标题： 使用 ATLAS 探测器观测 $\sqrt{s}=$13 TeV 的 $t\bar{t}γγ$ 产生 显示英文标题

标题： Observation of $t\bar{t}γγ$ production at $\sqrt{s}=$13 TeV with the ATLAS detector

摘要： 本文介绍了首次观测到的顶夸克对与两个光子（$t\bar{t}\gamma\gamma$）关联产生的事件。 该测量是在单 lepton 衰变道中进行的，使用了由 ATLAS 探测器在大型强子对撞机上收集的质子-质子碰撞数据。 这些数据对应于在 13 TeV 中心-of-mass 能量下运行 2 期间记录的 140 fb$^{-1}$的综合亮度。 基于粒子级动力学标准定义的有限相空间中的生产横截面$t\bar{t}\gamma\gamma$测量值为$2.42^{+0.58}_{-0.53}\, \text{fb}$，对应的观察显著性为 5.2 个标准差。 此外，还确定了$t\bar{t}\gamma\gamma$与一个光子关联的顶夸克对生产的横截面比值，得到$(3.30^{+0.70}_{-0.65})\times 10^{-3}$。 显示英文摘要

摘要： This paper presents the first observation of top-quark pair production in association with two photons ($t\bar{t}\gamma\gamma$). The measurement is performed in the single-lepton decay channel using proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider. The data correspond to an integrated luminosity of 140 fb$^{-1}$ recorded during Run 2 at a centre-of-mass energy of 13 TeV. The $t\bar{t}\gamma\gamma$ production cross section, measured in a fiducial phase space based on particle-level kinematic criteria for the lepton, photons, and jets, is found to be $2.42^{+0.58}_{-0.53}\, \text{fb}$, corresponding to an observed significance of 5.2 standard deviations. Additionally, the ratio of the production cross section of $t\bar{t}\gamma\gamma$ to top-quark pair production in association with one photon is determined, yielding $(3.30^{+0.70}_{-0.65})\times 10^{-3}$.