arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1901.03584hep-ex
收藏

用ATLAS探测器测量$\sqrt{s}=13$ TeV质子-质子碰撞的$t\bar{t}Z$和$t\bar{t}W$截面

Measurement of the $t\bar{t}Z$ and $t\bar{t}W$ cross sections in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

ATLAS Collaboration

摘要:

利用ATLAS探测器收集的积分光度的$36.1$ fb $^{-1}$测量了质心能量为13 TeV的质子-质子碰撞中顶夸克对($t\bar{t}$)与矢量玻色子($W$,$Z$)的伴随产生.事件在具有两个相同或相反符号的轻子(电子或μ子)、三个轻子或四个轻子的通道中被选择,并且每个通道被进一步划分为多个区域以最大化测量的灵敏度。$t\bar{t}Z$和$t\bar{t}W$生产截面使用对所有区域的组合拟合同时测量。生产截面的最佳拟合值为$σ_{t\bar{t}Z} = 0.95 \pm 0.08_{\mathrm{stat.}} \pm 0.10_{\mathrm{syst.}}$ pb和$σ_{t\bar{t}W} = 0.87 \pm 0.13_{\mathrm{stat.}} \pm 0.14_{\mathrm{syst.}}$ pb,与标准模型预测一致。$t\bar{t}Z$横截面的测量被用于设置对修改$t\bar{t}Z$顶点的有效场论算子的约束。

英文摘要:

A measurement of the associated production of a top-quark pair ($t\bar{t}$) with a vector boson ($W$, $Z$) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using $36.1$ fb$^{-1}$ of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The $t\bar{t}Z$ and $t\bar{t}W$ production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are $σ_{t\bar{t}Z} = 0.95 \pm 0.08_{\mathrm{stat.}} \pm 0.10_{\mathrm{syst.}}$ pb and $σ_{t\bar{t}W} = 0.87 \pm 0.13_{\mathrm{stat.}} \pm 0.14_{\mathrm{syst.}}$ pb in agreement with the Standard Model predictions. The measurement of the $t\bar{t}Z$ cross section is used to set constraints on effective field theory operators which modify the $t\bar{t}Z$ vertex.

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。

↑