leave the trap. Resonant interaction is demonstrated bycomparing the survival rate of trapped antihydrogen atoms irradiated by on-resonant microwaves to those irradiatedby off-resonant microwaves. Significantly fewer antihydrogen atoms survive when exposed to on-resonant radiation(0.02 per attempt) compared to off-resonant radiation (0.21 per attempt). Additional evidence is provided by the spatialand temporal distributions of the annihilations of spin flipped antihydrogen atoms. This is a significant step towardsprecision spectroscopy of antihydrogen and sensitive tests of CPT symmetry through comparison with the hydrogenspectrum.

[1] C. Amole et al. (ALPHA Collaboration), Nature, 483, 439 (2012).[2] G. B. Andresen et al. (ALPHA Collaboration), Nature 468, 673 (2011).

∗This work was supported by CNPq, FINEP/RENAFAE (Brazil), ISF (Israel), FNU (Denmark), VR (Sweden), NSERC, NRC/TRIUMF, AITF,FQRNT (Canada), DOE, NSF (USA), EPSRC, the Royal Society and the Leverhulme Trust (UK).

†E-mail: [email protected]


S3 Nuclear Spectroscopy

Chair: D. Leahy (University of Calgary)


LASER SPECTROSCOPYWITH EXOTIC SPECIES

M.R. Pearson�

TRIUMF

There are few properties of atomic nuclei more fundamental than their shape, size and spin. Laser spectroscopy

offers a highly sensitive, non destructive method of probing these properties by utilising the hyper�ne interaction.

This interaction between the nucleus and its surrounding electrons allows for a variety of highly precise, ef�cient

atomic techniques to be employed whilst causing minimal disturbance to the nucleus being studied. When carried out

at a radioactive beam facility where long chains of isotopes are available this results in a detailed knowledge of the

evolution of the nuclear shape from stability out to the extremes of the nuclear chart. This talk will outline the basic

techniques used a various on-line facilities as well as recent results and future plans.

�E-mail: [email protected]


IN-TRAP DECAY SPECTROSCOPY AT THE TRIUMF FACILITY∗

A. Lennarz†, D. FrekersWestfalische Wilhelms-Universtitat Munster, Germany and TRIUMF, Canada

A. Grossheim, A. Chaudhuri, U. Chowdhury, A. Gallant, A.A. Kwiatkowski, T. MacDonald, B.E.Schultz, M.C. Simon, V.V. Simon, J. Dilling

TRIUMF, Canada

C. Andreoiu, S. SeerajiSimon Fraser University, Canada

The TRIUMF TITAN ion-trap facility consists of a unique combination of ion traps, which offers the opportunityto perform in-trap X-ray and gamma-ray spectroscopy on radioactive isotopes. The TITAN-EC project deals with themeasurement of the electron-capture branching ratios (ECBRs) of short-lived intermediate nuclei in double-beta (dbb)decays. The ECBRs are important for evaluating the nuclear matrix elements (NME) involved in the dbb-decay forboth processes, the two-neutrino and the neutrinoless decay. The beta and the EC decay branches provide informationabout the ground-state wave function, and many theoretical models aimed at calculating dbb-decay NMEs fail inreproducing simultaneously both decay properties. The EC branches are in most cases suppressed by several ordersof magnitude relative to their beta counterparts and are either poorly known or not known at all. We describe a noveltechnique to measure the ECBRs, where the TITAN ion traps and the ISAC radioactive beam facility at TRIUMFare the central components. The presence of the ion trap’s magnetic field offers the advantage that electrons fromthe beta decays are directed on axis out of the trap and away from the X-ray detectors. A total of seven SiLi X-raydetectors are surrounding the trap perpendicular to the beam axis. A successful experiment with 124Cs was performedin November 2012 and prove the feasibility of this setup to measure low ECBRs. The TITAN-EC experiment is part ofa larger project dealing with the experimental determination of dbb-decay NMEs using also hadronic charge-exchangereactions, which provide further insight into the nuclear properties relevant for dbb-decays.

∗Work supported by the Natural Sciences and Engineering Research Council of Canada and the National Research Council of Canada and theDeutsche Forschungsgemeinschaft (DFG) under grant-number no. FR 601/3-1.



OPTIMISING DIGITAL SIGNAL PROCESSING ALGORITHMS FORHIGH RESOLUTION GAMMA-RAY SPECTROSCOPY WITH THE

GRIFFIN SPECTROMETER

A.K. Cheeseman∗, A.B. Garnsworthy, C.J. Pearson, D. Bishop, C. Ohlmann

TRIUMF, Vancouver BC, Canada

J-P. Martin

Universite de Montreal, Montreal QC, Canada

C.E. Svensson

University of Guelph, Guelph ON, Canada

Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei (GRIFFIN) is a new high efficiency gamma-ray spectrometer being developed to replace the 8pi spectrometer at TRIUMF’s Isotope Separator and ACcelerator(ISAC) facility for decay spectroscopy. GRIFFIN will consist of an array of up to 16 unsegmented Hyper-Pure Ger-manium (HPGe) clover detectors. It will use a state-of-the-art, custom designed digital Data Acquisition (DAQ) sys-tem. The completion of the GRIFFIN project will support research in nuclear structure, fundamental symmetries, andnuclear astrophysics.

This presentation covers the optimisation of the various firmware algorithms to be implemented on the GRIFFINelectronics modules to extract the energy and time values from the preamplifier signals, with the goal being to achieveenergy resolutions equivalent, or superior, to those achieved by traditional analogue systems. The system will alsohave an improved ability to detect low energy signals and handle high counting rates where each HPGe crystal isoperating in excess of 50 kHz.

The results of several tests performed using offline analysis of real waveforms collected using TIGRESS TIG10modules show that by optimising the algorithm parameters, a digital system is capable of achieving energy resolutionscomparable to those achieved by analogue shaping methods. Through the use of additional filtering techniques thesignal-to-noise ratio of the waveforms was improved significantly such that pulses equivalent to gamma-ray energiesas low as 5 keV can be detected with good efficiency. The next steps will be to implement these algorithms in firmwareand perform online testing to obtain the same quality of results in real-time signal processing.



ACCEPTANCE TESTS OF GRIFFIN HPGe CLOVERS AT SFUU. Rizwan∗, C. Andreoiu, A. Chester, D.S. Cross, J.L. Pore, S. Seeraji, K. Starosta, P. Voss,

J. WilliamsSimon Fraser University

A.B. Garnsworthy, G.C. Ball, D. Bishop, D. Brennan, A. Cheeseman, B. Davids, G. Hackman,R. Kruecken, C. Lim, C.A. Ohlmann, C.J. Pearson

TRIUMF

P.E. Garrett, E.T. Rand, C.E. SvenssonUniversity of Guelph

J-P. MartinUniversite de Montreal

Gamma Ray Infrastructure For Fundamental Investigation of Nuclei (GRIFFIN) is a state of the art facility fordecay spectroscopy being built at TRIUMF in Vancouver, British Columbia. It is designed to replace the 8π array,composed of 20 coaxial Hyper Pure Germanium (HPGe) crystals, currently used in conjunction with a suite of aux-iliary detectors at the TRIUMF Isotope Separator and Accelerator (ISAC) facility to study the structure of nuclei farfrom stability populated in β decay of beams delivered by ISAC.

Although the 8pi, originally constructed 25 years ago as a high-spin spectrometer, has been repurposed for beta-decay spectroscopy at TRIUMF-ISAC, GRIFFIN has been specifically optimized for high-efficiency decay spec-troscopy. It will be composed of 16 detectors, each with four crystals in a clover configuration. Each crystal has anefficiency of ≥38% relative to that of 3′′ × 3′′ NaI detector at a source-detector distance of 25 cm. When assembled,GRIFFIN will be 17 times more efficient than the 8π array at 1 MeV and more than 40 times more efficient at 10 MeV.

