Transcript Jefferson Lab E06-010 Collaboration Institutions CMU, Cal-State LA, Duke, Florida International, Hampton, UIUC, JLab, Kharkov, Kentucky, Kent State, Kyungpook National South Korea, LANL,

Jefferson Lab E06-010 Collaboration
Institutions
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
f1u(x,kT)
Nucleon
Spin
3-D
Tomogr
aphy
Models
TMD
QCD
Dynam
ics
Lattice
QCD
QCD
Factoriz
ation
Quark
OAM/
Spin
Leading-Twist TMD PDFs
Nucleon Spin
Quark Spin
Quark polarization
Unpolarized
(U)
Nucleon Polarization
U
Longitudinally Polarized
(L)
Transversely Polarized
(T)
h1 =
f1 =
Boer-Mulders
h1L =
g1 =
L
Helicity
Worm Gear
(Kotzinian-Mulders)
h1 =
T
f 1T =
Transversity
g1T =
Sivers
h1T =
Worm Gear
Pretzelosity
: Survive trans. momentum integration
Separation of Collins, Sivers and pretzelocity effects through angular dependence


1
N

N
AUT (hl ,  Sl ) 
P N  N
Collins
Sivers
 AUT
sin(h  S )  AUT
sin(h  S )
ty
 AUPretzelosi
sin(3h  S )
T
Collins
AUT
 sin(h  S )
Sivers
AUT
 sin(h  S )
UT
UT
 h1  H1
 f1T  D1
AUPretzelosity
 sin(3h  S )
T
UT
 h1T  H1
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?
N
J. P. Ralston arxiv:0810.0871


q
q
Chiral-odd → difficult to access in inclusive DIS
Tensor Charge: Integration of transversity over x.
 Calculable in LQCD
Helicity
state
N
Parton Distributions
(CTEQ6)
(Torino)
Unpolarized
Helicity
Transversity
Rich Physics in TMDs (Sivers Function)
• Correlation between nucleon spin with quark orbital
angular momentum
Sivers

A
 f1T  D1
Burkhardt :
chromodynamic
lensing
f1Tq
SIDIS
  f1Tq
D Y
Important test for
Factorization
Final-State-Interaction
Experiments on polarized ``neutron’’ urgently needed!!
4
4
1
8
1
P  up ( )  up( )  d p ( )  up ( )  d p ( )
9
9
9
9
9
4
1
1 C .S .
4
2
N  un ( )  d n ( )  d n ( )  d p ( )  u p ( )
9
9
9
9
9
D fav  Du   Dd   Dd   Du 
Dunfav  Dd   Du   Du   Dd 
 (ud )

 (ud )

 n   4d  D fav  2u  Dunfav
 n   4d  Dunfav  2u  D fav
Sensitive to d quark
Sensitive to u quark
u quark dominated
Sensitive to d quark
E06-010 Setup
16o
g*
BigBite
30o
HRSL

Polarized
3He Target
e
e’
• 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)
Two large installation Devices:
3He target + BigBite Spectrometer.
Why Polarized 3He Target ?
S
S’
D
Effective Polarized
Neutron Target!
~90%
~1.5%
High luminosity: L(n) = 1036 cm-2 s-1
~8%
Pioneer studies performed at KRL
20 mins spin exchange with K/Rb hybrid cells
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
 < 400 ps
p

K
K 
e Coincidence Time
• RICH detector
– n = 1.30
• Kaon detection:
– A1: Pion rejection > 90 %
– RICH: K/ separation ~ 4 
– TOF: K/ separation ~ 4 
4 σ Separation
Cherenkov Ring
From RICH
Electron Arm: BigBite
Shower system
Scintillator
Gas Cerenkov
Wire chamber
Optics
Slot-slit
Magnetic field
shielding
• 64 msr
• large out-of-plane
acceptance, essential for
separating Collins/Sivers
effect
• Wire Chamber Tracking
• Shower system and Gas
Cerenkov for electron
PID.
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
• Single:
– Method I: (e+ Data Directly)
– Method II: MC
• Coincidence channel:
– Ratio method,
– Direct from e+ Data
Coincidence
• Consistent with Hall B/C Data
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
Non-zero Collins
moments at
highest x bin for
π + (2.3 σ stat. +
sys. + mod.)
Favor a negative
values for Sivers
π + 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.
Comparison with World Data
Proton Dilution

Effective Polarization Approach
Plane Wave Approximation
An 
A3He  (1  f n ) Pp Ap
f n Pn


 3 He  pn  n  2 p p  p
 3 He   n  2 p
pn  8632.6 %
p p  2.800..49 %
 3 He  2 p
fn 
 3 He
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 measurement
Spin-dependent FSI were estimated to be well below 1%
within a simple Glauber rescattering model
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
Model (fitting) uncertainties shown in blue band.
demonstration of
negative d quark Sivers Radiative correction: bin migration + uncer. of asy.
Spin-dependent FSI estimated <1% (Glauber rescattering +
function.
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)
Collins
AUT
 sin(h  s )  h1T  H1
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
q
q
f


f
– Precision data to test 1T SIDIS
1T D Y
• First non-zero measurement of Pretzlosity
• DSA: Worm-gear functions
– Test model calculations ‐> h1L =? ‐g1T
– Connections with Collinear PDFs through WW
approx. and LIR.
Bright Future for TMDs
• Golden channel of ElectronIon 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
3
 A large acceptance SoLID with high luminosity He 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.
• …