Eur. Phys. J. Plus (2011) 126: 2
https://doi.org/10.1140/epjp/i2011-11002-4

Regular Article

Transverse spin structure of the nucleon through target single-spin asymmetry in semi-inclusive deep-inelastic (e, e’) reaction at Jefferson Lab

¹ Duke University, NC 27708, Durham, USA
² Penn State University-Berks, PA 19610, Reading, USA
³ Jefferson Lab, VA 23606, Newport News, USA
⁴ Kellogg Radiation Laboratory, California Institute of Technology, CA 91125, Pasadena, USA
⁵ Hampton University, VA 23668, Hampton, USA
⁶ Università di Torino and INFN, Sezione di Torino, I-10125, Torino, Italy
⁷ University of Virginia, VA 22901, Charlottesville, USA
⁸ INFN, Sezione di Roma III, 00146, Roma, Italy
⁹ Lanzhou University, Lanzhou, PRC
¹⁰ Los Alamos National Laboratory, NM, Los Alamos, USA
¹¹ University of Massachusetts, MA 01003, Amherst, USA
¹² China Institute of Atomic Energy, Beijing, PRC
¹³ Huangshan University, Huangshan, PRC
¹⁴ Temple University, PA 19122, Philidalphia, USA
¹⁵ School of Physics, Peking University, Beijing, PRC
¹⁶ University of Illinois at Urbana-Champaign, IL 61801, Urbana, USA
¹⁷ Institute for Theoretical Physics, Universität Tübingen, D-72076, Tübingen, Germany
¹⁸ Syracuse University, NY 13244, Syracuse, USA
¹⁹ Tsinghua University, Beijing, PRC
²⁰ University of Science and Technology, Hefei, PRC

Received: 19 September 2010
Accepted: 28 October 2010
Published online: 12 January 2011

Abstract

Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to perform precision studies of the transverse spin and transverse-momentum-dependent structure in the valence quark region for both the proton and the neutron. In this paper, we focus our discussion on a recently approved experiment on the neutron as an example of the precision studies planned at JLab. The new experiment will perform precision measurements of target Single-Spin Asymmetries (SSA) from semi-inclusive electro-production of charged pions from a 40 cm long transversely polarized ³He target in deep-inelastic-scattering kinematics using 11 and 8.8 GeV electron beams. This new coincidence experiment in Hall A will employ a newly proposed solenoid spectrometer (SoLID). The large acceptance spectrometer and the high polarized luminosity will provide precise 4D (x , z , P_T and Q²) data on the Collins, Sivers, and pretzelosity asymmetries for the neutron through the azimuthal angular dependence. The full 2 azimuthal angular coverage in the lab is essential in controlling the systematic uncertainties. The results from this experiment, when combined with the proton Collins asymmetry measurement and the Collins fragmentation function determined from the e⁺e^- collision data, will allow for a quark flavor separation in order to achieve a determination of the tensor charge of the d quark to a 10% accuracy. The extracted Sivers and pretzelosity asymmetries will provide important information to understand the correlations between the quark orbital angular momentum and the nucleon spin and between the quark spin and nucleon spin.