阈值处 Q^2 = 0.05 GeV^2/c^2 时\pi^0 电产生的分离截面
核实验
2008-11-26 v1
摘要
在光子四动量转移 Q^2= 0.05 GeV^2/c^2 和质心系角度 \theta=90^\circ 的条件下，测量了从阈值到额外质心系能量 40 MeV 范围内质子产生\pi^0 的微分截面 \sigma_0=\sigma_T+\epsilon \sigma_L、\sigma_{LT} 和 \sigma_{TT}。通过额外的平面外极化电子测量，确定了 \sigma_{LT'}。这首次显示了 s 波虚部中高于 \pi^+ 阈值的尖点效应。重子手征微扰理论 (Heavy Baryon Chiral Perturbation Theory) 的预测与这些数据不符。另一方面，MAID 唯象模型对数据的预测稍好，且与动力学模型 DMT 吻合良好。
引用
@article{arxiv.0705.3816,
title = {Separated cross sections in \pi^0 electroproduction at threshold at Q^2 = 0.05 GeV^2/c^2},
author = {M. Weis and P. Bartsch and D. Baumann and J. Bermuth and A. M. Bernstein and K. Bohinc and R. Böhm and M. Ding and M. O. Distler and I. Ewald and J. M. Friedrich and J. Friedrich and M. Kahrau and M. Kohl and K. W. Krygier and A. Liesenfeld and H. Merkel and P. Merle and U. Müller and R. Neuhausen and M. M. Pavan and Th. Pospischil and M. Potokar and G. Rosner and H. Schmieden and M. Seimetz and S. Širca and A. Wagner and Th. Walcher},
journal= {arXiv preprint arXiv:0705.3816},
year = {2008}
}
备注
6 pages, 4 figures