Yi Qiang
Duke University
for the Workshop on Hadron Physics in China
and Opportunities with 12 GeV JLab
July 31, 2009
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Yi Qiang <yqiang@jlab.org>
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Outline
 Overview of leading twist TMDs
 Jefferson Lab Experiment E06-010
 First neutron Transversity experiment
 Experimental configuration
 Polarized 3He target
 Detector performance
 Future plan and impact
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Nucleon Structure from DIS
 Un-polarized Nucleon Structure Function f1 =
 Longitudinal Momentum Distribution
 Well probed for 50 years over very large kinematics
range
 Longitudinal Polarized Nucleon Structure Functions
 Since “spin crisis” in 1980s
g1 =
 Plotted in fairly large range
h1 =
 Transversity:
 Can be probed in Semi-Inclusive DIS
 New business: recent measurements from HERMES and
COMPASS using Hydrogen and Deuteron targets
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Leading Twist TMDs
Quark polarization
Nucleon Polarization
Un-Polarized
U
Longitudinally
Polarized
h1  =
f1 =
g1 =
L
Transversely
Polarized
h1L =
h1 =
T f =
1T
g1T =
h1T =
Blue: kT independent; Red: T-odd
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Access Leading Twist Parton Distributions
through Semi-Inclusive DIS
d
2
y2


2
2
dxdydS dzdh dPh  xyQ 2(1   )
{FUU ,T  ...
cos(2h )
UU
  cos( 2h )  F
Boer-Mulder
Unpolarized
 ...
sin(2 h )
 S L [ sin( 2h )  FUL
 ...]
sin(h  S )
 ST [ sin( h  S )  FUT
Transversity
Polarized
Target
sin(h  S )
 sin( h  S )  ( FUL
 ...)
Sivers
sin(3 h  S )
  sin( 3h  S )  FUT
 ...]
Pretzelosity
 S L e [ 1   2  FLL  ...]
Polarized
Beam and
cos(h  S )
2
 ST e [ 1   cos(h  S )  FLT
 ...]} Target
SL, ST: Target Polarization; e: Beam Polarization
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Transversity from JLab Hall A
 Linear accelerator
provides continuous
polarized electron beam
 Ebeam = 6 GeV
 Pbeam = 85%
 3 experimental halls
A
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B
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C
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E06-010 Collaboration
 E06-010: Single Target-Spin Asymmetry in Semi-Inclusive
n↑(e, e’p±) Reaction on a Transversely Polarized 3He Target
 Spokespersons:
Xiaodong Jiang (Rutgers/Los Alamos, Contact Person), Jian-ping
Chen (JLab), Evaristo Cisbani (INFN-Rome), Haiyan Gao (Duke),
Jen-Chieh Peng (UIUC)
 Thesis Students:
C. Dutta (Kentucky), J. Huang (MIT), A. Kalyan (Kentucky), J.
Katich (W&M), X. Qian (Duke), Y. Wang (UIUC), Y. Zhang
(Lanzhou U)
 Approved with A rating and was just finished in early
February, 2009.
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E06-010 Setup
• Electron beam: E = 5.9 GeV
• 40 cm polarized 3He target
16o
g*
• BigBite at 30 degrees as
BigBite
30o
HRSL
p
Polarized
3He Target
e
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e’
electron arm:
P = 0.7 ~ 1.8 GeV/c
• HRSL at 16 degrees as
hadron arm:
P0 = 2.35 GeV/c
• Measure Collins, Sivers and
pretzelosity asymmetries in
valence range:
x = 0.1 ~ 0.4
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Separation of Collins, Sivers and Pretzelosity
effects through angular dependence


1
N

N
AUT (hl , Sl ) 
P N  N
Vertical
Horizontal
 Rotate target spin direction
to increase s coverage
 UT  ST (1  y )
Ph 
sin( hl  Sl )   eq2 h1q ( x) H1qh ( z , Ph2 )
zM h
y 2 Ph 
 ST (1  y  )
sin( hl  Sl )   eq2 f1T q ( x) D1hq ( z h , Ph2 )
2 zM N
Transversity
Sivers
Ph3
 ST (1  y ) 2 2
sin( 3hl  Sl )   eq2 h1Tq ( x) H1qh ( z h , Ph2 ) Pretzelosity
6z M N M h
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Polarized
3He
Target
 Effective polarized neutron target
 High luminosity: L(n) = 1036 cm-2 s-1
~90%
~8%
~1.5%
 Fast spin exchange with K/Rb hybrid cells
Laser
795 nm
Oven
230 oC
Pumping
Chamber
F = 3”
25 G Holding Field
Target Chamber
40 cm
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Target Setup for Transversity
 New vertical coil together with
existing horizontal coils and new
oven allow 3He to be polarized in
ALL three directions!
 New narrow band
COMET lasers make
optical pumping more
efficient.
 3He spin pumped to
horizontal and vertical
directions.
 Auto spin flip every 20
minutes.
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3He
Target Polarimetries
 NMR: Nuclear Magnetic Resonance
 Free NMR at pumping chamber
from every auto spin flip.
 Target chamber polarization is
calibrated by Water NMR
measurement.
Water
NMR
 EPR: Electron Paramagnetic
Resonance
EPR
 Got signal from both K and Rb.
 Measures pumping chamber
polarization.
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Target Performance
 Online preliminary EPR/NMR
analysis shows a stable 65%
polarization with 15 mA beam
and 20 minute spin flip
Cell: Astral
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Cell: Maureen
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BigBite Spectrometer
 30 degrees to the beam right
 Detect electrons
 A big bite of acceptance
 DW  64 msr
 P : 700 ~ 1800 MeV/c
 3 Wire Chambers: 18 planes
 Optics is crucial for the angular
dependence separation and
kinematics variables
 Pre-Shower and Shower for
electron PID
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BigBite Optics
 Optics for both negative and positive charged




