"Table 1" of "Measurement of the energy asymmetry in $t\bar{t}j$ production at 13 TeV with the ATLAS experiment and interpretation in the SMEFT framework"

A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using $139\,\mathrm{fb}^{-1}$ of data collected by the ATLAS detector at the Large Hadron Collider during $pp$ collisions at $\sqrt{s}=13\,\text{TeV}$. The observable measures the different probability of top and antitop quarks to have the higher energy as a function of the jet scattering angle with respect to the beam axis. The energy asymmetry is measured in the semileptonic $t\bar{t}$ decay channel, and the hadronically decaying top quark must have transverse momentum above $350\,\text{GeV}$. The results are corrected for detector effects to particle level in three bins of the scattering angle of the associated jet. The measurement agrees with the SM prediction at next-to-leading-order accuracy in quantum chromodynamics in all three bins. In the bin with the largest expected asymmetry, where the jet is emitted perpendicular to the beam, the energy asymmetry is measured to be $-0.043\pm0.020$, in agreement with the SM prediction of $-0.037\pm0.003$. Interpreting this result in the framework of the Standard Model effective field theory (SMEFT), it is shown that the energy asymmetry is sensitive to the top-quark chirality in four-quark operators and is therefore a valuable new observable in global SMEFT fits.本文报道了喷注关联顶夸克对产生过程中能量不对称性的测量结果，该测量使用了大型强子对撞机（Large Hadron Collider）上ATLAS探测器（ATLAS detector）在质心系能量$sqrt{s}=13,mathrm{TeV}$的质子-质子（pp）碰撞中采集的$139,mathrm{fb}^{-1}$积分亮度数据。该可观测量表征了顶夸克与反顶夸克相对于束流轴的喷注散射角作为函数时，二者具有更高能量的概率差异。本次测量选取半轻子衰变的顶夸克对（$tar{t}$）衰变道，且强衰变顶夸克的横向动量需大于350 GeV。研究针对关联喷注散射角的三个分箱，完成了探测器效应修正并将结果外推至粒子真实层面。在三个分箱中，测量结果均与量子色动力学次领头阶精度下的标准模型（Standard Model, SM）预言相符。在喷注与束流垂直的最大预期不对称性分箱中，测得能量不对称性为$-0.043pm0.020$，与标准模型预言的$-0.037pm0.003$一致。在标准模型有效场论（Standard Model Effective Field Theory, SMEFT）框架下诠释该结果时，分析表明能量不对称性对四夸克算符中的顶夸克手征性敏感，因此其是全局标准模型有效场论拟合中极具价值的新型可观测量。