Jin Huang
Los Alamos National Lab
Based on PhD thesis work at MIT and Jefferson Lab Hall A
For JLab Physics Seminar, Apr 6, 2011
Introduction
•The question: nucleon spin structure beyond collinear limit
•New theories: transverse momentum dependent parton distributions
•Experimental tools: semi-inclusive deep in-elastic scattering (SIDIS)
Jefferson Lab E06-010 6-GeV Transversity
•Experimental setup
•Data analysis
•Results
Future measurements
•Next generation experiment at 12 GeV era, especially using SoLID
•Drell-Yen process, EIC
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
2


Majority mass of visible matter is from
nucleons (proton/neutron)
Knowledge of parton constituent’s
behavior inside nucleon summarized in
Parton Distribution Functions (PDF)
◦ Unpolarized PDF,
mapped 5 orders in x range and Q2
◦ Longitudinally polarized PDF,
mapped 3 orders in x and 2 in Q2

Orbital momentum play important role
in spin structure
◦ Rarely known experimentally, need go multi-D
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
3

TMD PDFs link
◦ Intrinsic motion of partons
◦ Parton spin
◦ Spin of the nucleon

Multi-Dimension structure
◦ Imaging the 3D motion of the quark
◦ Probes orbital motion of quarks

A new phase of study, fast developing field
◦ Great advance in theories (factorization, models, Lattice ...)
◦ Experimentally, not systematically studied until recent years
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
4
FNAL
BNL
JPARC
EIC
lepton
lepton
proton
lepton
pion
proton
antilepton
proton
SIDIS
Partonic scattering amplitude
Drell-Yan, Jets…
electron
pion
positron
pion
Fragmentation amplitude
Distribution amplitude
e–e+ to hadrons
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
5
Simplified
relations
between
distributions
“Parent” Wigner
distributions
Wpq(x,k,r)
2
d
 r
2
 d k (FT)
GPDs
Hpu(x,x,t),
Epu(x,x,t),…
 dx
Form Factors
GE ,GM,...
Measure momentum
transfer to nucleon.
Probability to find a quark q
in a nucleon P with a
certain polarization in a
position r and momentum k
TMDs
h1T(x,k) , ...
2
d
 k
x=0,t=0
PDFs
Ex. f(x),
g1(x), ...
Measure momentum
transfer to quark.
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
6
Nucleon Spin
Quark Spin
Quark polarization
Unpolarized
(U)
Nucleon Polarization
U
Longitudinally
Polarized (L)
Transversely
Polarized (T)
h1 =
f1 =
Boer-Mulders
h1L =
g1 =
L
Worm Gear
(Kotzinian-Mulders)
Helicity
h1 =
T
f 1T =
Sivers
g1T =
Worm Gear
(trans-helicity)
Transversity
h1T =
Pretzelosity
: Survive trans. momentum integration
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
7
Nucleon Spin
Quark Spin
Quark polarization
Unpolarized
(U)
Nucleon Polarization
U
Longitudinally
Polarized (L)
Transversely
Polarized (T)
h1 =
f1 =
Boer-Mulders
h1L =
g1 =
L
Worm Gear
(long-transversity)
Helicity
h1 =
T
f 1T =
Sivers
g1T =
Worm Gear
(trans-helicity)
Transversity
h1T =
Pretzelosity
: Also accessed in E06-010
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
8
Nucleon Spin
Quark Spin
Quark polarization
Unpolarized
(U)
Nucleon Polarization
U
Longitudinally
Polarized (L)
Transversely
Polarized (T)
h1 =
f1 =
Boer-Mulders
h1L =
g1 =
L
Worm Gear
(long-transversity)
Helicity
h1 =
T
f 1T =
Sivers
g1T =
Worm Gear
(trans-helicity)
Transversity
h1T =
Pretzelosity
: This talk
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
9



g1T =
Leading twist TMD PDFs
T-even, Chiral-even
Dominated by real part of
interference between
L=0 (S) and L=1 (P) states
Worm Gear
g1T (1)
S-P int.
◦ Imaginary part ->
Sivers effect

TOT
No GPD correspondence
P-D
int.
◦ a genuine sign of intrinsic
transverse motion

Poorly known experimentally
Light-Cone CQM by B. Pasquini
B.P., Cazzaniga, Boffi, PRD78, 2008
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
10


So far using simplified straight gauge links
“Worm-gear” TMDs → dipole shift @ Trans Mom.
B. Musch, et. al. arXiv:0908.1283; 1011.1213, mπ~500GeV
u
d
u
d
Spin: Nucleon (T), Quark (L)
Spin: Nucleon (L), Quark (T)
-
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
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
Active theoretical studies, including modeling
Generic features of model predictions:
arXiv:0806.2298 [hep-ph]

Models (early stage):