A necessary component of GRIFFIN is the high-rate DAQ system, capable of accepting event rates of up to 50kHz per GRIFFIN crystal, which is well suited to the demands of both the nuclear-structure/astrophysics program aswell as the high-precision superallowed Fermi beta-decay program. GRIFFIN’s design allows for coupling with theexisting 8π auxiliary detectors as well as the new detectors coming on-line at ISAC such as the DEutrated SCintillatorArray for Neutron Tagging (DESCANT). The expected sensitivity of GRIFFIN will take full advantage of excitingopportunities opened by the development of the actinide target at ISAC as well as the construction of the new AdvancedRare IsotopE Laboratory (ARIEL) facility.

The individual GRIFFIN detectors are arriving for tests at Simon Fraser University (SFU) and will continue to doso until the middle of 2014. To accommodate these detectors, an automatic liquid nitrogen cooling system and a testingstation using an analog and a digital DAQ has been setup. While the digital DAQ is used for resolution and efficiencytests, the analog DAQ is used to examine the timing resolution of each core with respect to a BaF2 scintillator. Thetiming response of GRIFFIN detectors is crucial for envisioned gamma-ray coincidence studies of weak decays in thepresence of high intensity contaminants.

Each detector arriving at SFU is bench marked against a specification list defined by the GRIFFIN collaborationvia measurements of energy and timing resolution, efficiency, and preamplifier, electrical, and cryogenic properties.Each GRIFFIN detector must satisfy all of these various requirements to be accepted for use at TRIUMF-ISAC. As ofthe end of 2012, four detectors have been fully tested and accepted. The details of the tests done on the detectors atSFU will be presented.



INVESTIGATION OF THE E2 AND E3 MATRIX ELEMENTS IN200Hg USING INELASTIC SCATTERING∗

E. T. Rand†, V. Bildstein, P. E. Garrett, B. Hadinia, D. S. Jamieson, B. Jigmeddorj, K. G. Leach,C. E. Svensson

Department of Physics, University of Guelph, Guelph, Ontario, Canada N1G 2W1

G. C. BallTRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3

T. FaestermannPhysik Department, Technische Universitat Munchen, Garching, Germany D-85748

R. Hertenberger, H.-F. WirthFakultat fur Physik, Ludwig-Maximilians-Universitat Munchen, Garching, Germany D-85748

A nuclear structure campaign has been initiated investigating the isotopes of Mercury around mass 199. Currently199Hg provides the most stringent limit on an atomic electric dipole moment (EDM). The observation of a permanentEDM would represent a clear signal of CP violation from new physics beyond the Standard Model. The EDM of anatom is induced by the Schiff moment, the lowest order time-reversal odd moment of a nucleus that is measurable ina neutral atom. Theoretical calculations for 199Hg are very difficult and give varied predictions for the excited-statespectrum. Understanding the E2 and E3 strengths in 199Hg will make it possible to develop a nuclear structure modelfor the Schiff strength based on these matrix elements and thereby constrain present models of the contribution ofoctupole collectivity to the Schiff moment of the nucleus.

The most direct way of measuring the matrix elements connecting the ground state to excited states is throughinelastic hadron scattering. The high level density of a heavy odd-A nucleus like 199Hg is extremely challenging.Fortunately, complimentary information can be determined for states in the neighbouring even-even isotopes of 198Hgand 200Hg. Additionally, single-nucleon transfer reactions on targets of even-even isotopes of Mercury can yieldimportant information on the single-particle nature of 199Hg.

The work presented here comprises two experiments using a 22 MeV deuterium beam impinged on an isotopicallyenriched target of 200Hg32S. The first experiment is an inelastic deuteron scattering experiment, 200Hg(d, d′)200Hg,which consists of up to 20 angles ranging from 10◦ to 115◦. The second experiment is a single-nucleon transfer reactioninto 199Hg, 200Hg(d, t)199Hg, and includes 10 angles from 5◦ to 50◦ up to an excitation energy of ∼ 3 MeV. Theseexperiments were performed using the Q3D spectrograph at the Maier-Leibnitz Laboratory (MLL), a joint facilityof Ludwig-Maximilians-Universitat Munchen (LMU) and the Technische Universitat Munchen (TUM). The Q3Dspectrograph offers unmatched energy resolution (typically < 10 keV) and sensitivity for these types of experiments.Preliminary results from these experiments will be presented.

∗Work supported by the Natural Sciences and Engineering Research Council of Canada and the National Research Council of Canada.†E-mail: [email protected]


STRUCTURE STUDY OF 110CD VIA A HIGH-STATISTICSβ+/EC-DECAY 110IN MEASUREMENT

A. Diaz Varela, P.E. Garrett, J.C. Bangay, G.A. Demand, P. Finlay∗ , K.L. Green, B. Jigmeddorj,K.G. Leach† , A.A. Phillips, A.J. Radich, E.T. Rand, M.A. Schumaker‡ , C. Sumithrarachchi§ ,

C.E. Svensson, S. Triambak¶ , J. Wong

Department of Physics, University of Guelph, Guelph, ON, N1G2W1, Canada

W.D. Kulp, J.L. Wood

Department of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA

S.W. Yates

Department of Physics & Astronomy, University of Kentucky, Lexington, KY, 40506-0055, USA

G.C. Ball, A.B. Garnsworthy, G. Hackman, J.N. Orce‖

TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T2A3 Canada

D.S. Cross

Department of Chemistry, Simon Fraser University, Burnaby, BC, V5A1S6, Canada

The collective Bohr model and the IBM have both used the stable even-even Cd isotopes as classic examples ofvibrational nuclei for decades. Experiments with the (α,2n) reaction,β decay measurements and an (n, n′γ) studyhave identified multi-phonon states in the110Cd decay scheme indicating vibrational motion. These studies have alsosuggested intruder configurations based on more deformed 2p-4h proton excitations. There is however evidence ofthe breakdown of vibration motion in the low-spin states leading to systematic deviations at the three-phonon levelthat occur across the Cd isotopic chain. Through work done on112Cd an alternative interpretation has been proposedwhere the three-phonon0+ state is assigned as an intruder excitation.

A study of the110In β+/EC decay was performed at the TRIUMF Isotope Separator and Accelerator (ISAC)facility to probe the inherent nature of the110Cd nucleus. The data were collected in scaled-down gamma singles,gamma-gamma coincidence, and gamma-electron coincidence mode. The data were sorted and a random-backgroundsubtracted gamma-gamma matrix was created containing a total of 850 million events. We expanded the level schemeof 110Cd significantly by identifying approximately 70 levels under 3.8 MeV, including 12 new ones, and doubled thenumber of previously observed transitions from these levels to 250. Branching fractions as low as5.1(3)× 10−4 havebeen extracted.

The branching ratios were combined with a reanalysis of an (n, n′γ) reaction with monoenergetic neutrons forthe calculation of B(E2) values. The previous interpretation of the decay scheme of the excited0+ states requiredthat there must be strong-mixing between assigned phonon states and the deformed intruder states. An absence ofpredicted linking transitions between these configurations refutes this, and has lead to the proposal of aγ-soft rotor,or O(6) nucleus, rather than a vibrational, or U(5) pattern.

∗Present address: Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven, B-3001, Leuven, Belgium†Present address: TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T2A3 Canada‡Present address: Department of Physics, Laurentian University, Sudbury, ON, P3E 2C6, Canada§Present address: National Superconducting Cyclotron Center, Michigan State UniversityEast Lansing, MI 48824, USA¶Present address: Dept. of Physics and Astrophysics, University of Delhi, Delhi 110 007, India‖Present address: Dept. of Physics, University of the Western Cape, P/B X17, Bellville ZA-7535, South Africa


S4 Measurements of Nuclear

Properties Chair: D. Hobill (University of Calgary)


HIGH PRECISION MASS MEASUREMENTS OF RARE ISOTOPES ATTITAN∗

Stephan Ettenauer†

TRIUMF, Vancouver BC, Canada

Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada

Department of Physics, Harvard University, Cambridge, Massachusetts , USA

U. Chowdhury, A. T. Gallant, A. Lennarz, T. MacDonald, V. V. Simon, T. Brunner, A. Chaudhuri,Alexander Grossheim, A.A. Kwiatkowski, E. Mane, M. C. Simon, B. E. Schultz, C. Andreoiu, M.

