E06 · 2014. 11. 24. · Title: E06 Created Date: 11/24/2014 8:28:34 AM
Jefferson Lab E06-010 Collaboration Institutions CMU, Cal-State LA, Duke, Florida International,...
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Jefferson Lab E06-010 CollaborationInstitutions
CMU, Cal-State LA, Duke, Florida International, Hampton, UIUC, JLab, Kharkov, Kentucky, Kent State, Kyungpook National South Korea, LANL, Lanzhou Univ. China, Longwood Univ. Umass, Mississippi State, MIT, UNH, ODU, Rutgers, Syracuse, Temple, UVa, William & Mary, Univ. Sciences & Tech China, Inst. of Atomic Energy China, Seoul National South Korea, Glasgow, INFN Roma and Univ. Bari Italy, Univ. Blaise Pascal France, Univ. of Ljubljana Slovenia, Yerevan Physics Institute Armenia.
Collaboration members K. Allada, K. Aniol, J.R.M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P.C. Bradshaw, P.
Bosted, A. Camsonne, M. Canan, G.D. Cates, C. Chen, , J.-P. Chen (Co-SP), W. Chen, K. Chirapatpimol, E. Chudakov, , E. Cisbani(Co-SP), J. C. Cornejo, F. Cusanno, M. M. Dalton, W. Deconinck, P.A.M. Dolph , C. de Jager, R. De Leo, X. Deng, A. Deur, H. Ding, C. Dutta, C. Dutta, D. Dutta, L. El Fassi, S. Frullani, H. Gao(Co-SP), F. Garibaldi, D. Gaskell, S. Gilad, R. Gilman, O. Glamazdin, S. Golge, L. Guo, D. Hamilton, O. Hansen, D.W. Higinbotham, T. Holmstrom, J. Huang, M. Huang, H. Ibrahim, M. Iodice, X. Jiang (Co-SP), G. Jin, M. Jones, J. Katich, A. Kelleher, A. Kolarkar, W. Korsch, J.J. LeRose, X. Li, Y. Li, R. Lindgren, N. Liyanage, E. Long, H.-J. Lu, D.J. Margaziotis, P. Markowitz, S. Marrone, D. McNulty, Z.-E. Meziani, R. Michaels, B. Moffit, C. Munoz Camacho, S. Nanda, A. Narayan, V. Nelyubin, B. Norum, Y. Oh, M. Osipenko, D. Parno, , J. C. Peng(Co-SP), S. K. Phillips, M. Posik, A. Puckett, X. Qian, Y. Qiang, A. Rakhman, R. Ransome, S. Riordan, A. Saha, B. Sawatzky,E. Schulte, A. Shahinyan, M. Shabestari, S. Sirca, S. Stepanyan, R. Subedi, V. Sulkosky, L.-G. Tang, A. Tobias, G.M. Urciuoli, I. Vilardi, K. Wang, Y. Wang, B. Wojtsekhowski, X. Yan, H. Yao, Y. Ye, Z. Ye, L. Yuan, X. Zhan, Y. Zhang, Y.-W. Zhang, B. Zhao, X. Zheng, L. Zhu, X. Zhu, X. Zong.
Neutron Transversity: Current Status and the Future
Xin Qian Kellogg Radiation Lab
Caltech
Transverse Momentum Dependent
PDFs
TMD
Nucleon Spin
QCD Dynamics
Quark OAM/Spi
n
QCD Factorizatio
n
3-D Tomograph
y
Lattice QCD
Models
TMD f1
u(x,kT)
Quark polarization
Unpolarized(U)
Longitudinally Polarized (L)
Transversely Polarized (T)
Nucleon Polarization
U
L
T
Leading-Twist TMD PDFs
f1 =
f 1T =
Sivers
Helicity
g1 =
h1 =Transversity
h1 =
Boer-Mulders
h1T =
Pretzelosity
g1T =
Worm Gear
h1L =
Worm Gear(Kotzinian-Mulders)
: Survive trans. momentum integration
Nucleon Spin
Quark Spin
Separation of Collins, Sivers and pretzelocity effects through angular dependence
1( , )
sin( ) sin( )
sin(3 )
l lUT h S
h SSiverCollins
Pretzelosi
UT
tyU
sUT h S
h ST
N NA
P N
A
A
N
A
1
1 1
1
1 1
sin( )
sin(3 )
sin( )Co
PretzelosityU
SiversUT
llins
T h S T
h S
UT
UT h S
TU
UT
TA
H
f
A
D
A h H
h
N
q q
N
Helicity state
Rich Physics in TMDs (Transversity)
Some characteristics of transversity h1T = g1L for non-relativistic quarks No gluon transversity in nucleon Soffer’s bound
|h1T| <= (f1+g1L)/2 Violation of Soffer bound due to QCD confiment? J. P. Ralston arxiv:0810.0871
Chiral-odd → difficult to access in inclusive DIS Tensor Charge: Integration of transversity over x.
