E06-010 / E06-011 Transversity Experiments Overview, Manpower and Safety

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E06-010 / E06-011 Transversity
Experiments Overview, Manpower and Safety
Readiness Review, March 19, 2007
Spokesperson Jian-Ping Chen, Evaristo Cisbani,
Haiyan Gao, Xiaodong Jiang, Jen-Chieh Peng

• Goal of the transversity experiments
• Requirements of the transversity experiments
• Collaboration and manpower
• Safety issues

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Physics Motivation Transversity

• Remaining frontier of kT independent structure
  functions
• Connections to many other kT dependent
  distribution and fragmentation functions
• Major experimental efforts to measure
  transversity using lepton and hadron beams

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How to measure transversity?

• Chiral-odd ? not accessible in DIS
• Require another chiral-odd object

• Transversely Polarized Drell-Yan
• Semi-Inclusive DIS
• Single-hadron (Collins fragmentation function,
  H1-(z))
• Two hadrons (Interference fragmentation function)
• Vector meson polarization
• ? - polarization

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Leading-Twist Quark Distributions
Semi-inclusive DIS

can access all leading-twist quark distributions

( A total of eight distributions)

Three have no kT dependence
Transversity

The other five are transverse momentum (kT)
dependent (TMD)
Sivers function
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Observation of Single-Spin Azimuthal Asymmetry
ep ? epx
HERMES
Longitudinally polarized target
ltSTgt 0.15
Origins of the sin(?) azimuthal asymmetry ?
Collins effect Correlation between the quarks
transverse spin with pions pT in the
fragmentation process ? dq(x) H1 - (z). Sivers
effect Correlation between the transverse spin
of the proton with the quarks transverse
momentum ? f1T- (x) D(z). Other higher twist
effects could also contribute.
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Use transversely polarized hydrogen target to
separate the two effects (Collins vs. Sivers)
Simultaneous fit to sin(? ?s) and sin(? - ?s)
(?s is the azimuthal angle of the target spin)
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Extraction of Collins functions from the Collins
asymmetry measurements
Fits to the Hermes data
Prediction of the Compass data
( Vogelsang and Yuan, hep-ph/0507266 )
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Extraction of Sivers functions from the Sivers
moment measurements
Fits to the Hermes data
Prediction of the Compass data
( Vogelsang and Yuan, hep-ph/0507266 )
Striking flavor dependence of the Sivers function
(Sd -2Su)
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Opportunities at JLab for transversity experiments

• High-intensity CW electron beam
• High-density polarized 3He target which could be
  polarized transversely
• Probe valence-quark region similar to HERMES
  kinematics, providing complimentary information
  on transversely polarized neutron
• An independent test of the striking flavor
  structures of Collins and Sivers functions
  observed at HERMES/COMPASS

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3He?(e,ep,-)x at Hall-A

• Beam
• 6 GeV, 15 µA e- beam
• Target
• Optically pumped Rb-K spin-exchange 3He target,
  50 mg/cm2, 42 polarization, transversely
  polarized with tunable direction
• Electron detection
• BigBite spectrometer, Solid angle 60 msr, ?Lab
  300
• Charged pion detection
• HRS spectrometer, ?Lab -160

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Kinematic coverage of the electron arm

• BigBite spectrometer set at ?30 at beam-right
  detecting electrons with 0.5 lt E lt 2.2 GeV.
• The coverage in Bjorken-x is 0.135 lt x lt
  0.405, corresponding to valence-quark region.
• For the four x bins, the range of mean-Q2 is 1.3
  lt ltQ2gt lt 3.1 (GeV/c)2.
• The coverage in W, the invariant mass of the
  hadronic system, is 2.33 lt W lt 3.05 GeV, well
  above the resonances region.

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Hall-A polarized 3He target

• 40-cm long Rb-K spin-exchange hybrid cell at 10
  atm with beam current of 15 µA
• 42 target polarization with spin-flip frequency
  of 20 minutes
• A third set of Helmholtz coils will be added,
  together with the laser optics, to allow for
  vertical polarization of the 3He target

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Kinematic coverage of the hadron arm

• HRSL situated at ? -16 will measure charged
  hadrons with mean momentum p 2.4 GeV/c.
• The fraction of the virtual photon energy
  carried by the hadron, z Eh/?, is z 0.5 to
  detect leading pion in the current fragmentation
  region.
• A cut of W gt 1.5 GeV is required to stay away
  from the delta resonance production region.