Good, D. Frekers, D. Lunney, M. R. Pearson, and J. DillingTRIUMF, Vancouver BC, Canada

M. Brodeur, A. Lapierre, R. Ringle,National Superconducting Cyclotron Laboratory, Michigan State University, Michigan, USA.

Atomic masses of rare isotopes continue to be fundamental ingredients for studies of nuclear structure, nuclear as-trophysics, and fundamental symmetries. In the endeavor to explore the nuclear mass surface towards the limits ofnuclear existence, TRIUMFs Ion Trap for Atomic and Nuclear Science (TITAN) has pioneered Penning trap massspectrometry along two aspects: Firstly, it is uniquely capable to handle very short lived nuclides with half-lives evenbelow 10 ms [1]. Secondly, it is pushing on the precision frontier by utilizing an electron beam ion trap to breed short-lived nuclides delivered from ISAC / TRIUMF to a higher charge state. The precision of the mass measurement in aPenning trap is thereby boosted by a factor identical to the charge state q of the ion. In combination with advancedexcitation schemes such as the recently introduced Ramsey technique [3], this novel approach for rare isotopes opensthe path towards gains of 1-2 orders of magnitude in experimental precision.

Recently, these unique experimental capabilities at a radioactive ion beam facility allowed TITAN to make con-tributions in a variety of physics questions. These range from nuclear structure topics as neutron-rich Ca-isotopes asa superb testing ground for three-nucleon forces [4] or shell gaps in the island of inversion [5], over superallowednuclear beta decays to determine Vud of the Cabibbo-Kobayashi-Maskawa matrix [2], to solar neutrino physics [6].For the latter, the energy threshold (or Q-value) of 71Ga(ν, e−)71Ge was determined accurately using ions with up toq = 22+. Previously this Q-value represented a nuclear physics uncertainty relevant for the discrepancy observed inthe SAGE and GALLEX neutrino calibration measurements [7].

This talk will provide an overview over the TITAN facility and a summary of recent results.

[1] M. Smith et al., Phys. Rev. Lett. 101, 202501 (2008)[2] S. Ettenauer et al., Phys. Rev. Lett. 107, 272501 (2011)[3] S. George et al., Phys. Rev. Lett. 98, 162501 (2007)[4] A. T. Gallant et al., Phys. Rev. Lett. 109, 032506 (2012)[5[ A. Chaudhuri et al., in preparation[6] D. Frekers, M.C. Simon et al., in preparation[7] C. Giunti and M. Laveder, Phys. Rev. C 83, 065504 (2011)

∗Work supported by the Natural Sciences and Engineering Research Council of Canada and the National Research Council of Canada†E-mail: [email protected]


HIGH-PRECISION HALF-LIFE MEASUREMENTS FOR THESUPERALLOWED β+ EMITTER 14O∗

A. T. Laffoley† C. E. Svensson, A. Diaz Varela, R. Dunlop, P. Finlay, P. Garrett, B. Hadinia,D. S. Jamieson, K. G. Leach

Department of Physics, University of Guelph, Guelph, Ontario

G. F. Grinyer, H. BouzomitaGANIL, CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen, France

G. C. Ball, A. B. Garnsworthy, G. Hackman, S. Ketelhut, E. Tardiff, C. UnsworthTRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia

C. Andreoiu, D. S. CrossDepartment of Chemistry, Simon Fraser University, Burnaby, British Columbia

R. A. E. AustinDepartment of Astronomy & Physics, Saint Mary’s University, Halifax, Nova Scotia

B. Blank, J. GiovinazzoCENBG, Universite Bordeaux I – CNRS/IN2P3, 33175 Gradignan, France

J. R. LeslieDepartment of Physics, Queens University, Kingston, Ontario

High-precision measurements of superallowed Fermi β decays between 0+ isobaric analog states have provided in-valuable probes of the Standard Model description of the electroweak interaction. These measurements have been usedto test the conserved vector current (CVC) hypothesis, set limits on the existence of scalar and right-handed currentsin the electroweak interaction, and search for other possible extensions of the Standard Model. Half-life measurementsfor the lightest of these emitters, 10C and 14O, are of particular interest as it is the low-Z superallowed decays that aremost sensitive to a possible scalar current contribution.

There are two primary methods for measuring the superallowed β decay half-life of 14O; one can directly countthe β particles or measure the γ activity since, with a branching ratio of 99.4%, 14O decays to an excited state ofthe daughter 14N which then emits a 2.3 MeV γ-ray. Comparing the experiments that detected the 2.3 MeV γ-raysand those that perform β counting measurements yields results that disagree with each other at the level of 0.11%or 1.5σ. The same systematic discrepancy, at a level of 0.09% or 1.4σ, exists for the current 10C half-life measure-ments. This provides motivation for a set of high-precision half-life measurements for 10C and 14O via both γ-rayphotopeak and direct β counting techniques at TRIUMF’s Isotope Separator and Accelerator (ISAC) facility to ad-dress the systematics between the methods used. The detector set-up used consists of the 8π γ-ray Spectrometer—aspherically symmetric array consisting of 20 Compton suppressed High-Purity Germanium (HPGe) detectors—and theZero-Degree Scintillator—a fast plastic scintillator placed behind the tape transport system within the 8π. This talk willhighlight the importance of these measurements and preliminary half-life results for 14O will be presented.



EXPLORING A CALIBRATION DISCREPANCY AT SAGE & GALLEX :THE DIRECT Q-VALUE MEASUREMENT OF 51Cr(e, !e)51V AT TITAN

T.D. Macdonald, A.T. Gallant, J. DillingDepartment of Physis & Astronomy, The University of British Columbia, Vancouver, Canada

TRIUMF, 4004 Wesbrook Mall, Vancouver, Canada

A. Chaudhuri, A. Grossheim, A.A. Kwiatkowski, B.E. Schultz, M.C. SimonTRIUMF, 4004 Wesbrook Mall, Vancouver, Canada

C. Andreoiu, J.C. BaleDepartment of Chemistry, Simon Fraser University, Burnaby, Canada

U. ChowdhuryDepartment of Physics, University of Manitoba, Winnipeg, Canada


D. Frekers, A. LennarzInstitut fur Kernphysik, Westfalishe Wilhelms-Universitat, Munster, Germany

V.V. SimonMax Planck Institute for Nuclear Physics, Heidelberg, Germany


TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) uses Penning trap mass spectrometry to probenuclear structure, nuclear astrophysics, and the fundamental symmetries of nature. Measurements were recently per-formed to address uncertainties in the nuclear structure of isotopes that were used in the solar neutrino experimentsSAGE and GALLEX. These experiments used gallium neutrino detectors to detect the first low-energy solar neutri-nos and confirm low-energy neutrino oscillations [1]. However, there is an unresolved discrepancy in the calibrationof these detectors; the calibration measurements using 51Cr(e,!e)51V do not agree with theoretical expectations [2].Penning trap mass spectrometry is the most accurate and precise method available for performing direct mass mea-surements on nuclides [3], and most recently a Q-value measurement of the calibration reaction 51Cr(e,!e)51V wasperformed. The results will rule out whether or not the discrepancy at SAGE and GALLEX was caused by an impreciseQ-value determination. An overview of the TITAN facility and the preliminary results will be provided.

[1 ] J. Bahcall, et al, Phys Rev C, 56 3391 (1997)

[2 ] J.N. Abdurashitov, et al, Phys Rev C, 80 015807 (2009)

[3 ] K. Blaum, Phys Rep, 425 1 (2006)


NPDGAMMA - PARITY VIOLATION IN CAPTURE OF COLDNEUTRONS ON PROTONS

Mark McCrea∗University of Manitoba

for the NPDGamma Collaborations

The NPDGamma experiment aims to measure the parity violating asymmetry in the direction of gamma ray emis-sion from polarized cold neutrons capturing on an unpolarized proton target. The goal is to measure this asymmetrywith an accuracy of 10−8 to allow comparison to theoretical predictions of the strength of the hadronic weak interac-tion between nucleons. A liquid para-hydrogen proton target is used to capture the polarized neutron beam. The gammaray emission direction is measured using an array of 48 CsI(Th) detectors with a 3π acceptance angle. The neutronspin direction is reversed in a pseudo random sequence to control for systematics during data taking. NPDGamma hascompleted commissioning and is currently taking hydrogen data in the Fundamental Neutron Physics Beamline at theSpallation Neutron Source.