Calculable in LQCD
Parton Distributions (CTEQ6)
(Torino)
Unpolarized
Helicity
Transversity
Rich Physics in TMDs (Sivers Function)• Correlation between nucleon spin with quark orbital
angular momentum
Burkhardt : chromodynamic lensing
Final-State-InteractionYD
qTSIDIS
qT ff
11Important test forFactorization
11 DfA TSivers
Experiments on polarized ``neutron’’ urgently needed!!
)9
2()
9
4()
9
1()
9
1()
9
4(
)9
1()
9
8()
9
1()
9
4()
9
4(
..
pp
SC
nnn
ppppp
uddduN
duduuP
u quark dominated
Sensitive to d quark
)( du )( du
duudunfav
uddufav
DDDDD
DDDDD
favunfavn
unfavfavn
DuDd
DuDd
24
24
Sensitive to d quarkSensitive to u quark
E06-010 Setup• Electron beam: E = 5.9 GeV• 40 cm transversely polarized 3He • BigBite at 30o as electron arm:
Pe = 0.6 ~ 2.5 GeV/c• HRSL at 16o as hadron arm:
Ph = 2.35 GeV/c• Average beam current 12 uA (15
uA in proposal)• Average 3He polarization is ~55%.
(42% in proposal)
e
Polarized3He Target
p
HRSL
16o
g*
e’
BigBite30o
Two large installation Devices: 3He target + BigBite Spectrometer.
Why Polarized 3He Target ?
Effective Polarized Neutron Target!
~90% ~1.5% ~8%
S S’ D
High luminosity: L(n) = 1036 cm-2 s-1 20 mins spin exchange with K/Rb hybrid cells
Pioneer studies performed at KRL
Reached a steady 60% polarization with 15 mA beam and 20 minute spin flip! A NEW RECORD!
Thanks to the hard work of the entire target group!
High Resolution Spectrometer• Left HRS to detect hadrons of
ph = 2.35 GeV/c• Gas Cherenkov + VDC +
Scintillator +Lead-glass detectors
• Aerogel Cherenkov counter– n = 1.015
• RICH detector– n = 1.30
• Kaon detection:– A1: Pion rejection > 90 %– RICH: K/p separation ~ 4 s – TOF: K/p separation ~ 4 s
ep Coincidence Time
s < 400 ps
pK
p
pK
4 σ Separation Cherenkov Ring From RICH
Electron Arm: BigBite
• Wire Chamber Tracking• Shower system and Gas
Cerenkov for electron PID.
Wire chamber
Gas Cerenkov
Shower system
ScintillatorMagnetic field shielding
OpticsSlot-slit
• 64 msr• large out-of-plane
acceptance, essential for separating Collins/Sivers effect
BigBite Optics• Multi-Carbon Target for vertex reconstruction• Sieve Slot for angular reconstruction • Hydrogen elastic scattering at 1.2 GeV and 2.4
GeV for momentum reconstruction• Also positive optics
BigBite Sieve Slit
Contamination (Photon-Induced Electron)• πo induced electrons:
– Direct Decay to γe+e-
– γ interacted with material, pair production
– Same kinematics for e+ and e-
• Single:– Method I: (e+ Data Directly)– Method II: MC
• Coincidence channel:– Ratio method, – Direct from e+ Data
• Consistent with Hall B/C Data
Single
Coincidence
X-bin 1 2 3 4
π+ 21% 8% 2.4% 1.0%
π- 24% 14% 5% 2.0%
Uncer. Rel. 20% 25% 35% 50%
3He Results
After correction of N2 dilution (dedicated reference cell data)Model (fitting) uncertainties are shown in blue band.Other systematic uncertainties shown in red band.
Non-zero Collins moments at highest x bin for π + (2.3 σ stat. + sys. + mod.)
Favor a negative values for Sivers π + results.
Comparison with World Data
Proton Dilution
He
pHen
p
n
pnHe
ppnnHe
f
p
p
pp
3
3
9.04.0
6.32
3
3
2
%8.2
%86
2
2
Effective Polarization ApproachPlane Wave Approximation
fn measured with dedicated data. Corrected by Proton Asymmetries. Nuclear effect ISI under control: S. Scopetta PRD75 054005 (2007)Unpolarized FSI: <3.5% from multiplicity measurementSpin-dependent FSI were estimated to be well below 1% within a simple Glauber rescattering model
nn
ppnHen Pf
APfAA
)1(3
Results on Neutron• Sizable Collins π+
asymmetries at x=0.34?– Sign of violation of
Soffer’s inequality?– Data are limited by stat.
Needs more precise data!
• Negative Sivers π+
Asymmetry– Consistent with
HERMES/COMPASS– Independent
demonstration of negative d quark Sivers function.
Model (fitting) uncertainties shown in blue band.Radiative correction: bin migration + uncer. of asy.Spin-dependent FSI estimated <1% (Glauber rescattering + no correction) Diffractive rho: 3-10%
Best Measurements on Neutron at High x
Paper Appeared on arXiv• arXiv: 1106.0363, will submit in a few days.
