ICHEP '06 Observation of the GZK Cutoff by the HiRes Experiment Gordon Thomson Rutgers University.
Results from HiRes and Observation of the GZK Suppression Kai Martens High Energy Astrophysics...
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Transcript of Results from HiRes and Observation of the GZK Suppression Kai Martens High Energy Astrophysics...
Results from HiResand Observation of the
GZK Suppression
Kai Martens
High Energy Astrophysics Institute
Department of Physics, University of Utah
for the HiRes Collaboration
HR1HR2
August 7, 2007 Kai Martens, University of Utah, @ ISMD 2
Outline:- Short Introduction to Cosmic Rays
- The HiRes Experiment- Monocular Observation:
- Going to Extremes- Evidence for GZK Suppression
- Stereo Observation: - Checks and Balances- HiRes Composition Measurement
- Interpretation: - Ankle, Cutoff, and Cosmogenic Neutrinos- HiRes Neutrino Limits
- In Search of the Sources:- Anisotropy- Correlations
- Conclusions
August 7, 2007 Kai Martens, University of Utah, @ ISMD 3
Cosmic Rays
GeV TeV PeV EeV
(m2 s
r s
GeV
)-1
10-28
102
1km2 y/
Power laws for Flux: J~E
<3 PeV: =2.7~3 PeV: Knee>3 PeV: =3.0
Swordy Plot:
knee
ankle
August 7, 2007 Kai Martens, University of Utah, @ ISMD 4
Air Shower Dimensions
Fluorescence Detector:longitudinal profilethroughout atmosphere
Ground Array:transverse profileat ground level
Cosmic Ray showers - start at ~ 15 km above ground- span a couple of km across- hundreds of billions of particles
thick water tanks thin scintillators
1019 eV
(e/m + ) (e/m only)
August 7, 2007 Kai Martens, University of Utah, @ ISMD 5
The HiRes Experiment:
12.6 km apart
HR2: 12/199942 mirrors
3-31 elevationFADC (100ns)
DugwayProvingGrounds
HR1: 5/199719 mirrors
3-17elevationSample&Hold
Delta
HiRes on DPG:
August 7, 2007 Kai Martens, University of Utah, @ ISMD 6
HiRes Optics:
Mirror surface 5.1 m2
Field of view: 16 x 14
Camera:16 x 16
PMTeach sees
1o x 1o
in sky
SUN:½o
UV filter !!!(protecting PMTs)
low resolutionhigh speed
August 7, 2007 Kai Martens, University of Utah, @ ISMD 7
HiRes: Stereo!!!July 11, 1999; Energy: 19 EeV
Light Propagation:
Atmosphere HR1
HR2
HR2HR1
Dugway Proving Ground
August 7, 2007 Kai Martens, University of Utah, @ ISMD 8
The Collaboration:S. BenZvi, J. Boyer, B. Connolly, C.B. Finley, B. Knapp, E.J. Mannel, A. O’Neill, M. Seman, S. Westerhoff
Columbia University
J.F. Amman, M.D. Cooper, C.M. Hoffman, M.H. Holzscheiter, C.A. Painter, J.S. Sarracino, G. Sinnis, T.N. Thompson, D. Tupa
Los Alamos National Laboratory
J. Belz, M. Kirn
University of Montana
J.A.J. Matthews, M. Roberts
University of New Mexico
D.R. Bergman, G. Hughes, D. Ivanov, L. Perera, S.R. Schnetzer, L. Scott, S. Stratton, G.B. Thomson, A. Zech
Rutgers University
N. Manago, M. Sasaki
University of Tokyo
R.U. Abbasi, T. Abu-Zayyad, G. Archbold, K. Belov, A. Blake, O. Brusova, Z. Cao, W. Deng, W. Hanlon, P. Huentemeyer, C.C.H. Jui, E.C. Loh, K. Martens, J.N. Matthews, D. Rodriguez, K. Reil, J. Smith, P. Sokolsky, R.W. Springer, B.T. Stokes, S.B. Thomas, L. Wiencke
University of Utah
Z. Cao, B. Zhang, Y. Zhang, Y. Yang
IHEP Bejing
August 7, 2007 Kai Martens, University of Utah, @ ISMD 9
Challenge: (Mono) Reconstruction
angle along horizon
ang
le a
bo
ve h
ori
zon
In-plane Angle (deg)
Tim
e (1
00
ns)
angle in plane
Tim
e to
co
mm
on
sto
p
amount of matter (air) traversed
Ph
oto
elec
tro
ns
at d
etec
tor
light curve+
atmosphere=
energy
Reconstruction steps:
1. shower detector plane 2. Shower axis (full geometry)3. fluorescence light curve
(FADC !!!)
August 7, 2007 Kai Martens, University of Utah, @ ISMD 10
HiRes Monocular Spectra
flux x E3
HR1: longer exposure high energy
HR2: larger elevation coverage low energy
energy scale uncertainties:
- missing energy 5%- energy loss rate 10%- fluorescence yield 6%- atmospheric conditions 4%- photometric calibration10%
total (energy): 17%
flux uncertainty: 30% (@ =2.8)
data:HR1: 5/97-6/05HR2: 12/99-8/04
August 7, 2007 Kai Martens, University of Utah, @ ISMD 11
HR1: Aperture Verification - Data vs. MC
August 7, 2007 Kai Martens, University of Utah, @ ISMD 12
HR2: Aperture Verification - Data vs. MC
August 7, 2007 Kai Martens, University of Utah, @ ISMD 13
GZK Suppression: ? !!