∗E-mail:[email protected]


MEASUREMENT OF PROTON SPIN POLARIZABILITIES @ MAMI

Dilli Raj Paudyal∗,University of Regina

The nucleon polarizabilities are fundamental hadronic structure properties that describe its response to an appliedelectric or magnetic field. While the spin independent electric and magnetic polarizabilities of the nucleon have beenmeasured, little effort has been made to extract the spin dependent polarizabilities. We plan to measure the spin polar-izabilities of the proton using real Compton scattering off the proton at the MAMI tagged photon facility. The methodinvolves precise measurement of the beam and beam-target asymmetries. The beam asymmetry

∑3 is measured with

a linearly polarized photon beam and an unpolarized liquid-hydrogen target, whereas the beam-target asymmetries∑2x,

∑2z are measured via a circulary polarized photon beam and a transversely and a linearly polarized butanol tar-

get in the resonance region (E = 250− 310 MeV). Our major plan focuses on the measurement of these asymmetriesat different energies and angles. Together with constraints from the spin independent polarizabilities αE1 and βM1,the forward spin polarizability (γ0), and QCD based models, should allow us to extract all four spin polarizabilities(γE1E1 , γM1M1 , γM1E2 , γE1M2) independently with small statistical, systematic and model-dependent uncertainitiesfrom the experimental data.



MEASUREMENT OF THE SPIN POLARIZABILITIES OF THEPROTON

C. Collicott∗

Dalhousie UniversitySaint Mary’s University

Recent experiments have been conducted at the MAMI tagged photon facility with the goal of extracting the spinpolarizabilities of the proton. These spin polarizabilities are fundamental structure constants that describe the responseof the proton’s spin to applied electric and magnetic fields. Although theoretical approaches have been applied to de-termine these structure constants (dispersion relations, ChPT, lattice QCD), the individual spin polarizabilities have yetto be measured experimentally. Through the measurement of three beam and beam-target asymmetries, derived fromsingle and double polarization experiments involving real Compton scattering off the proton, the spin polarizabilitiesof the proton will be measured experimentally for the first time. Experimental data have been acquired for two ofthe three required asymmetries at the MAMI tagged photon facility in Mainz, Germany. Recent results and ongoinganalysis from these measurements will be presented.



S5 The Higgs and Standard Model

Physics Chair: M. Wieser (University of Calgary)


DISCOVERY OF A HIGGS-LIKE BOSON AT THE LHC∗

A. Canepa†, for the ATLAS Collaboration

TRIUMF

The year 2012 represents a “defining moment in the history of science”. Both the ATLAS and CMS experimentsat the Large Hadron Collider announced the discovery of a Higgs-like particle. This talk will describe the analysistechniques adopted for the discovery and its significance. It will also discuss further measurements developed todetermine the exact nature of this new particle. The most recent results from the ATLAS experiment will be presented.

∗Work supported by the Natural Sciences and Engineering Research Council of Canada and the National ResearchCouncil of Canada.†E-mail: [email protected]


DIRECT STOP PRODUCTION IN BOOSTED HADRONIC FINALSTATES∗

M. LeBlanc†

University of Victoria

Supersymmetry (SUSY), is a novel symmetry introduced to the Standard Model of Particle Physics in many sce-narios of physics beyond the Standard Model which relates particles of half-integer spin (fermions) to those of integerspin (bosons). This additional symmetry takes the form of partner-particles for each particle in the standard modelnamed superpartners, with the same internal quantum numbers but spin differing by half a unit. Supersymmetry hasnot yet been observed experimentally, which means that Supersymmetry must be spontaneously broken: the super-partners must possess heavier masses than their Standard Model counterparts. According to arguments in favour ofnaturalness, the stop mass should be near the electroweak scale (O(1 TeV)) in order to help to explain the Higgs massfine-tuning problem.

Decay channels of the stop depend on the spectrum of supersymmetric masses present in any particular model. Inthis analysis, the scope is restricted to cases where the only possible decays are through weak channels, particularlythe neutral current decay to a top quark and the lightest neutralino, which is also the lightest supersymmetric particle(LSP). In this scenario, the neutralinos are prohibited by R-parity from decaying further and pass undetected throughthe ATLAS detector, providing missing transverse energy to the final state. When the stops are massive they will beproduced at rest, and the daughter top quarks will become boosted in the lab frame. In these cases, the jets originatingfrom the top decays become collimated, and the use of jets with large radii (Anti-KT algorithm distance parameterR = 1.0) to contain all of the top decay products becomes possible. The possible final states are determined bythe possible standard-model decays of the top quarks. The fully hadronic decay channel, which contains six jets andmissing energy, is the focus of this study:

pp→ tt∗ → (tχ01)(tχ0

1) → (bqqχ01)(bqqχ0

1). (1)

The results of a preliminary survey of the use of jets with large radii to examine this process in the regime ofboosted final states will be presented. The dataset used corresponds to an integrated luminosity of 4.306 fb−1 of ppcollisions collected at

√s = 7 TeV recorded during 2011 by the ATLAS detector, the largest of six experiments

currently installed in the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN).

∗Work supported by the Natural Sciences and Engineering Research Council of Canada.†E-mail: [email protected]


The GlueX Experiment: Taking Measurements from the Barrel Calorimeter*

Shaun Krueger† Department of Physics, University of Regina, Regina, SK S4S 0A2

One of the primary detector systems involved in the GlueX project at Jefferson Lab is the Barrel

Calorimeter (BCAL). The BCAL consists of 48 wedge shaped blocks made from alternating layers of corrugated lead sheets and 1 mm diameter, dual-clad, scintillating fibres. In order to take measurements from this BCAL, 40 light guides are attached to each end of each module and Silicon Photomultipliers (SiPMs) are attached to those. As the SiPM gain depends on their supplied voltage it is necessary to deliver as close to ideal operating voltage as possible to ensure uniform gain across the SiPMs; given that 3840 SiPMs must be used, this can be an onerous task. The electronic circuit board configuration and overall assembly and preliminary tests will be presented.

* Work supported by the Natural Sciences and Engineering Research Council of Canada and Jefferson Lab under a DOE contract. † Email: [email protected]


CHERENKOV MIRROR REFLECTIVITY MEASUREMENTS FORHALL C AT JEFFERSON LAB

Wenliang Li∗,

University of Regina

Jefferson Lab (JLab) has undertaken the 12 GeV Upgrade to double the accelerating energy of its electron beam.This attracts many interesting proposals to probe the quark-gluon nature of nuclear matter at higher energy, therefore anew set of experimental equipment is required. Hall C of JLab has planned to construct a new Super High MomentumSpectrometer (SHMS) to replace the existing Short Orbit Spectrometer (SOS). The University of Regina is assignedto construct the Heavy Gas Cherenkov (HGC) Detector as part of the SHMS focal plane detectors. The HGC consistsof four aluminized mirrors which are required to reflect 70-90% of UV photons between 200-400 nm wavelength. Inthis talk, we present latest SHMS HGC mirror reflectivity results obtained with the reflectivity measurement setup atJLab. This setup uses the lock-in amplification technique, which uses a photo-diode instead of a PMT, and is capableof measuring large size optics up to 60 cm X 55 cm.



THE QWEAK EXPERIMENT: PERFORMING THE FIRST DIRECTMEASUREMENT OF THE WEAK CHARGE OF THE PROTON

S. MacEwan ∗

University of Manitoba

The Qweak experiment has performed the first measurement of the weak charge of the proton QpW by measuring

the parity-violating asymmetry in the elastic scattering of longitudinally polarized electrons from a liquid Hydrogentarget. The experiment ran over a period of 2 years at Jefferson Lab’s Hall-C , using an >85% polarized electronbeam at currents reaching 180µA, with beam helicity reversal rate of 1 kHz. The beam electrons were scattered off ofprotons in a 2000 W liquid hydrogen target and focused onto a set of eight large, quartz Cherenkov detectors, by an 8sector toriodal spectrometer. The asymmetry was formed from the measured difference in the scattered electron yieldas a function of beam helicity.

