arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1102.5737nucl-exhep-ex
收藏

$\mathbf{Q^2 = 4.0}$、4.8和5.6 GeV $\mathbf{^2}$下质子形状因子比数据的最终分析

Final Analysis of Proton Form Factor Ratio Data at $\mathbf{Q^2 = 4.0}$, 4.8 and 5.6 GeV$\mathbf{^2}$

A. J. R. Puckett, E. J. Brash, O. Gayou, M. K. Jones, L. Pentchev, C. F. Perdrisat, V. Punjabi, K. A. Aniol, T. Averett, F. Benmokhtar, W. Bertozzi, L. Bimbot, … 展开作者

A. J. R. Puckett, E. J. Brash, O. Gayou, M. K. Jones, L. Pentchev, C. F. Perdrisat, V. Punjabi, K. A. Aniol, T. Averett, F. Benmokhtar, W. Bertozzi, L. Bimbot, J. R. Calarco, C. Cavata, Z. Chai, C. -C. Chang, T. Chang, J. P. Chen, E. Chudakov, R. De Leo, S. Dieterich, R. Endres, M. B. Epstein, S. Escoffier, K. G. Fissum. H. Fonvieille, S. Frullani, J. Gao, F. Garibaldi, S. Gilad, R. Gilman, A. Glamazdin, C. Glashausser, J. Gomez, J. -O. Hansen, D. Higinbotham, G. M. Huber, M. Iodice, C. W. de Jager, X. Jiang, M. Khandaker, S. Kozlov, K. M. Kramer, G. Kumbartzki, J. J. LeRose, D. Lhuillier, R. A. Lindgren, N. Liyanage, G. J. Lolos, D. J. Margaziotis, F. Marie, P. Markowitz, K. McCormick, R. Michaels, B. D. Milbrath, S. K. Nanda, D. Neyret, N. M. Piskunov, R. D. Ransome, B. A. Raue, R. Roché, M. Rvachev, A. Saha, C. Salgado, S. Sirca, I. Sitnik, S. Strauch, L. Todor, E. Tomasi-Gustafsson, G. M. Urciuoli, H. Voskanyan, K. Wijesooriya, B. B. Wojtsekhowski, X. Zheng, L. Zhu

摘要:

精确测量质子电磁形状因子比$R = μ_p G_E^p/G_M^p$使用极化转移方法在杰斐逊实验室已经彻底改变了核子结构的理解,揭示了强烈的减少与$Q^2 \gtrsim 1$ GeV $^2$,与以前提取的$R$从截面测量的动量转移$Q^2$。特别是,极化转移的结果暴露了单光子交换近似的适用性的局限性,并强调了夸克轨道角动量在核子结构中的作用。杰斐逊实验室A厅的GEp-II实验在3.5 GeV $^2 \le Q^2 \le 5.6$ GeV $^2$范围内的四个$Q^2$值下测量$R$。最初发表的GEP-II结果与最近在更高的$Q^2$下测量的结果之间可能存在差异,这促使对GEP-II数据进行新的分析。本文介绍了GEp-II实验的最终结果,包括新分析的细节,设备的扩展描述和自最初出版以来理论进展的概述。最终分析的关键结果是$R$结果的系统性增加,提高了高$Q^2$区域中偏振传输数据的一致性。这种增加是由于改进了弹性事件的选择,这在很大程度上消除了原始分析低估的非弹性污染的系统影响。

英文摘要:

Precise measurements of the proton electromagnetic form factor ratio $R = μ_p G_E^p/G_M^p$ using the polarization transfer method at Jefferson Lab have revolutionized the understanding of nucleon structure by revealing the strong decrease of $R$ with momentum transfer $Q^2$ for $Q^2 \gtrsim 1$ GeV$^2$, in strong disagreement with previous extractions of $R$ from cross section measurements. In particular, the polarization transfer results have exposed the limits of applicability of the one-photon-exchange approximation and highlighted the role of quark orbital angular momentum in the nucleon structure. The GEp-II experiment in Jefferson Lab's Hall A measured $R$ at four $Q^2$ values in the range 3.5 GeV$^2 \le Q^2 \le 5.6$ GeV$^2$. A possible discrepancy between the originally published GEp-II results and more recent measurements at higher $Q^2$ motivated a new analysis of the GEp-II data. This article presents the final results of the GEp-II experiment, including details of the new analysis, an expanded description of the apparatus and an overview of theoretical progress since the original publication. The key result of the final analysis is a systematic increase in the results for $R$, improving the consistency of the polarization transfer data in the high-$Q^2$ region. This increase is the result of an improved selection of elastic events which largely removes the systematic effect of the inelastic contamination, underestimated by the original analysis.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