Bulletin of the American Physical Society
2011 Fall Meeting of the APS Division of Nuclear Physics
Volume 56, Number 12
Wednesday–Saturday, October 26–29, 2011; East Lansing, Michigan
Session NE: Hadronic Physics III |
Hide Abstracts |
Chair: Mary Alberg, Seattle University Room: 103AB |
Saturday, October 29, 2011 10:30AM - 10:42AM |
NE.00001: New Results and Future Experiments on Double Spin Asymmetry $A_{LT}$ in DIS Pion Electroproduction on $^{3}$He Jin Huang We report the final results for the first measurement of the double-spin asymmetry $A_{LT}$ of charged pion electroproduction in deep inelastic electron scattering on a transversely polarized $^{3}$He target, obtained by reversing the electron beam helicity at 30 Hz. The corresponding neutron $A_{LT}$ asymmetries were extracted. The kinematics were focused on the valence quark region, $x\sim0.16 \mbox{-}0.35$, with $Q^{2}\sim1.4\mbox{-}2.7\,\textrm{GeV}^{2}$. These new data probe the transverse momentum dependent parton distribution function $g_{1T}^{q}$ and therefore provide direct access to quark spin-orbit correlations. This experiment has laid the foundation for future high-precision measurements using an approved large acceptance spectrometer, which will also be discussed in this talk. [Preview Abstract] |
Saturday, October 29, 2011 10:42AM - 10:54AM |
NE.00002: Results from Single Spin Asymmetries Measurement in Semi-Inclusive DIS Reaction on a Transversely Polarized 3He Target Kalyan Allada Jefferson Lab experiment E06-010 measured the target single spin asymmetries in semi-inclusive deep inelastic $^{3}He^{\uparrow}(e,e'\pi^{\pm}/K^{\pm})X$ reactions on a transversely polarized $^3He$ target. The measured asymmetry ($A_{UT}$) is sensitive to nucleon transversity and Sivers distribution functions. The kinematics were chosen to be in the valence quark region with $x\sim 0.16 - 0.35$ and $Q^2 \sim 1.4 - 2.7 GeV^2$. The Collins moment, which is sensitive to the transversity, and the Sivers moment, which is sensitive to the orbital motion of the quarks, were extracted using the azimuthal angular dependence of the measured asymmetries. This data, when combined with the data from other experiments on the transversely polarized proton and deuteron targets, will help in extracting the nucleon transversity and Sivers distribution functions through a global analysis. We will present the results of pion asymmetries from this experiments and future plans for high precision experiments in Hall-A. [Preview Abstract] |
Saturday, October 29, 2011 10:54AM - 11:06AM |
NE.00003: Pair-Symmetric Background of Spin Asymmetries of the Nucleon Experiment (Jefferson Lab E07-003) Luwani Ndukum The Spin Asymmetries of the Nucleon Experiment (SANE) at the Thomas Jefferson Lab National Accelerator Facility measured inclusive double spin asymmetries by scattering longitudinally polarized electrons on a longitudinally and transversely polarized NH3 target. The measurements were done at momentum transfer of 2.5 $\le $ Q$^{2} \le $ 6.5 GeV$^{2}$ and Bjorken x of 0.3 $\le $ x $\le $ 0.8. Data were also taken at 0.2 $<$ x $<$ 0.3. Preliminary analysis of the pair-symmetric background used to extract asymmetries from this low x data will be discussed. [Preview Abstract] |
Saturday, October 29, 2011 11:06AM - 11:18AM |
NE.00004: The Spin Asymmetries of the Nucleon Experiment Whitney Armstrong The Spin Asymmetries of the Nucleon Experiment (SANE) measured the virtual Compton scattering asymmetries, $A_1$ and $A_2$, from which the spin structure functions of the proton, $g_1$ and $g_2$, can be obtained. The kinematics for these measurements are in a range of Bjorken $x$, $0.3 < x < 0.8$, where extraction of the twist three matrix element $d_2^p $ (an integral with respect to $x$ of $2g_1+ 3g_2$ weighted by $x^2$) is most sensitive. The observable, $d_2$, is a measure of the average restoring Lorentz color force experienced by a quark inside a polarized nucleon after it is struck by a virtual photon in electron Deep Inelastic Scattering (DIS)[1]. The data was taken at the Thomas Jefferson National Accelerator Facility's Hall C, using beam energies of $4.7$ and $5.9~GeV$, probing the nucleon at scales ranging from $Q^2 = 2.5~GeV^2$ up to $Q^2 = 6.5~GeV^2$. In this polarized electron scattering off a polarized proton target experiment two inclusive double spin asymmetries, $A_\parallel$ and $A_{80}$ ($\simeq A_\perp$) were measured using the BETA detector. BETA is a device without magnetic momentum dispersion that consists of a front scintillator hodoscope followed by a threshold gas Cherenkov counter, a Lucite hodoscope and a large array of lead glass detectors. In addition to motivating the physics of the proton's spin structure we shall discuss the analysis and present preliminary results.\\[0pt] [1] M. Burkardt, AIP Conf. Proc. 1149, 62 (2009) [arXiv:0902.0163 [hep-ph]]. [Preview Abstract] |
Saturday, October 29, 2011 11:18AM - 11:30AM |