◦ max @ valence x region
◦ ~ a few percent w.r.t. unpolarized f1
◦ h1Lq and g1T q take opposite signs
◦ WW-type calculation (shown right)

◦
◦
◦
◦
◦
Diquark spectator models
Constituent Quark Model (LCCQM)
Covariant Parton Model
Quark-Diquark Model
Bag Model
Jin Huang <jinhuang@lanl.gov>
LCCQM
WW-type
JLab Physics Seminar
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


Gold mine for TMDs
Access all eight leading-twist
TMDs through spin-comb. &
azimuthal-modulations
Tagging quark
flavor/kinematics
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
13
d
2
y2


2
2
dxdydS dzdh dPh  xyQ 2(1   )
f1 =
{FUU ,T 
cos(2h )
  cos( 2h )  FUU
 ...
Boer-Mulder
h 1 =
Worm Gear
g1T =
Helicity
g1 =
Worm Gear
h1L =
sin(2h )
 S L [ sin( 2h )  FUL
 ...]
Transversity
h1T =
sin(h  S )
 ST [ sin( h  S )  FUT
Sivers
f 1T =
sin(h  S )
 sin( h  S )  ( FUT
 ...)
h1T =
sin(3h  S )
  sin( 3h  S )  FUT
 ...]}
Pretzelosity
 ST e [ 1   2 cos(h  S )  FLTcos(h S )  ...]
 S L e [ 1   2  FLL  ...]
SL, ST: Target Polarization; e: Beam Polarization
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
14

Double Beam-Target Spin Asymmetry (DSA) in SIDIS
with transversely polarized target: ALT
cos(h  s )
LT
A


d d  d  cos(  

2




d

d


d


h
s
h
s
)
h
s
 g1qT  D1hq
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
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
Models predict few to 20 percent asymmetry for
◦ Neutron ALT at Jlab kinematics
g1 Data + WW relation
Diquark Spectator Model
A. Kotzinian, etc., PRD 73 114017 (2006)
arXiv:1003.1328v1
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
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

No measurement until 2002
Preliminary COMPASS results
Proton
arXiv:1012.0155 [hep-ex]
◦ ALT on proton and deuteron
◦ Fixed beam helicity (μ beam)

◦ Low x, small predicted asymmetry
Preliminary HERMES results
◦ ALT on proton
◦ Reported in Apr. 2011

New measurement needed
◦ Different target for flavor decomposition
◦ Higher precision at valence region
Preliminary
arXiv:1107.4227 [hep-ex]
•
•
First neutron ALT measurement
Flagship experiment using
polarized 3He target at JLab
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
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

Newport News, Virginia
Linear accelerator provides
continuous polarized
electron beam
◦ Ebeam = 6 GeV
◦ Pbeam = 85%


3 experimental halls
E06-010 in Hall A
A
Jin Huang <jinhuang@lanl.gov>
B
C
JLab Physics Seminar
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Institutions (38)
Univ. Kentucky, W&M, Duke Univ., CalTech, UIUC, Lanzhou Univ, California State Univ, Univ.
Glasgow, MIT, CMU, JLab, ODU, UVa, Hampton Univ, INFN, Mississippi State Univ, Rutgers, Kharkov
Inst. of Phys. and Tech., Los Alamos National Lab, Longwood Univ, Cairo Univ, Kyungpook National
Univ, China Inst. of Atomic Energy, Kent State Univ, Univ. of Sci. & Tech. of China, Florida
International Univ., Univ. Massachusettes, Temple Univ, Univ. Blaise Pascal, Univ. of New Hampshire,
Syracuse Univ., Yerevan Physics Inst., Univ. Ljubljana, Seoul National Univ.
Collaboration members (115)
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, W. Chen, K. Chirapatpimol,
E. Chudakov, E. Cisbani, J. C. Cornejo, F. Cusanno, M. M. Dalton, W. Deconinck, C.W. de Jager,
R. De Leo, X. Deng, A. Deur, H. Ding, P. A. M. Dolph, C. Dutta, D. Dutta, L. El Fassi, S. Frullani ,
J. Huang, H. Gao, F. Garibaldi, D. Gaskell, S. Gilad, R. Gilman, O. Glamazdin, S. Golge, L. Guo,
D. Hamilton, O. Hansen, D.W. Higinbotham, T. Holmstrom, M. Huang, H. F. Ibrahim, M. Iodice,
X. Jiang, G. Jin, M. K. Jones , J. Katich, A. Kelleher, W. Kim, 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, S. K. Phillips, M. Posik,
A. J. R. Puckett , X. Qian, Y. Qiang, A. Rakhman, R. D. Ransome, S. Riordan, A. Saha, B. Sawatzky,
E. Schulte, A. Shahinyan, M. H. 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, and X. Zong
Co-spokesperson , Graduate student, Leading Postdoc
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
20