particles have been done
Wire Chamber Spatial Resolution: 180 mm
Vertex Resolution: 1 cm
Angular Resolution: < 10 mrad
Momentum Resolution: 1%
BigBite Sieve Slit
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Electron Selection in BigBite
 Pre-shower/Shower have been calibrated
 Energy Resolution: 8%
 Well separated electrons and pions
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Left High Resolution Spectrometer
 16 degrees to beam left with
p0 = 2.35 GeV/c
 Clean e/p separation with Gas
Cherenkov and Pion Rejector
 Vertex and TOF coincidence
with BigBite will help reduce
the background
 Kaon asymmetry data can also
be extracted:
 < 400 ps
p
p
K
K p
ep Coincidence Time
 A1: Pion rejection > 90 %
 RICH: K/p separation ~ 4 
 TOF: K/p separation ~ 4 
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4  Separation
Neutron Transversity in Jefferson Lab Hall A
Cherenkov Ring
from RICH
Yi Qiang <yqiang@jlab.org>
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Kinematics Coverage
y
0.6 ~ 0.9
0.6 ~ 3
x<0.25
(GeV/c)2
Q2
Sivers Angle:
hh-3+
shs-s
Collins
Angle:
Pretzelosity
Angle:
W’
1.5 ~ 2.3 (GeV/c2)
x>0.25
0.4 ~ 0.6
z
0
0.25 x
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0.5
Neutron Transversity in Jefferson Lab Hall A
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Projections of Collins and Sivers Functions
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Projections of g1T
 First Neutron (3He) Measurement
 With Fast Beam Helicity Flip (30Hz)
 Projected Uncertainties (Stat. Only):
 2.3% at low x
 3.4% at high x
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Status of E06-010
 The experiment was smoothly performed
from Oct 2008 to Feb 2009.
 Statistics exceeded the approved goal.
 Detector calibrations and target analysis are
ongoing.
 Will start to extract physical asymmetries
afterwards.
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Future Plan and Impact
 Finish all the data quality check, detector calibration and





target analysis by Sep 2009.
Extract raw asymmetries: witness channel, blind analysis
and then raw physics asymmetry by Nov 2009.
Apply other corrections: dilution factor, background
asymmetry correction, radiative correction and etc.
Final asymmetries separation: Collins, Sivers …
The results from this experiment will provide important
constraints on the TMDs of u, d and s quarks in the valence
quark region when combined with world data.
The experience obtained will greatly help us to plan the
future SIDIS experiments.
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E06-010 Collaboration
 Institutions
California State Univ., Duke Univ., Florida International. Univ., Univ. Illinois, JLab, Univ. Kentucky,
LANL, Univ. Maryland, Univ. Massachusetts, MIT, Old Dominion Univ., Rutgers Univ., Temple Univ.,
Penn State Univ., Univ. Virginia, College of William & Mary, Univ. Sciences & Tech, China Inst. Of
Atomic Energy, Beijing Univ., Seoul National Univ., Univ. Glasgow, INFN Roma and Univ. Bari, Univ.
of Ljubljana, St. Mary’s Univ., Tel Aviv Univ.
 Collaboration members
A.Afanasev, K. Allada, J. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, F. Butaru, G. Cates, C.
Chang, J.-P. Chen (Co-SP), W. Chen, S. Choi, C. Chudakov, E. Cisbani(Co-SP), E. Cusanno, R. De
Leo, A. Deur, C. Dutta, D. Dutta, R. Feuerbach, S. Frullani, L. Gamberg, H. Gao(Co-SP), F. Garibaldi,
S. Gilad, R. Gilman, C. Glashausser, J. Gomez, M. Grosse-Perdekamp, D. Higinbotham, T. Holmstrom,
D. Howell, J. Huang, M. Iodice, D. Ireland, J. Jansen, C. de Jager, X. Jiang (Co-SP), Y. Jiang, M. Jones,
R. Kaiser, A. Kalyan, A. Kelleher, J. Kellie, J. Kelly, A. Kolarkar, W. Korsch, K. Kramer, E. Kuchina, G.
Kumbartzki, L. Lagamba, J. LeRose, R. Lindgren, K. Livingston, N. Liyanage, H. Lu, B. Ma, M.
Magliozzi, N. Makins, P. Markowitz, Y. Mao, S. Marrone, W. Melnitchouk, Z.-E. Meziani, R. Michaels,
P. Monaghan, S. Nanda, E. Nappi, A. Nathan, V. Nelyubin, B. Norum, K. Paschke, J. C. Peng(Co-SP),
E. Piasetzky, M. Potokar, D. Protopopescu, X. Qian, Y. Qiang, B. Reitz, R. Ransome, G. Rosner, A.
Saha, A. Sarty, B. Sawatzky, E. Schulte, S. Sirca, K. Slifer, P. Solvignon, V. Sulkosky, P. Ulmer, G.
Urciuoli, K. Wang, Y. Wang, D. Watts, L. Weinstein, B. Wojtsekhowski, H. Yao, H. Ye, Q. Ye, Y. Ye, J.
Yuan, X. Zhan, Y. Zhang, X. Zheng, S. Zhou.
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Fermi Lab E704: p↑p→pX at 400 GeV
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