The experiment was performed at low momentum transfer Q2 ∼ 0.026 (GeV/c)2, where contributions to QpW

from hadronic effects are minimized and well measured by previous experiments. At this momentum transfer, a precisemeasurement of the proton weak charge is therefore a direct measurement of the running of the weak mixing angle,which is precisely predicted by the Standard Model. Qweak is expected to provide a 0.3% measurement of sin2 θW ,resulting from a 4.2% measurement of the weak charge of the proton. At this precision, Qweak constitutes a test forphysics beyond the Standard Model with a sensitivity of up to 2 TeV for an observed deviation from the theoreticalprediction. In the absence of an observed deviation, the measurement provides the best constraints on the up and downquark weak charges to date.

The analysis of the full data set is ongoing. In this talk, I will provide an overview of the physics justification,experimental methodology and results from a small subset of the the data corresponding to a 25% weak charge mea-surement, which already constitutes a significant constraint on the quark weak charges.



THE TOPOLOGICAL CASIMIR EFFECT∗

M. van Caspel†, C. Cao, A.R. ZhitnitskyDepartment of Physics & Astronomy, University of British Columbia

The conventional Casimir effect manifests itself as a quantum-mechanical force between two plates, that arisesfrom the quantization of the electromagnetic field in the enclosed vacuum. In this talk the possibility is discussed of anextra, topological term in the Casimir energy at finite temperatures. This topological Casimir effect emerges due to thenontrivial topological features of the gauge theory: the extra energy is the result of tunnelling transitions between statesthat are physically the same but topologically distinct. It becomes apparent when examining, for instance, periodicboundary conditions. We explicitly calculate the new term for the simplest example of such a system, consisting oftwo large plates in the x-y plane, closely separated. Toroidal boundary conditions cause an integer-valued topologicalflux in the z-direction, giving rise to additional vacuum energy. By dimensional reduction, this system is closely relatedto two dimensional Maxwell theory on a torus, which is well understood. We find that the topological term is extremelysmall compared to the conventional Casimir energy, but that the effect could be very sensitive to an external magneticfield. This presentation will be based on a recent preprint (arxiv:1301.1706).

∗Work supported in part by the Natural Sciences and Engineering Research Council of Canada.†E-mail:[email protected]


PHYSICAL IMPLICATIONS OF THE TOPOLOGICAL CASIMIREFFECT∗

C. Cao†, M. van Caspel, A.R. ZhitnitskyDepartment of Physics & Astronomy, University of British Columbia

The Casimir effect is typically known as the presence of an attractive force between two neutrally charged and perfectlyconducting parallel plates in vacuum. It was known that an extra term in the Casimir energy emerges from non-trivialtopological features of the gauge fields, but this effect is greatly suppressed in the typical setup of Casimir effectexperiments. Nevertheless, I will show in this presentation that, unlike the conventional Casimir effect, this topologicaleffect is highly sensitive to external magnetic fields, which may serve as a distinctive feature for possible experimentalefforts. I will also discuss physical quantities such as pressure and induce field strengths unique to this topologicaleffect.



THE TRIUMF PIENU EXPERIMENT

D. vom Bruch∗

University of British Columbia

The PIENU collaboration

The PIENU experiment at TRIUMF aims to search for new physics by measuring the branching ratio of pionsdecaying to positrons and muons. The Standard Model predicts a value of R = 1.2352(2) · 10−4 for the branchingratio which represents a level of precision that has not been achieved by previous experiments. Mass scales for newphysics can be obtained by reaching a level of precision of less than 0.1%, which approaches an order of magnitudeimprovement over prior experiments. In this talk I will present the current status of the experiment and data analysis.

∗mail: [email protected]


A CLUSTER-COUNTING DRIFT CHAMBER FOR FLAVOUR PHYSICSEXPERIMENTS

Jean-Francois Caron∗

The University of British Columbia

Drift chambers are general-purpose particle detectors used to track and identify charged particles in high-energyphysics experiments, most recently in flavour-physics experiments. Charged particles passing through the drift cham-ber will ionize the gas, producing electron-ion pairs. The electrons will drift towards high-voltage sense wires arrangedin cells, picking up enough speed to further ionize the gas and create an avalanche. The avalanche of electrons on thesense wire is received as a signal.

Traditional drift chambers identify charged particles by integrating the total charge accumulated on sense wireswhen such a particle passes through the cells. The probability density function of deposited charge in a single cellis non-Gaussian and has a long tail towards high values, so a simple mean over all the cells is not useful. Instead a“truncated mean” is performed where the largest fraction (typically ∼ 30%) of the cells are discarded. The result isa useful Gaussian quantity with different mean values for particles of different masses. Unfortunately this proceduredoes not use the full information available in a track.

When a charged particle passes through a drift chamber, it ionizes the gas at particular locations. With properelectronics, the arrival of individual clusters of electrons on the sense wire can be resolved. The integrated charge froma traditional drift chamber is the sum of all of these clusters. Since the size of each cluster depends on many randomvariables (avalanche amplification, order of primary ionization), the resolution of the total integral is degraded. Ifinstead each cluster is resolved and counted, the number of clusters can be used to identify the particles. The probabilityof ionization (and thus the number of clusters) depends on the mass of the particle, but has less variation than the chargeintegral.

In this work, algorithms are developed and optimized which identify clusters on real drift chamber signals fromprototypes. The prototypes were subjected to a beam of electrons, muons, and pions at 200 MeV/c at TRIUMF in thesummer and fall of 2012.

The result is a remarkable enhancement in the ability to separate different species of particles. The techniquesinvolved are generic enough to be exploited by any drift chamber with the proper electronics.



S6 Nuclear and High-Energy

Astrophysics Chair: R. Kruecken (TRIUMF)


NUCLEOSYNTHESIS, HYDRODYNAMICS AND EVOLUTION OFSINGLE STARS, NOVA, AND WHITE DWARF MERGERS

Falk Herwig∗, Pavel Denisenkov, Athira Menon, Christian RitterDepartment of Physics and Astronomy, University of Victoria, Canada

Marco PignatariDepartment of Physics, University of Basel, Switzerland

Paul WoodwardLCSE, University of Minnesota, USA

Jim TruranJoint Insitute for Nuclear Astrophysics (JINA), University of Chicago, USA

Michael Bertolli, Chris FryerTheory Division and CCS Division, Los Alamos National Laboratory, USA

Raphael HirschiEPSAM, Keele University, UK

We summarize the most important nucleosynthesis channels in stars, including AGB stars and massive stars based onthe work of the NuGrid collaboration (http://www.nugridstars.org). Detailed models from 1.65M� to 60M�, includingsimplified supernova explosion models for the massive stars, are now available along with complete post-processingsimulations that provide abundance predictions of all isotopes. Using the tools of the NuGrid collaboration any ofour models (including those described below) can be analysed a posteriori for sensitivity with regard to any of theinput nuclear physics uncertainties. We will further discuss the particular evolutionary events encountered at very lowmetallicity. These require three-dimensional hydrodynamic simulation techniques to realistically model the non-linearinteraction between nuclear burning and convective mixing, and we demonstrate verification and validation of suchhydro simulations. In such environments high neutron densities of ∼ 1015cm−3 are encountered, and nuclear physicsdata approximately 3-6 mass numbers away from stability is needed, but poorly known. We have developed specialtechniques of correlated nuclear physics uncertainty propagation to maximize the possibility of comparing modelpredictions with observations, despite the present nuclear data uncertainies. Finally, we report on results from ourprojects related to the evolution and nucleosynthesis in binaries and post-merger objects. In our nova program† we havefor the first time succeeded to construct model sequences with convective boundary mixing that reproduce observedabundance patterns without assuming said abundance enhancements are already present in the accreted material. Ournova framework is capabable now to generate both CO and ONe nova models of high mass, and we have performeda survey of nuclear reaction rate uncertainties based on our nova models. While in the nova environment H-burningat high temperatures plays the most important role, the post-merger evolution of He + CO white dwarfs is dominatedby a wide range of α-capture reactions. Assuming that the reaction rates are known to sufficient precision the merger-induced mixing processes have been determined by matching observations of the highly peculiar abundance featuresof post-merger objects. All of these environments feature unusual nucleosynthethesis processes and have in commonthat nucleosynthesis is closely interacting with – and constraining – mixing.