Experimental Overview• SoLID (proposed for PVDIS) 3He(e,e’π+/-)– Large acceptance: ~100 msr for polarized (without baffles)– High luminosity
• High pressure polarized 3He target – SIDIS: improve by a factor of 100-1000
• 11 GeV beam,15 µA (unpolarized/polarized)• Unpolarized H/D/3He factorization test & dilution corrections
• Two approved experiments: E10-006 & E11-007– SSA in SIDIS Pion Production on a Transversely/ Longitudinally
Polarized 3He Target at 8.8 and 11 GeV.
• White paper: H. Gao et al. Eur. Phys. J. Plus 126:2 (2011)
• Also SBS Transversity Program focus on high Q2.
SoLID Setup for SIDIS on 3He• Shared device with
PVDIS:– GEM Tracker– Light Gas Cerenkov– Calorimeter
• Shared R&D in– GEM– Light collection in
magnetic field.– Fast DAQ– New Calorimeter
System
Additional devices of MRPC, scintillator plane, heavy gas Cerenkov which provide us the capability in hadron detection.
Projections (1 of 48 bins 0.3<z<0.7)
11)sin( HhA TshCollinsUT
Selected Physics Motivation
• 10% measurement of d quark transversity– Test of Soffers bound at high x
• Search for sign change in Sivers function– Measure Sivers function at high PT
– Data at high x low Q2 for evolution studies– Precision data to test
• First non-zero measurement of Pretzlosity• DSA: Worm-gear functions– Test model calculations > ‐ h1L =? ‐g1T
– Connections with Collinear PDFs through WW approx. and LIR.
YD
qTSIDIS
qT ff
11
Bright Future for TMDs• Golden channel of Electron-
Ion Collider
Dream!
TMDs at EIC• Sea quark TMDs, what will happen at very low x?• Gluon Sivers through back-to-back D-meson production• Twist-3 tri-gluon correlation through D-meson
production• TSSA at medium/large PT Twist-3 approach vs. TMDs• Test Collins-Soper Evolution for high vs. low Q2 at large
x.
• See more discussion in Duke EIC-TMD workshop summary:– M. Anselmino et al. arxiv:1101.4199 EPJ A47,35 2011.
Summary Measuring Transversity and TMDs through SIDIS open a
new window to understand nucleon (spin) structure. First Direct Neutron SSA @ E06-010
Best neutron results in the valence quark region. “Interesting behavior” of d transversity at large x. Independently confirmation of negative d quark
Sivers function.
Transversity and TMDs: from exploration to precision JLab 12 GeV energy upgrade: an ideal tool for this study
A large acceptance SoLID with high luminosity 3He target TMD: sea quark, gluon, evolution studies TMD vs. twist-3
collinear pdf at large PT @ EIC
BigBite Wire Chamber• Three Chambers, 6 planes each, 200 wires
each plane: more than 3000 wires in total.– Connecting/Debuging/Understanding
• Special thanks to Brandon Craver and Seamus Riordan
• Monitor the hit efficiency• Offline calibration: residual σ ~ 180 um– Time Offset Calibration– Drift Time to Drift Distance conversion– Wire Position – Iteration procedure with help of tracking
Understanding BigBite Tracking• Tracking: Pattern match tree search (Ole)• Online: Low luminosity + Event Display– use elastic electron events (high energy deposition
in calorimeter): >85%– Tracking efficiency vs. luminosity
• Offline: – BigBite GEANT3 Simulation (Comgeant) >95%– 1st pass hydrogen
elastic cross section measurement ~95%
Check of BigBite Optics• Different combination of sieve/target• Sieve runs at 5th pass, carbon foils run at 5th pass• 5th pass hydrogen elastic to check the behavior at
high momentum
Data Quality Check• A good data sample is a key for the success of
data analysis– Low level checks on detector responses on different
detectors• E.g. PMT responses of Gas Cerenkov
– Low level checks on trigger rates/DAQ live times• Identified problems as Q1 quenching• Occasions with DAQ problems
– Careful catalog of all the runs• Web-based Run list (PHP-MYSQL)
– More than one month dedicated time in this work.
Fun with Data Taking• Special thanks to our spokespersons for giving
us a lot of freedom in playing with our system.– Understand the timing and trigger circuit ->
Creation of BigBite retiming circuit + firmly establish all the delays
– Understanding the distribution/background -> BigBite Positive polarity run
– During Janurary run: four problems (Gas Cerenkov spectrum, live time, Helicity signals, Left arm EDTP signal) gradually happened -> a loose L1A cable in the left HRS
Rich Physics Topics
• Pion Collins/Sivers SSA Moments• DSA Moments with polarized beam• Results on Kaons/Protons– Observation of anti-proton
• DIS Ay (inclusive, also g2)• Large asymmetries on inclusive hadron.• …