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Predictions of Collins asymmetry on neutron
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Instrumentation Request for E06-010/E06-011

• Beam
• Polarization above 75
• Energy 6 GeV
• Current 25 µA
• Target (talk by Jian-Ping Chen)
• 40-cm long Rb-K hybrid polarized 3He target at 10
  atm
• gt 40 target polarization with spin-flip period
  of 20 minutes
• Third sets of vertical Helmholtz coils and
  associated laser opticvs for vertical
  polarization

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Instrumentation Request for E06-010/E06-011

• HRS-L spectrometer (talk by A. Camsonne)
• Momentum range 0.6-2.4 GeV/c
• VDC1, VDC2, S1, Short gas Cherenkov, A1, S2M,
  Preshower/shower
• RICH for p/K separation (talk by E. Cisbani)
• Bigbite spectrometer (talk by X. Jiang)
• Electron detection package
• Wire-chamber-2 upgrade (talk by M. Shabestrai)
• Gas Cherenkov (talk by B. Sawatzky)
• Shielding and collimation

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Hall A Transversity Experiments Collaboration
The Institutions
California State Univ., Duke Univ., Florida
International. Univ., Univ. Illinois, JLab, Univ.
Kentucky, 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. Marys Univ.,
Tel Aviv Univ.
Collaboration members (104 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, 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, X. Zheng, S. Zhou,
X. Zong
Cospokesperson Ph.D students
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Manpower and collaboration responsibilities

• 4 Ph.D thesis students stationed at JLab
• Chiranjib Dutta and Allada Kalyan (U. Kentucky)
• Xin Qian (Duke U.) and Youcai Wang (UIUC)
• 3 Postdocs
• Xiaodong Jiang (Rutgers), Yi Qiang (Duke),
  Lingyan Zhu (UIUC)
• Responsibilities
• Duke Bigbite detector tests, 3He target,
  simulations
• FIU HRS detectors
• JLab Bigbite, Polarized 3He target, HRS, DAQ
• INFN RICH and HRS-PID
• UIUC HRS aerogel and RICH, vertical coils,
  Runplan
• Rutgers Bigbite detectors, shielding, trigger
  and DAQ, Runplan
• Temple Bigbite Cherenkov, 3He target
• WM Pol 3He target and cells
• U. Kenntucky Bigbite detector, trigger and DAQ,
  3He target
• U. Virginia Bigbite MWDC, 3He target

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Milestones

• Polarized 3He target
• New oven for cell testing April 1, 2007
• Vertical coils test June 1, 2007
• Cell production 10 by July 1, 2007, 20 by Dec.
  1, 2007
• Laser optics line Nov. 1, 2007
• Complete system test Nov. 1, 2007
• Ready for installation Jan. 1, 2008
• Bigbite detectors
• MWDC-1, MWDC-3 readout check May 30, 2007
• MWDC-2 delivered to JLab June 10, 2007
• Three chambers readout and tracking test Sept.
  1, 2007
• Gas Cherenkov detector commissioning with
  cosmics Oct. 1, 2007
• Integration of MWDC, Cherenkov, Pre/shower Dec.
  1, 2007
• RICH
• RICH frame ready Sept. 2, 2007
• RICH assembled in Rome Nov. 16, 2007
• RICH ready for installation Dec. 10, 2007

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Safety issues

• Safety at the detector lab and Hall-A
• Laser, fire, high pressure cells, electric and
  magnetic fields, oven, radiation, hot surface
• All safety documents will be updated
• All necessary trainings will be arranged
• We will work closely with the JLab safety
  officers to ensure that the proper procedures are
  in place

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Summary

• Significant progress has been made in the
  preparation for the Hall-A transversity
  experiments (Details are presented in later
  talks)
• The responsibilities of the collaborating
  institutes have been clearly defined. Four Ph.D
  students on the transversity experiments are
  stationed at JLab.
• The collaboration anticipates data-taking around
  March 2008. The first transversity measurement on
  polarzied 3He target should provide interesting
  new information on the novel nuclear structure
  functions and fragmentation function.