∗E-mail: [email protected]†Supported by and in collaboration with TRIUMF.


ACCRETING WHITE DWARFS: A ONE-ZONE ANALYSIS OFNUCLEAR BURNING

S. Pillay, J. Matthews, J. HeylUniversity of British Columbia, Department of Physics and Astronomy

Accreting white dwarfs can exhibit a variety of thermonuclear phenomena such as nuclear shell flashes, classicaland recurrent novae outbursts, as well as Type Ia supernovae explosions. To better understand these processes, we con-sider the accretion of hydrogen-rich material onto the surface of a white dwarf. We use a one-zone model to describethe thin shell of accreted hydrogen enveloping the degenerate white dwarf core. Paczynski tackled this problem in1983. Following Paczynski’s approach, we make use of the standard stellar structure equations, assuming hydrostaticequilibrium, in plane-parallel geometry to model the hydrogen-rich layer. These equations, along with the appropriateboundary conditions, allow us to investigate nuclear burning. In steady state, these equations reduce to a system ofalgebraic equations, which we use to converge to a linear series of models by varying the accretion rate, or columndensity, for a fixed set of model parameters, namely, the chemical composition of the layer, surface gravity, and heatflux from the core. We present our model results and compare them to Paczynski’s.


FIRST DIRECT MEASUREMENT OF THE 18F(p,γ)19Ne REACTIONAND THE IMPLICATIONS FOR DETECTING 18F γ-RAY EMISSION

FROM NOVAE. ∗

C. Akers†, A.M. Laird, B.R. FultonDepartment of Physics, University of York, York, YO10 5DD, United Kingdom

C. Ruiz, L. Buchmann, G. Christian, B. Davids, J. Fallis, L. Martin, D. Ottwell, A. RojasTRIUMF, Vancouver, British Columbia, V6T 2A3, Canada

D.W. BardayanOak Ridge National Laboratory, Tennessee, 37831, USA

L. EriksonPacific Northwest National Laboratory, Washington, 99354, USA

U. HagerColarado School of Mines, Colorado, 80401, USA

A.St.J. MurphySUPA, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ,

United Kingdom

K. NelsonMcMaster University, Hamilton, Ontario, L8S 4L8, Canada

A. SpyrouDepartment of Physics & Astronomy, Michigan State University, East Lansing, Michigan, 48824,

USA

C. StanfordUniversity of Waterloo, Ontario, N2L 3G1, Canada

The rate of the 18F(p,γ)19Ne reaction is thought to affect the final abundance of the γ-ray observable radioisotope,18F,produced in novae. Although the current uncertainty in this rate can change the final abundance of 18F by up to a factorof ten, this reaction has never been successfully measured directly. Of the two resonances thought to play a signifi-cant role, one has radiative widths estimated from the assumed analogue state in the mirror nucleus, 19F. The seconddoes not have an analogue state assignment so this information is lacking. Here we report the first successful directmeasurement of the 18F(p,γ)19Ne reaction. The strength of the 665 keV resonance (Ex = 7.076 MeV) is found to beover an order of magnitude weaker than currently assumed in nova models. Reaction rate calculations show that thisresonance is now expected to play no significant role in the destruction of 18F at any astrophysical energy.

∗Work supported by the Natural Sciences and Engineering Research Council of Canada†E-mail: [email protected]


THE R-PROCESS NUCLEOSYNTHESIS CODE, R-JAVA 2.0M. Kostka∗, R. Ouyed, N. Koning

University of Calgary

In this talk I will introduce the latest release of the r-process nucleosynthesis code, r-Java 2.0. The aim of developingthis code is to provide robust and cutting-edge r-process software that is simple to use across all platforms. Thegraphical user interface provides the user with numerous ways of viewing r-process results as well as the abilityto plot temperature dependent rates. While the main use for r-Java 2.0 is to run r-process simulations, the code isas well able to explore nuclear statistical equilibrium as well as fission. R-Java 2.0 is capable of solving the fullr-process reaction network considering; neutron capture, photo-dissociation, alpha processes, beta-decay and betadelayed neutron emission. Included in r-Java 2.0 is a thorough treatment of fission accounting for; spontaneous, beta-delayed and neutron-induced fission channels. In this talk I will present bench-marking tests done on r-Java 2.0 againstother r-process codes. The effect of including a full treatment of fission in the r-process calculation against the often-used maximum mass approach will as well be discussed. Finally I will touch upon the ability of r-Java 2.0 to simulatespecific r-process sites such as; the high-entropy winds surrounding a proto-neutron star, neutron star mergers andquark novae ejecta.



THE EFFECT OF BETA-DELAYED NEUTRON EMISSION ONR-PROCESS ELEMENTS PRODUCED IN THE HIGH ENTROPY WIND

OF A SUPERNOVA

Z. Shand, M. Kostka, R. OuyedUniversity of Calgary

The r-process (rapid neutron capture) following an explosive astrophysical event is believed to be responsible forthe production of the heavy elements we observe in the galaxy and our solar system. Using r-Java this process wasmodeled to determine the required environment for producing the observed isotopic abundances to determine theorigin of the heavy elements in the galaxy. In particular, the conditions required to reproduce the observed abundancepeaks near mass numbers 80, 130 and 190 were studied. This is of interest because it not only provides an explanationfor the source of the elements we see today, but can also be used in the study of both high energy astrophysics andexperimental nuclear physics measurements.

The high entropy wind of a core collapse supernova provides a candidate for r-process elements to be produced.Beginning with the results of charged particle network calculations performed by others (Farouqi 2010, Woosley1998), the r-process calculations were carried out. The abundance patterns calculated depended most strongly on thenumber of available neutrons to be captured; however, both the temperature and density profiles affected the resultsof the calculation. The location of the peaks near mass numbers 80, 130 and 190 were found to be dependent on theinput parameters: initial abundance, temperature, expansion velocity and number of neutrons.

In addition to the conditions required to produce these three peaks, the exact location of these peaks followingthe r-process was also studied and found to be dependent on not only the astrophysical environment, but also nuclearphysics. Because the nuclei produced are neutron rich, beta-delayed emission is an important nuclear process. Beta-delayed neutron emission both re-introduces neutrons for recapture and changes the mass number of the producednuclei. Using r-Java, the effect of beta-delayed neutrons was examined and found to affect the overall abundancedistribution and the locations of the abundance peaks.

Following charged particle networks which produced seed nuclei beyond the iron group, all three abundance peakswere successfully observed; however, no single set of parameters was able to reproduce all three peaks as we observethem in the galaxy.


NUCLEOSYNTHESIS CAUSED BY THE COLLISION OF ADETONATING NEUTRON STAR’S EJECTA WITH THE SUPERNOVA’S

EJECTA∗

Amir Ouyed†,Rachid Ouyed, Denis LeahyUniversity of Calgary

Current models depict that a star that explodes through a supernova (SN), will leave behind either a black hole ora neutron star. However, we propose an alternative, evolutionary channel wherein this neutron star can also detonate(Quark-Nova or QN). The QN ejects energetic particles, including heavy nuclei and ultra-relativistic neutrons. Theenergetic QN ejecta collides with the SN ejecta of the prior star’s explosion, generating nuclear reactions, and thus,daughter isotopes. This nucleosynthesis can resolve some theoretical issues in astronomy, including the overproductionof 44Ti by current SN models. Furthermore, the daughter isotopes yield photometric and spectroscopic signals thatwould aid in discriminating QN signatures from other observed, astronomical objects.

∗Work supported by the Natural Sciences and Engineering Research Council of Canada†E-mail: [email protected]


GALACTIK : A CHEMICAL EVOLUTION CODE

M. Tahani∗, A. Sourie, N. Koning, R. OuyedDepartment of Physics & Astronomy, University of Calgary, 2500 University Drive NW, Calgary,

AB T2N 1N4, Canada

Galactic Chemical Evolution (GCE) studies are the key point to understand stellar nucleosynthesis and the historyof star formation in galaxies. GCE studies are aimed to find correlation between elemental abundances with parameterslike time, location within a galaxy, and stellar velocities. The Quark Nova Group at the University of Calgary hasdeveloped a GCE code, named as ”GalactiK”, to better understand these correlations. GalatiK is an openly sharedcross-platfom program where any interested researcher can study the evolution of specific nuclear elements over thelife of the galaxy.

