Bulletin of the American Physical Society
2010 Fall Meeting of the APS Division of Nuclear Physics
Volume 55, Number 14
Tuesday–Saturday, November 2–6, 2010; Santa Fe, New Mexico
Session JD: Single Spin Asymmetries and the Structure of the Nucleon |
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Chair: Renee Fatemi, University of Kentucky Room: Sweeny D |
Friday, November 5, 2010 2:00PM - 2:12PM |
JD.00001: Spin Asymmetry of the Nucleon Experiment (SANE) Analysis Overview Jonathan Mulholland The Spin Asymetries of the Nucleon Experiment (SANE) is an inclusive measurement of the parallel and near-perpendicular double spin asymmetries of the proton that provides access to the spin observable, $A_{1}^{p}$ and structure functions, $g_{1}^{p}$ and $g_{2}^{p}$. The experiment ran in early 2009, using the Thomas Jefferson National Facility's polarized electron beam and the University of Virginia's polarized frozen ${}^{14}NH_{3}$ target in Hall C, collecting data in a $Q^2$ region from $2.5$ to $6.5$ $GeV^2$ and a Bjorken $x$ region of $0.3$ to $0.8$. Particle detection was accomplished using the Big Electron Telescope Array (BETA), a novel non-magnetic detector array with a $194$msr acceptance. The experimental motivations and goals will be discussed in the context of current world data on the proton spin structure functions. The experimental methods will be presented along with an overview of the analysis status and results. Current collaboration analysis effort is focused primarily on the proton spin structure functions $g_1$ and $g_2$, but also includes elastic and inelastic asymmetry data taken with the Hall C High Momentum Spectrometer in both single arm mode and in coincidence with BETA. [Preview Abstract] |
Friday, November 5, 2010 2:12PM - 2:24PM |
JD.00002: Preliminary Proton Spin Asymmetry Results from SANE James Maxwell The Spin Asymetries of the Nucleon Experiment (SANE) is a measurement of parallel and near-perpendicular double spin asymmetries in an inclusive electron scattering experiment, with the aim of calculating the spin asymmetry of the proton $A^1_p$ and spin structure function $g^2_p$. Using Thomas Jefferson National Accelerator Facility's polarized electron beam and the University of Virginia's polarized frozen ammonia ($^{14}$NH$_3$) target in Hall C, the experiment ran in 2009, collecting data in a Q$^2$ region from 2.5 to 6.5 GeV$^2$ in a Bjorken $x$ region of 0.3 to 0.8. Particle detection was accomplished using the Big Electron Telescope Array (BETA), a novel non-magnetic detector array with a 194 msr acceptance. This talk will address the progress of the analysis toward the calculation of the proton spin asymmetry and structure functions, including calibration of the BETA detectors, event selection, and preliminary results. [Preview Abstract] |
Friday, November 5, 2010 2:24PM - 2:36PM |
JD.00003: Transverse Single Spin Asymmetries in \textit{J/$\psi $} Production in Polarized p+p Collisions at $\sqrt s $=200 GeV, measured in the PHENIX Detector at RHIC Hussein Al-Ta'ani The measurement of transverse single spin asymmetries ($A_{N})$ gives us an opportunity to probe the quark and gluon structure of transversely polarized nucleons. At RHIC energies, heavy flavor production is dominated by gluon-gluon fusion. Because the gluon transversity is zero, The Collins effect has minimal impact on $A_{N}$ in heavy flavor production. The measurement of $A_{N}$ in heavy flavor production is uniquely sensitive to the gluon Sivers effect which is potentially related to the orbital angular momentum of gluons inside the polarized protons. The latest measurement of transverse SSAs in \textit{J/$\psi $} production is presented. The data were taken by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) during the 2006 and 2008 run in transverse polarized proton+proton collisions at $\sqrt s $=200 GeV. The $p_{T}$ and $x_{F}$ dependencies are studied in rapidity regions -2.2 $<$ y $<$ -1.2, $\vert $y$\vert \quad <$ 0.35, and 1.2 $<$ y $<$ 2.2, and $p_{T}$ up to 6 GeV/c. [Preview Abstract] |
Friday, November 5, 2010 2:36PM - 2:48PM |
JD.00004: ABSTRACT WITHDRAWN |
Friday, November 5, 2010 2:48PM - 3:00PM |
JD.00005: Measurement of Single Target-Spin Asymmetry in Semi-Inclusive Negatively Charged Pion Electroproduction on a Transversely Polarized $^3$He Target as an Effective Neutron Target Chiranjib Dutta We measured the neutron target single spin asymmetry in the semi-inclusive deep inelastic $^3$$He^{\uparrow}(e,e'\pi^{-})X$ reaction using a transversely polarized $^3$He target. The experiment acquired data in Hall A at Jefferson Lab using a 40 cm long polarized $^3$He target and an electron beam of 5.9 GeV. This first measurement on neutron transversity focuses on the valence quark region, $x = 0.13\sim 0.41$, at $Q^2=1.31\sim 3.10~(\mathrm{GeV}/c)^2$. Negatively charged pions were detected in the left high-resolution spectrometer in coincidence with the scattered electrons detected in the BigBite spectrometer. The data from this experiment, when combined with world data, will provide constraints on the Transversity, Sivers distribution functions and Collins fragmentation functions for both $u$-quark and $d$-quark in the valence region. Preliminary results of the neutron Sivers and Collins moments for the negatively charged pions will be presented for the first time with a summary of the polarized $^3$He target performance. [Preview Abstract] |