NE.00005: Extracting the photoproduction cross section off the neutron $\gamma $n$\to \pi ^{-}$p from deuteron data with FSI effects Igor Strakovsky, Vladimir E. Tarasov, William Briscoe, Haiyan Gao, Alexander E. Kudryavtsev The incoherent pion photoproduction $\gamma $d$\to \pi ^{-}$pp is considered theoretically in a wide energy region below 2.7 GeV. The model applied contains the impulse approximation (IA) as well as the NN- and $\pi $N-FSI. The aim of the project is to study a reliable way for getting the information on elementary $\gamma $n$\to \pi ^{-}$p cross section beyond the IA for $\gamma $d$\to \pi ^{-}$pp. For the elementary $\gamma $N$\to \pi $N, NN$\to $NN, and $\pi $N$\to \pi $N amplitudes, the results of the GW DAC are used. There are no additional theoretical constraints. The calculated d$\sigma $/d$\Omega (\gamma $d$\to \pi ^{-}$pp) are compared with existing data. The procedure used to extract information on the d$\sigma $/d$\Omega (\gamma $n$\to \pi ^{-}$p) on the neutron from the deuteron data using the FSI correction factor R is discussed. The results show a sizeable FSI effect R $\ne $ 1 from S-wave part of pp-FSI at small angles close to $\theta _{1}\sim $0: this region narrows as the photon energy increases. At larger angles, the effect is small ($\vert $R-1$\vert <<$1) and agrees with estimations of FSI in the Glauber approach. [Preview Abstract] |
Saturday, October 29, 2011 11:30AM - 11:42AM |
NE.00006: Single and double polarization asymmetries from deeply virtual $\pi^0$ production with a longitudinally polarized proton target Andrey Kim Deeply virtual exclusive reactions such as $\pi^0$ meson production with large $\gamma$ virtuality $Q^2$ offer an opportunity to explore the nucleon structure and access information about quark position and angular momentum distributionsin nucleon, as described in terms of the Generalized Parton Distributions (GPDs). Cross-section measurements of $\pi^0$ production recently have been carried out at Jefferson Lab in the DIS regime. Measurements of polarization observables provide additional information of the production mechanism due to interference effects. Preliminary results will be discussed on single and double polarization asymmetries from data recently obtained using the highly polarized CEBAF electron beam, a longitudinally polarized $NH_3$ target, and the CEBAF Large Acceptance Spectrometer (CLAS) equipped with a high granularity electromagnetic calorimeter. The asymmetries are highly sensitive to the different kinematics covered in the measurement. Preliminary results for different $Q^2$, $x_B$ and $t$ ranges will be presented. [Preview Abstract] |
Saturday, October 29, 2011 11:42AM - 11:54AM |
NE.00007: Quark Propagation and Hadron Formation in Cold Nuclear Matter Raphael Dupre After four decades of dedicated experiments, knowledge on the hadronization dynamic remain very limited, this is due to both the model and measurement uncertainties. The question is whether the hadron attenuation observed is due to gluon emission by the colored parton or due to the absorption of colorless prehadron or both. Clarifying this issue is the main goal of several recent experiments. In this talk, I will present recent results from a Jefferson Lab experiment, data were taken using a 5 GeV electron beam on various nuclear targets (deuterium, carbon, aluminum, iron, tin and lead). The large acceptance spectrometer, CLAS in Hall B, permits to detect the scattered electron in coincidence with produced hadrons over a large kinematic range. The focus of the talk will be on semi-inclusive negative pion measurement and their implications on various existing hadronization model. I will conclude with the opportunities these data offers to extract information on the time scale of hadronization and on the gluon content of nuclei. [Preview Abstract] |
Saturday, October 29, 2011 11:54AM - 12:06PM |
NE.00008: Target Single Spin Asymmetry in DVCS Erin Seder The target single spin asymmetry in the reaction ep$\rightarrow$ ep$\gamma$ is directly proportional to the imaginary part of the Deeply Virtual Compton Scattering (DVCS) amplitude and gives access to a combination of the Generalized Parton Distributions (GPDs) \~H, H, and E. We present the preliminary single spin asymmetry studies from the eg1-dvcs experiment conducted in Hall B of Jefferson Lab using the Continuous Electron Beam Accelerator Facility's (CEBAF) 6 GeV electron beam, a polarized solid-state \(^{14}NH_{3}\) target, and the CEBAF Large Acceptance Spectrometer (CLAS) equipped with an additionally built Inner Calorimeter (IC). The high statistics collected allow for detailed studies of the Q\(^2\), x\(_B\) and t dependences of the DVCS amplitude over a wide range of kinematics. [Preview Abstract] |
Saturday, October 29, 2011 12:06PM - 12:18PM |
NE.00009: Investigation of Angular Distributions of Drell-Yan Dimuons in p+p and p+d Interactions with the E906/SeaQuest Experiment Christine Aidala Striking $cos 2\phi$ dependences in pion-induced Drell-Yan measurements were first observed in the 1980s, and proton- induced Drell-Yan measurements by the Fermilab E866 experiment on deuterium and hydrogen targets published in 2007 and 2009 reported smaller but non-zero azimuthal dependences of the Drell-Yan pairs. These azimuthal effects have been attributed to a correlation between the spin and transverse momentum of transversely polarized quarks within an unpolarized nucleon, parametrized by the Boer-Mulders transverse-momentum-dependent distribution function, with additional contributions from QCD effects. With data taking planned to start in the summer of 2011, the E906/SeaQuest experiment will use a 120 GeV/c proton beam extracted from the Fermilab Main Injector on liquid hydrogen and deuterium targets, extending the kinematic coverage of its predecessor experiment E866 to higher parton momentum fraction. Measurement of the dimuon angular distributions will also allow the Lam-Tung relation to be tested in an extended kinematic range compared to E866. The status of data taking and prospects for measurement of the angular distributions of Drell-Yan pairs will be presented. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700