论文标题
观察$τ$ Lepton对在超递核核核碰撞中与CMS实验的碰撞和LHC上$（g-2）_τ$的第一个限制的观察
Observation of $τ$ lepton pair production in ultraperipheral nucleus-nucleus collisions with the CMS experiment and the first limits on $(g-2)_τ$ at the LHC
论文作者
论文摘要
提出了对$τ$ Lepton对产生的首次观察到超递核核核碰撞（纯量子电动力学（QED）过程）中的首次观察。该测量是基于CMS实验收集的数据样本，其每个核子质量中心能量为$ 5.02〜 \ Mathrm {TEV} $，对应于$ 404〜μ \ MATHRM {B}^{ - 1} $的集成发光度。观察到$γγ\toτ^{+}τ^{ - } $产生的统计意义至少为$τ^{+}τ^{ - } $事件的五个标准偏差，带有若干和三个带电的Hadrons。横截面在一个基准相空间区域进行测量，发现为$σ（γγ\toτ^{+}τ^{ - }）= 4.8 \ pm 0.6 \，（\ Mathrm {stat}）\ pm 0.5 \ pm pm}该测量基于LHC核计划的预期综合光度的一小部分，它为对$τ$ Lepton的异常磁矩做出更精确的确定的潜力，目前受到限制不佳。
The first observation of $τ$ lepton pair production in ultraperipheral nucleus-nucleus collisions, a pure quantum electrodynamics (QED) process, is presented. The measurement is based on a data sample collected by the CMS experiment at a per nucleon center-of-mass energy of $5.02~\mathrm{TeV}$, and corresponding to an integrated luminosity of $404~μ\mathrm{b}^{-1}$. The $γγ\toτ^{+}τ^{-}$ production is observed with a statistical significance of at least five standard deviations for $τ^{+}τ^{-}$ events with a muon and three charged hadrons in the final state. The cross section is measured in a fiducial phase space region, and is found to be $σ(γγ\toτ^{+}τ^{-}) = 4.8\pm 0.6\,(\mathrm{stat})\pm 0.5\,(\mathrm{syst})~μ\mathrm{b}$, in agreement with leading-order QED predictions. The measurement, based on a small fraction of the expected integrated luminosity of the LHC nuclear program, establishes the potential for a substantially more precise determination of the anomalous magnetic moment of the $τ$ lepton, which is currently poorly constrained.