In this talk, I will briefly discuss the GCE model which GalactiK is based on, and will talk about different options,which can be changed in the model, like choosing different Initial Mass Functions (IMF), infall rates, Star FormationRate (SFR), and etc.

At the end, I will show some of the GalactiK results and will compare them with the observations and with theresults from different papers.



COMBINED ANALYSIS OF X-RAY SPECTRA OF THE SOUTHWESTCYGNUS LOOP DETECTED BY SUZAKU AND XMM-NEWTON

OBSERVATORIES ∗

Mohammed Hassan†, Denis Leahy


The surrounding interstellar medium (ISM) of supernova remnants (SNRs) usually show inhomogeneities thatappear as a bright features in X-rays which attributed to a blast wave collision with a set of interstellar (or circumstellar)clouds. In the current work, a detailed spectral analysis of the so-called ”V” feature in the southwest rim of the CygnusLoop is presented. This region has been observed by bothSuzaku and XMM-Newton observatories which allowsus to carry out a joint spectral analysis of the Cygnus Loop using data from bothSuzaku andXMM-Newton camerascombined. The spectral analysis shows that all of the spectra are well fitted by a non-equilibrium ionization model withvariable abundances (VNEI) or a two-component VNEI model. From the best-fit parameters electron temperatures andionization timescales are found to be inversely related, consistent with an origin in density variations by a factor of∼ 3. Element abundances and temperature are strongly correlated, which can be explained by mixing in the outerhydrogen-rich envelope of ejecta: heavy-element-rich regions have higher velocity to reach this far out from the centerof the Cygnus Loop, resulting in higher shock temperature for more element-rich regions.

Subject headings: ISM: abundances ISM: individual (Cygnus Loop) supernova remnants X-rays: ISM



DISENTANGLING THE COMPLEX ENVIRONMENT OF THE GAMMACYGNI SUPERNOVA REMNANT∗

K. Green†, D. Leahy, S. Ranasinghe


We examine the atomic hydrogen (HI) line and radio continuum data from the Canadian Galactic Plane Survey toyield a new HI absorption distance to supernova remnant gamma Cygni (G78.2+2.1) with a corresponding HI columndensity.

We present new x-ray images of the supernova remnant G78.2+2.1 using ROSAT survey and Chandra and ROSATpointed observations. The association of the non-thermal radio emission from the remnant with the corresponding x-ray shells is discussed. The high (spectral and spatial) resolution Chandra data is used to study the nature of G78.2 andof a second overlapping x-ray shell, previously believed to be associated with G78.2+2.1. We also examine sources ofhard x-ray emission previously thought to coincide with the remnant.



SULFUR BEARING SPECIES IN THE ORION SOUTH MOLECULARCLOUD REGION

Fatima Garcia⇤,University of Calgary

Supervisor: Dr. Rene PlumeUniversity of Calgary

An emission line study was conducted on the Orion South Region. Volatiles such as sulfuretted molecules andcompounds make important stellar clocks, as these reflect the physical conditions of the system in which they arefound. The Orion South region is of particular importance as it represents a younger evolutionary stage of the Orion-KL region. Study of the simpler, younger, southern region is expected to yield information about the processes, ageand composition of the more complex Orion-KL region and how massive star formation regions evolve chemically.

Spectra gathered using the Herschel Space Telescope HIFI instrument was analyzed using the freely availableCASSIS spectral analyzer software package. This project aimed at determining the conditions necessary for severalsulfur bearing molecules, particularly 12C32S and 12C 34S to emit at the observed intensities. Specific conditions wereexplored in both the hot core and the cold envelope regions of Orion South, and analyzed to determine whether theywere in the local thermodynamic equilibrium (LTE) or in non-LTE regimes.

In the hot core the controlled parameters were: temperature, column density and cloud size; the cold envelopecomponent, the temperature, column density and the molecular density were varied. The convergent models returneda column density of 3.20E14 cm�2, a temperature of 80K and a size of 15” for the hot core component and a columndensity of 9E14, a temperature of 37.5K and a hydrogen density of 4E7 cm�3 for the cold envelope component.

From the values returned by the models, the mass of the cloud was calculated from both a surface area approach(column density based) and a volume approach (hydrogen density). The calculations returned masses of 615M� and61M� respectively, a discrepancy that was accounted for in the method of calculation. The analysis returned densityvalues that were higher than expected, and discovered that, contrary to expectation, the cold envelope was in the non-LTE transfer regime, but very close to LTE excitation conditions, implying that LTE models can be used to describethe cloud.

⇤E-mail:[email protected]


S7 Dark Matter

Chair: R. Ouyed (University of Calgary)


THE CASE FOR DARK MATTER AS A NEW ELEMENTARYPARTICLE∗

Itay Yavin†,

Much of the matter in the universe is missing from our account of the basic particles and forces in the universe.What is dark matter? In this talk I will review the case for dark matter as a new elementary particle. I will discuss threemajor efforts aiming at its detection: current world-wide efforts to detect dark matter’s collisions with normal matterin the laboratory; searches for dark matter production in high energy colliders such as the LHC; and searches for darkmatter annihilation in the galaxy. Each of these efforts is pushing the boundaries of our knowledge of particle physicsand the basic interactions of nature. I will end with a brief mention of other ideas and approaches to the dark matterproblem.



DARK MATTER SEARCHES USING THE ICECUBE NEUTRINOOBSERVATORY

T. R. Wood∗, for the IceCube CollaborationUniversity of Alberta

The IceCube Neutrino Observatory instruments a cubic kilometre of glacial ice below South Pole Station, Antarc-tica, creating a large scale water Cherenkov detector. With the addition of the low energy in-fill extension, DeepCore,completed in 2010, the observatory is sensitive to neutrinos with energies between 10 GeV and 1 EeV. This broad en-ergy range provides a new window to study the very high energy neutrinos produced in the most violent astrophysicalprocesses (including gamma ray bursts and active galactic nuclei), as well as the annihilation or decay of low-massdark matter candidates. With it’s vast size and very high neutrino detection efficiency, IceCube has great discoverypotential. Discussed will be the most recent limits from the observatory’s indirect dark matter searches.



Posters


DEMONSTRATION OF GALACTIK; A CHEMICAL EVOLUTIONCODE.

N. Koning∗, M. Tahani, A. Sourie, R. OuyedDepartment of Physics & Astronomy, University of Calgary, 2500 University Drive NW, Calgary,

AB T2N 1N4, Canada

The capability of computers today allows for the development of extremely complex codes. Unfortunately, an in-crease in complexity is often followed by a decrease in usability. These codes are routinely private and are inaccessibleto the general community. The ones that are available are so complex that only the authors understand their use. As aresult, codes are being developed over and over which perform essentially the same task, wasting valuable time andresources.

It is a goal of the Quark Nova Project at the University of Calgary to help alleviate this problem by developingeasy to use codes accessible to the general community. Our latest endeavour, GaLaCTiK, is a Galactic ChemicalEvolution (GCE) code designed to study the chemical evolution of our Galaxy. The software was created in Java,thereby providing an easy to use graphical user interface (GUI) available to all computer platforms. In this talk I willbe giving a short demonstration on the use of GaLaCTiK.



NEW VIEWS OF HERCULES X-1 FROM 15 YEARS OF RXTEOBSERVATIONS ∗

D. Leahy†,University of Calgary, Calgary, Canada

The X-ray binary Hercules X-1 displays a variety of phenomena, including pulsations at 1.24 s, eclipses at theorbital period of 1.7 days, and a 35 day cycle in the X-ray intensity. Yet the intrinsic properties of the system, such asthe geometry of the accretion disk, disk corona and accretion stream are poorly understood. The 35-day cycle is causedby a precessing accretion disk which gives time-varying blockage of X-rays from the neutron star, but the mechanismsfor absorption dips and of the anomalous low state are not yet known. Here, results from 15 years of RXTE/PCAobservations are reviewed and new results are presented. The observations give important clues on the properties ofthe dips and anomalous low states. A new analysis of X-ray eclipse gives the size and density of the accretion diskcorona for the first time.



