演示一种测量弹性 $e^\pm p$ 散射中双光子交换效应的新方法
核实验
2013-09-04 v2
摘要
利用非极化和极化散射数据提取的质子电磁形状因子之间的差异，被认为源于双光子交换 (TPE) 效应。然而，TPE 修正的计算具有显著的模型依赖性，且缺乏直接的实验证据。我们展示了一种用于直接进行 比较的新实验技术的结果，该技术有潜力在广泛的 和散射角范围内进行精确测量。我们利用杰斐逊实验室 (Jefferson Lab) 的电子束和 B 厅 (Hall B) 光子标记器产生一束干净但未标记的光子束。该光子束轰击转换箔以产生电子、正电子和光子的混合束。使用弯转磁铁系统 (chicane) 分离并重新组合电子和正电子束，同时光子束被光子阻挡器阻挡。这提供了一束能量从 0.5 到 3.2 GeV 的组合电子和正电子束，轰击液氢靶。大接受度的 CLAS 探测器用于识别和重建弹性散射事件，确定初始轻子能量和散射轻子的符号。数据收集耗时两天，主电子束能量仅为 3.3 GeV，限制了本次运行数据的 和散射角处于较小值。尽管如此，该测量产生的 数据样本统计量与以往最佳测量相当。我们表明，我们可以清晰地识别弹性散射事件，并修正电子和正电子散射接受度的差异。正电子与电子散射的最终比率为：，对应 GeV 和 。
引用
@article{arxiv.1306.2286,
title = {Demonstration of a novel technique to measure two-photon exchange effects in elastic $e^\pm p$ scattering},
author = {M. Moteabbed and M. Niroula and B. A. Raue and L. B. Weinstein and D. Adikaram and J. Arrington and W. K. Brooks and J. Lachniet and Dipak Rimal and M. Ungaro and K. P. Adhikari and M. Aghasyan and M. J. Amaryan and S. Anefalos Pereira and H. Avakian and J. Ball and N. A. Baltzell and M. Battaglieri and V. Batourine and I. Bedlinskiy and R. P. Bennett and A. S. Biselli and J. Bono and S. Boiarinov and W. J. Briscoe and V. D. Burkert and D. S. Carman and A. Celentano and S. Chandavar and P. L. Cole and P. Collins and M. Contalbrigo and O. Cortes and V. Crede and A. D'Angelo and N. Dashyan and R. De Vita and E. De Sanctis and A. Deur and C. Djalali and D. Doughty and R. Dupre and H. Egiyan and L. El Fassi and P. Eugenio and G. Fedotov and S. Fegan and R. Fersch and J. A. Fleming and N. Gevorgyan and G. P. Gilfoyle and K. L. Giovanetti and F. X. Girod and J. T. Goetz and W. Gohn and E. Golovatch and R. W. Gothe and K. A. Griffioen and M. Guidal and N. Guler and L. Guo and K. Hafidi and H. Hakobyan and C. Hanretty and N. Harrison and D. Heddle and K. Hicks and D. Ho and M. Holtrop and C. E. Hyde and Y. Ilieva and D. G. Ireland and B. S. Ishkhanov and E. L. Isupov and H. S. Jo and K. Joo and D. Keller and M. Khandaker and A. Kim and F. J. Klein and S. Koirala and A. Kubarovsky and V. Kubarovsky and S. E. Kuhn and S. V. Kuleshov and S. Lewis and H. Y. Lu and M. MacCormick and I . J . D. MacGregor and D. Martinez and M. Mayer and B. McKinnon and T. Mineeva and M. Mirazita and V. Mokeev and R. A. Montgomery and K. Moriya and H. Moutarde and E. Munevar and C. Munoz Camacho and P. Nadel-Turonski and R. Nasseripour and S. Niccolai and G. Niculescu and I. Niculescu and M. Osipenko and A. I. Ostrovidov and L. L. Pappalardo and R. Paremuzyan and K. Park and S. Park and E. Phelps and J. J. Phillips and S. Pisano and O. Pogorelko and S. Pozdniakov and J. W. Price and S. Procureur and D. Protopopescu and A. J. R. Puckett and M. Ripani and G. Rosner and P. Rossi and F. Sabatié and M. S. Saini and C. Salgado and D. Schott and R. A. Schumacher and E. Seder and H. Seraydaryan and Y. G. Sharabian and E. S. Smith and G. D. Smith and D. I. Sober and D. Sokhan and S. Stepanyan and S. Strauch and W. Tang and C. E. Taylor and Ye Tian and S. Tkachenko and H. Voskanyan and E. Voutier and N. K. Walford and M. H. Wood and N. Zachariou and L. Zana and J. Zhang and Z. W. Zhao and I. Zonta},
journal= {arXiv preprint arXiv:1306.2286},
year = {2013}
}