Successful data taking 2008-09

Polarized electron beam
Luminosity
Monitor
◦ With 30 Hz helicity reversal

Polarized 3He target

BigBite at 30º detect electron
◦ Dipole magnet, Pe = 0.6 ~ 2.2 GeV/c
◦ MWDC/shower-preshow/scitillator

HRSL at 16º detect hadron
◦ QQDQ config, Ph = 2.35 GeV/c
◦ Scintillator/drift chamber/Cherenkov
Jin Huang <jinhuang@lanl.gov>
Beam Polarimetry
(Møller + Compton)
JLab Physics Seminar
21
Experiment Setup
Only Small Part of Left-HRS and He-3 Target is Shown
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
22
Luminosity
Monitor
Beam
Polarimetry



Overall polarization
<P>=76.8 +- 3.5%
Fast beam helicity
reversal at 30 Hz
Beam charge balance
between two helicity
states



Polarized beam at
Jefferson Lab is crucial
Standard Hall A Polarimetry
Polarized e-+e-e-+ePerformed per week (invasive)
Møller Polarimeter
http://www.jlab.org/~moller/E06-010.html
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
23
Luminosity
Monitor

Beam
Polarimetry
~90%


~1.5% ~8%
High Luminosity polarize target
Compact size: No cryogenic support needed
Beam
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
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Luminosity
Monitor

New laser
◦ Narrow line width
◦ 3He ↑P/P ~30%

Beam
Polarimetry
New optics and oven
◦ Polarizing and
polarimetery
at 3 directions

Holding magnet field
◦ 3D field hold spin to
any direction

A smart target
◦ Flip 3He spin every 20min
◦ <10-3 failure rate
◦ Auto analysis, log
and early warnings
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
25
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
26
Luminosity
Monitor



High luminosity: L(n) = 1036 cm-2 s-1
Record high 50-65% polarization in beam with automatic spin
flip / 20min
<P> = 55.4% ± 0.4% (stat. per spin state) ± 2.7 % (sys.)
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
Beam
Polarimetry
27
Luminosity
Monitor


HRSL to detect hadrons of ph =
2.35 GeV
QQDQ magnet configuration
Beam
Polarimetry
Detector
Package
◦ Very high momentum resolution

Detector Hut
Drift chambers
◦ Tracking

Scintillator planes
◦ Trigger & Timing, pi/p separation

Gas Cherenkov & lead-glass
shower detectors
◦ e/hadron separation

Aerogel Cherenkov & RICH
◦ π/K separation
Q1
Q2
D1
Jin Huang <jinhuang@lanl.gov>
Q3
JLab Physics Seminar
28
Luminosity
Monitor

Detector
◦ Clean e/π separation with
Gas Cherenkov counter and Leadglass detector


Spectrometer optics

Beam
Polarimetry
3D momentum and vertex
reconstructions
Electron contamination in pions <10-4
◦ Kaon rejection in pion by:
Aerogel Cerenkov with kaon rejection 10:1
 Kaon contamination in pion <0.6%
Beam
HRS
Entrance
◦ Scintillator: timing σ~150ps
e’
Sieve Plate
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
Vertex
29
Luminosity
Monitor



Detects electrons
Single dipole magnet
A “big bite” of acceptance
Beam
Polarimetry
◦ DW  64 msr
◦ P : 0.6 ~ 2.2 GeV/c




3 wire chambers: 18 planes
for precise tracking
Bipolar momentum
reconstruction
Pre-shower and shower for
electron PID
Scintillator for coincidence
with left HRS
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
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
Optics for both negative and positive
charged particles
◦
◦
◦
◦

Chamber resolution: 180um
Angular resolution: < 10 mrad
Momentum resolution: 1%
Vertex resolution: 1 cm
e-pi separation with
calorimeters (shower-preshower)
◦ Pion contamination in SIDIS electron <2%
BigBite Sieve Slit
Electron-pion separation
Jin Huang <jinhuang@lanl.gov>
Invariant mass of p(e,e’)
JLab Physics Seminar
31
Luminosity
Monitor

Beam
Polarimetry
Time-of-Flight
◦ Detector: Scintillator planes in both
spectrometers
◦ Coincidence timing-of-flight
resolution ~ 340ps
◦ proton/π separation @ 2.4GeV

Vertex
◦ Coincidence resolution ~ 1cm
(Visible Target Length ~ 30cm)

Random background <1%
δA≤ 0.3×10-3 (very minor)
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
32
x bin 1 2
3
4
Q2>1GeV2
W>2.3GeV
z=0.4~0.6
W’>1.6GeV
Kinematics coverage
pT & ϕh- ϕS coverage
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
33

Frequent beam-target double spin reversals
◦ Cancels single spin related structure function and final
state interactions
◦ Cancel sys. uncert. due to acceptance, yield drift, lumi.

