arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2301.07089hep-phhep-exphysics.acc-ph
收藏

研究 $γγ\to γγ$ 散射在 $e^+e^-$、$e^-e^-$ 和 $γγ$ 聚变机中的问题

Impact of QED backgrounds on light-by-light scattering measurements at $e^+e^-$ and $e^-e^-$ colliders

Novosibirsk State University(新西伯利亚国立大学);Budker Institute of Nuclear Physics(布德刻核物理研究所)

K. I. Beloborodov, T. A. Kharlamova, V. I. Telnov

AI总结:

本文探讨了在 $e^+e^-$、$e^-e^-$ 和 $γγ$ 聚变机中研究 $γγ\to γγ$ 散射过程中存在的严重背景问题。

摘要:

光子弹性散射过程(即光子之间的散射)近年来引起了广泛关注。该过程通过一个循环进行,其中所有带电粒子都对截面贡献。截至目前,该 $γγ\to γγ$ 过程已在德布罗克散射、核库仑场中的光子分裂以及LHC中的离子-离子碰撞中的虚拟光子散射中被实验研究。对进一步研究此过程的期望与高亮度 $e^+e^-$ 聚变机(如SuperKEKb、FCC、CEPC、ILC、CLIC)以及基于康普顿散射的光子-光子聚变机相关。在本文中,我们表明存在一些非常严重的背景过程,其中电子和正电子(真实和虚拟)湮灭产生一对光子飞入探测器,而剩余产物则以小角度飞离探测器。

英文摘要:

The process of elastic scattering of photons ($γγ\to γγ$, light-by-light scattering) has attracted significant interest in recent years as a loop-induced process sensitive to all charged particles. To date, this process has been studied through Delbrück scattering, photon splitting in the nuclear Coulomb field, and ultra-peripheral heavy-ion collisions at the LHC. Future precision measurements are anticipated at high-luminosity $e^+e^-$ colliders (SuperKEKb, FCC, CEPC, ILC, CLIC), their $e^-e^-$ options, and $γγ$ colliders based on the backscattering of laser photons. In this paper, we show that background QED processes severely limit the study of elastic light-by-light scattering at $e^+e^-$ colliders. For the $e^+e^-$ case, the main background arises from $e^+e^-$ annihilation into two photons within the detector acceptance after the initial electron and positron emit hard ISR photons at small angles. Since only two photons with a small total transverse momentum are registered in the detector in both cases, this process effectively mimics the $γγ\to γγ$ signal with a significantly larger cross section at high invariant masses. Other relevant background QED processes for both types of collisions are also comprehensively analyzed and discussed.

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。

↑