Friday, November 5, 2010 3:00PM - 3:12PM |
JD.00006: Measurement of Single Target-Spin Asymmetry in Semi-Inclusive Pion Electroproduction on a Transversely Polarized $^3$He Target Xin Qian Measuring parton distribution functions (PDF) which represent the flavor and spin structure of nucleon is important to reveal the information of quantum chromodynamics in the confinement region. In particular, in parton model, the cross-section in the semi-inclusive deep inelastic scattering (SIDIS), can be written as the product of PDF and fragmentation function which describe the parton hadronized process due to color force. The JLab experiment E06-010 is focusing on measuring the target single spin asymmetry in the semi-inclusive deep inelastic $\overrightarrow{^{3}\rm He}(e,e'\pi^{+,-})X$ reaction with a transversely polarized $^3\rm He$ target at JLab Hall A with a 5.89 GeV electron beam. The leading pions and scattered electrons were detected in coincidence by the left High-Resolution Spectrometers ($HRS_L$) at $16^{\circ}$ and BigBite spectrometer at $30^{\circ}$, respectively. Kinematic coverage was focused on the valence quark region, x $\sim$0.1-0.4, at $Q^2$ $\sim$ 1-3 (GeV/c)$^2$. The Collins and Sivers asymmetries of $^3\rm He$ and neutron were extracted. The overview of the experiment and the preliminary results will be presented. [Preview Abstract] |
Friday, November 5, 2010 3:12PM - 3:24PM |
JD.00007: Measurement of Single Spin Asymmetries in Semi-Inclusive DIS reaction $n^{\uparrow}(e, e'\pi^+)X$ using Transversely Polarized $^3$He Target Kalyan Allada Measurement of single-spin asymmetries(SSA) on transversely polarized targets gives an access to several interesting aspects of the transverse spin structure of the nucleon. We recently measured the neutron target SSA in the semi-inclusive deep inelastic reaction, $^{3}He^{\uparrow}(e,e'\pi^{\pm}/K^{\pm})X$, with a transversely polarized $^3$He target. The experiment was performed at the Jefferson Lab Hall A. The produced hadrons were detected in the high-resolution spectrometer in coincidence with the scattered electrons detected by the BigBite spectrometer. The kinematic coverage focuses on the valence quark region, $x = 0.1$ to $0.4$, at $Q^2=1$ to $3~(\mathrm{GeV}/c)^2$. Good particle identification was achieved using a RICH detector, an aerogel Cherenkov counter and time-of-flight detectors, which allowed for clean $\pi^{\pm}$ and $K^{\pm}$ detection. The data from this experiment, when combined with the world data, will provide constraints on the transversity and Sivers distributions on both $u$ and $d$ quarks in the valence region. In this talk we will present the first results of the neutron Collins and Sivers asymmetries in $n^{\uparrow}(e,e'\pi^+)X$ channel and discuss its implications. [Preview Abstract] |
Friday, November 5, 2010 3:24PM - 3:36PM |
JD.00008: Measurement of Single-spin Asymmetry in Charged Kaon Electroproduction on a Transversely Polarized $^{3}$He Target Youcai Wang Data on target single-spin asymmetry in the semi-inclusive deep inelastic $\vec{n}(e,e'K^{\pm})X$ reaction have been taken in Hall A at Jefferson Lab using a transversely polarized $^3$He target and an electron beam of 5.9 GeV. This measurement covers the kinematic region, $x = 0.13\sim 0.41$, at $Q^2=1.3\sim 3.1~ (\mathrm{GeV}/c)^2$. In coincidence with the scattered electrons detected in the large-acceptance BigBite spectrometer, kaons were detected in the high-resolution spectrometer and identified using an aerogel Cherenkov, gas Cherenkov and Ring-Imaging Cherenkov (RICH) detectors together with time-of-flight (TOF) information. The kaon single-spin asymmetry data from this experiment are expected to provide constraints on the flavor dependence of the transversity and the Sivers distribution functions. Results on the kaon single-spin asymmetry will be presented and compared with theoretical calculations. [Preview Abstract] |
Friday, November 5, 2010 3:36PM - 3:48PM |
JD.00009: Probing quark-gluon interactions with transverse polarized scattering Oscar Rondon Transverse polarized inelastic scattering extends the power of the electromagnetic interaction as a probe of nucleon dynamics beyond the leading order regime explored with longitudinally polarized DIS. The latter revealed the surprising result of the ``spin defect'' in the quark contribution to the nucleon spin, obtained from measurements of the leading twist $g_1$ spin structure function (SSF). In transverse polarized scattering, the twist-3 $g_2$ SSF contributes at the same order as $g_1$, so interactions between quarks and gluons can be studied, opening a window on the mechanisms of confinement. In this talk I will report the results of Jefferson Lab's Resonances Spin Structure (RSS) experiment measurement of the moments of $g_2$ and the $d_2$ twist-3 quark matrix element at a four-momentum transfer of 1.3 GeV$^2$. The extension of RSS physics by the related JLab Spin Asymmetries of the Nucleon Experiment - SANE, that covers the momentum transfer range from 2.5 to 6.5 GeV$^2$, will be reviewed. [Preview Abstract] |
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