THE PREX AND CREX EXPERIMENTS∗

J. Mammei†

University of Manitoba

For the PREx II and CREx Collaborations

The structure of neutron stars, from the thickness of their crust to their maximum size, depends on the equationof state (EOS) of neutron matter. The “neutron skin” (the difference between the RMS of the density distributions ofneutrons and protons) of neutron-rich nuclei such as lead and calcium can tell us about the EOS of neutron matter. Thesize of the neutron skin has implications for nuclear astrophysics, atomic parity violation and nuclear structure. Twoexperiments at Jefferson Lab, located in Newport News, VA, plan to measure the neutron radius of lead and calciumwith a precision of 1% by exploiting the property of parity violation in the weak interaction. The Pb and Ca RadiusExperiments (PREx II and CREx) will measure the RMS weak charge radius of these nuclei using parity-violatingelastic electron-nucleus scattering. Combining the results with the well-known charge radii of these nuclei providesa measurement of the neutron skin which is free from many of the strong interaction uncertainties that are present inother measurements. Results from the initial run of PREx and status of the future experiments will be presented.

∗Work supported by the US DOE Office of Science, Office of Nuclear Physics, Jefferson Science Associates, and the University of Manitoba†E-mail: [email protected]


ULTRACOLD NEUTRONS AT TRIUMF∗

R. R. Mammei†

University of Winnipeg

RCNP/KEK/TRIUMF UCN collaboration

Ultracold neutrons are neutrons that have been cooled below 3 mK. At this temperature they travel at a speed lessthan 8 m/s and exhibit the peculiar behavior of being stored in magnetic, material, and gravitational bottles for periodsranging up to their beta-decay lifetime (∼15 min). They present a new avenue for performing fundamental neutronexperiments such as: searching for a non-zero neutron electric dipole moment, precise measurement of the neutronlifetime, and precise measurements of neutron beta decay correlation coefficients to name a few. These measurementshave important consequences for extensions to the standard model of particle physics which may explain the baryonasymmetry of our universe.

In the past, UCN were obtained by cooling neutrons from fission based nuclear reactors. However over the last 15years several new sources of UCN, called super thermal sources, have been pioneered. Here spallation neutrons arecooled by cryogenic convertors and afford UCN densities many orders of magnitude over reactor based systems. Onesuch super thermal source based on conversion in superfluid helium is being developed by RCNP (Japan) and TRIUMF(Canada) and will be used to make a new measurement of the neutron electric dipole moment. I will provide anoverview of the rich physics opportunities available to UCN experiments and the current status of the RCNP/TRIUMFUCN source and neutron electric dipole experiment.

∗Work supported by the Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation, Japan Society forthe Promotion of Science, and KEK High Energy Accelerator Research Organization.



NUMERICAL SIMULATIONS OF THE TRANSITION TO U,D,S QUARKMATTER

B. Niebergal∗, R. Ouyed


P. Jaikumar

University of California Long Beach

Thedynamical behaviour of the transition from hadronic to quark matter is governed by equations that lend them-selves poorly to analytical solutions, hence computational methods must be employed. I have developed a computercode (BURN-UD) that solves the equations of hydrodynamical burning and applied it to the phase transition, specif-ically as it occurs in the centers on compact stars. By running simulations that model the birth of a strange quark starI have determined some physical properties of the transition, most importantly the burning speed, which was foundto be much faster than expected. Another unexpected result involves the effects of self-consistently including neu-trino cooling, which can lead to a what we call adeleptonization instability. This instability can have a large range ofconsequences including entirely quenching the transition, or, given the right conditions it can corrugate the transitioninterface leading to an enhanced burning and possibly detonation.

These results are new and exciting, but more sophisticated numerical work is required to verify the findings ina realistic multi-dimensional setting. If these results prove valid, the consequences include the determination of themanner in which au,d,s-quark star is born as well as provide strong evidence that the phase transition to quark matteris responsible for many highly-energetic astrophysical phenomena.

Additional applications of the BURN-UD code include the study of the quark matter phase transition in the earlyUniverse, as well as in heavy-ion collision experiments where signs of deconfined quark matter are starting to be seen.We anticipate exciting results, especially due to consequences of our newly discovered deleptonization instability.



ABSOLUTE CROSS SECTION MEASUREMENTS OF THE 3He(α,γ)7BeREACTION USING THE DRAGON RECOIL SEPARATOR

A. Rojas∗ for the DRAGON collaborationTRIUMF, Vancouver British Columbia V6T 2A3, Canada

Current uncertainties in the reaction rate of the nonresonant 3He(α,γ)7Be capture represent a leading source of system-atic uncertainty in solar neutrino flux estimations. Over the last five decades, significant theoretical and experimentalefforts have increased the precision of the adopted 3He(α,γ)7Be reaction rate at relevant astrophysical energies. Nev-ertheless, for energies Ecm & 1.5 MeV, important to test the extrapolation using available models, the data are sparserand in some cases contradictory. The DRAGON collaboration at TRIUMF is carrying out ongoing measurements ofthe 3He(α,γ) absolute cross section using a recoil separator. In this talk, a concise account of the analysis of recentdata from the collaboration will be presented and theoretical model implications will also be discussed.



A NEW REACTION SPECTROSCOPY FACILITY IRIS AT TRIUMF

A. Sanetullaev1,2∗, R.Kanungo1, S. Ishimoto3, I. Tanihata4, P. Fortier1, J. Tanaka4, S. Suzuki3, G.Sheffer2, R. Openshaw2, R. Henderson2, G. Hackman2, P.A. Amaudruz2, A. Shotter5,2, C.

Andreoiu6, A. Chen7, G. Christian2, B. Davids2, A.T. Gallant8,2, N. Galinski9,2, D.A. Howell9,2, J.Fallis2, O. Kirsebom2, R. Kruecken2, J. Lighthall2, S.T. Manwell7, P. McLeod1, D. Miller2, A.

Rojas2, H. Savajols10, C. Trottier1, C. Unsworth2, P. Voss6,2, Z. Wang6,2

1Department of Astronomy and Physics, Saint Marys University, Halifax , Nova Scotia B3H3C32TRIUMF, Vancouver, British Columbia V6T2A3

3High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan4RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan

5School of Physics and Astronomy, University of Edinburgh, Edinburgh, U.K.6Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S67Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S4M1

8Department of Physics and Astronomy, University of British Columbia, Vancouver, BritishColumbia V6T 1Z1

9Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S610GANIL, Boulevard Henri Becquerel, Bote Postale 55027, F-14076 Caen Cedex 05, France

The ISAC Charged Particle Reaction Spectroscopy Station, IRIS, is a new experimental facility at TRIUMF that willenable investigations of very neutron and proton-rich nuclei through direct nuclear reactions. The one-neutron transferreactions allow us to study the internal structure of the unknown exotic nuclei and inelastic scattering is used to findnew excited states and study the excitation mechanism.

An innovative feature of IRIS is the use of thin solid hydrogen target in order to maximize the number of in-teractions with low rate rare-isotope beams at TRIUMF. Another important development is the use of low pressureionization chamber to measure the energy loss and identify the charge of the the incoming beam particles beforethe target. This will help identify the isobars in the beam. After the reaction it is crucial to measure the energy andscattering angle of both the the target-like light particle and the beam-like heavy particle. The light particles will bedetected in Si detectors of Micron YY1 design, backed by thick CsI(Tl) detectors to form a ∆E − E telescope. Theheavy particles will be detected in two layers of Si detectors of Micron S3 design of different thicknesses that form a∆E − E telescope.

The facility was recently commissioned with stable beams of 18O and 40Ar. The presentation will outline the IRISfacility and show results of the successful implementation of the solid hydrogen target which is a pioneering effort inlow-energy reaction studies of rare isotopes.



Jose Edua r do Vi l l a r r e a l -Ba ra j a s - U of C€¦s4d 12:00 dilli raj paudyal measurement...

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