Two analysis team
◦ Independent analysis after detector calibration
◦ Blue Team
 A local pair-angular bin-fit method
◦ Red Team
 Developed maximum likelihood estimator
◦ Result from both team agree well
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
34




Target spin perpendicular to initial electron momentum
Small longitudinal target spin parallel to virtual photon
-> ALL asymmetry related to helicity PDF
~7o
*
Correction ~ SL * ALL
 Estimated using maximum likelihood
Estimation of ALL
1.
Global analysis -> A1(3He->pi)
g






Trans. momentum dependence
Long./trans. cross section ratio
Kinematic factor
BigBite
h+/-
A1 is trans. momentum integrated ALL
Calculated by Dr. R. Sassort (DSSV 2008)
A1 -> ALL by taking account of
2.
30o
3He
e’
Spin
Other corrections:
SL
ST
PT
e
nitrogen/charge sym. background correction
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
35



First published ALT data
Data suggest non-zero SIDIS ALT: π-, +2.8σ (sum all bins)
First indication of non-zero g1T
therefore non-zero quark OAM interferences
Huang, et. al. PRL. 108, 052001 (2012)
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
36

~90%
~1.5% ~8%

n
q
h
A

g

D
1q , sensitive to d quark
◦ LT 1T
◦ Dominated by L=0 (S) and L=1 (P) interference

Corrected for proton dilution (unpolarized part)
◦ Measured with dedicated data of unpolarized hydrogen, He-3

Proton asymmetry contribution
◦ Based on the COMPASS preliminary results
◦ Crosschecked with the recent HERMES preliminary results
◦ δA/Δstat.A ≤12%
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
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Huang, et. al. PRL. 108, 052001 (2012)


Consistent with models in signs
Suggest larger asymmetry, possible interpretations:
◦ Larger quark spin-orbital interference
◦ different PT dependence
◦ larger subleading-twist effects
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
38


≈
-2σ Negative asymmetry observed:
Suggest
Negative
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
39
g1Tu
>?0
d quark in
arXiv:1108.0489
neutron
dominant
ALT(n→π-)
⊥u
h1L <?0
u in proton
dominant
ALT(n→π-)
π+
E06-010 ALT on 3He
CLAS AUL on proton
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
40
Phys. Rev. Lett. 107, 072003 (2011)
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
41
E12-11-007 & E12-11-006
Fully approved for 12GeV
New SoLID spectrometer
High lumi. pol. 3He target
Super BigBite
CLAS polarized SIDIS program
Drell-Yen process in pp, EIC
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
42





Key device to achieve high-precision mapping and minimizing systematics
High Luminosity target and upgraded beam energy -> 12 GeV
Large acceptance: enable 4D-mapping
Full/symmetric azimuthal angular coverage: small systematics
Device shared by three SIDIS experiment and a parity-violation DIS exp.
 Budget: ~20M; early design stage; detector prototyping
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
43

e’ π±)X, continuation and next-generation of 6-GeV measurement
◦ E12-11-007 & E12-11-006 using SoLID, max precision, “A”-rated
◦ E12-09-108 using Super-BigBite, also cover Kaons
p(e, e’ π±)X, PR12-11-108 conditionally approved, proton target
JLab will lead the world measurement on ALT and knowledge on g1T function
E12-11-007 projection neutron ALT of one out of 48 Q2-z bins for π-
Scale for error bars:

3He(e,
Center of points:

Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
44
E12-11-007 Full projection, neutron ALT
Satisfying the multi-D natural of this study
Ph⊥ (GeV/c)
Q2 = 1~8 GeV2
z= 0.3~0.7
xbj
data point: Projection for neutron ALT of π-
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
45

g1T can be probed in Drell-Yen process
◦ Azimuthal weighted double spin asymmetry in
transverse polarized p – p(p_bar) -> g1T
Azimuthal
Weights

Lu, et.al. PhysRevD.75.094012
EIC: g1T for sea quarks
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
46

First measurement of 3He (neutron) ALT
◦ First indication of non-zero ALT (+2.8 σ π+ production on 3He)
◦ Suggest non-zero g1T and Re[(L=0)q × (L=1)q]
◦ Huang, et. al. PRL. 108, 052001 (2012), arXiv:1108.0489

Systematic uncertainties is minimized by
unique fast beam helicity/target spin flip
◦ Cancel systematic effect due to
efficiency drift/acceptance/luminosity fluctuation/SSA terms

Foundation for future experiments
◦ Precise mapping of ALT following JLab 12 GeV upgrade
◦ Comprehensive study of spin-orbital correlations
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
47
Jin Huang
<jinhuang@lanl.gov>
JLab Physics Seminar
Cake-print for End of run party,
designed
by Dr. Y. Qiang
48
Jin Huang <jinhuang@lanl.gov>
JLab Physics Seminar
49