Old plots:AGASAAGASA (E–20%)
avoid double counting:remove HR1 events that also
are in the HR2 data set
Broken power-law fits:a.) one vs. two breakpoints:
2 reduced by 23.4 4.5
b.) compare measured data to red line extrapolation:expect: 39.9observe: 13 4.8 (P=7x10-7)
Quacks like duck, don’t
it?
August 7, 2007 Kai Martens, University of Utah, @ ISMD 14
Stereo Observation
full stereo analysis ongoing; shown: geometry from HR1/HR2plane intersect, light curve from HR2 data only:
stereo advantages: geometry constraint (!!!), light balance check on atmosphere
energy balance:Xmax
resolution: 30g/mc2
August 7, 2007 Kai Martens, University of Utah, @ ISMD 15
Composition from Stereo DataXmax distributions:
datavs.
proton
datavs.iron
Xm
ax [g
/cm
2 ]
Xmax [g/cm2]
18 20
log10(E/eV)
Fe + p | (mostly) p
data: HRprototype
HiRes stereodata: ~ 80% p
MC: p
MC: Fe
galactic extra-galactic
August 7, 2007 Kai Martens, University of Utah, @ ISMD 16
Interpretation of HiRes monocular CR:
Doug Bergman, Rutgers(following Berezinsky)
Fit interprets spectrumin terms of
extragalactic protonsthat traveled from
cosmological sources
changed interpretation of ankle:
galactic/extragalactic transition: composition change vs. slope change
p+ (1232) +N
+
e + e +
composition change slope change
p+ p+e++e- redshift
energy
flu
x
propagation:protons
only
August 7, 2007 Kai Martens, University of Utah, @ ISMD 17
ee
eepn
HiRes Composition Guided Fits fluxsource model:
all sources inject with E
= 2.42uniform with redshiftevolution (1+z)m
m = 2.46
future: astronomy inspired redshift evolution
composition as measured !
August 7, 2007 Kai Martens, University of Utah, @ ISMD 18
The HiRes Neutrino Limits:
90% CL, uncertainty MC statistics only
MC injection: E-2 spectrum
e limits (no topography):1018 – 1019: 3820 ±1201019 – 1020: 3260 ±801020 – 1021: 4250 ±100
event distinguishing features: - horizontal !!! - close to ground
target mass: rockdetector volume: air
e LPM -lepton
limits:1018 – 1019: 420-20
+25
1019 – 1020: 1340-110+140
1020 – 1021: 29400-8900+22100
fluxes as derived from
HR spectrum fit
August 7, 2007 Kai Martens, University of Utah, @ ISMD 19
MC: Topology at Work interaction points for decaying above ground:Cedar Mtns
Deep Creek Rng
Stansbury Mtns Oquirrh Mtns
Fish Springs Rng Thomas Rng
Sheeprock Mtns
90 95
zenith angle in
HR system:
August 7, 2007 Kai Martens, University of Utah, @ ISMD 20
Anisotropy and ClusteringHR2 Sky Map:Sky Map: non-uniform exposure… use MC & on-time database to estimate uniform exposure
Point Sources:Point Sources:AGASA for E > 40 EeV: 5 doublets, 1 tripletHiRes stereo +AGASA: 28% of MC > tripletHiRes: E > 30 EeV: triplet + 1
Looking for Accelerators:Looking for Accelerators: BL lacTinyakov, Tkachev, Gorbunov analysis:
Vernon 9th, m<18, AGASA+Yakutsk: E>48 (24) EeV P=10-4
Vernon 10th, BL criteria differ, HiRes: E>10 EeV P=10-3
HiRes analysis (all events): 0.02%
the jury is still out: more data
Findings:- no global dipole- deficit at Galactic Anticenter??? (3.4)
August 7, 2007 Kai Martens, University of Utah, @ ISMD 21
Fixed Target Experiment @ 31018eV
HiRes 2007
mbsysstatAirpin )(11)(14460 HiRes:
meanenergy:
~ 1018.5 eV
“protons”selected
Xmax
Data:
August 7, 2007 Kai Martens, University of Utah, @ ISMD 22
Now Commissioning: Telescope Array
TA
3 x 120 degfluorescencetelescopes
MCCRCDelta, UT
2h from SLC
512 x 3m2
scintillatorarray
August 7, 2007 Kai Martens, University of Utah, @ ISMD 23
Conclusions• HiRes has finished taking data• HiRes has changed the cosmic ray (CR) landscape:
- extragalactic CR mostly protons- GZK suppression present in data + resonance- ankle likely e+e-, not transition to extragalactic…
spectral features important TALE• HiRes finds no significant UHE-CR anisotropies• HiRes finds no significant UHE-CR clustering• Correlations with astrophysical sources: jury still out• Ultra High Energy (UHE) CR research is alive in Utah:
Come and join our efforts for TA/TALE www.telescopearray.org
August 7, 2007 Kai Martens, University of Utah, @ ISMD 24
HiRes & Auger Limits