Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland.
Phys Rev Lett. 2010 Dec 17;105(25):252001. doi: 10.1103/PhysRevLett.105.252001. Epub 2010 Dec 13.
A precision measurement of the top quark mass m(t) is obtained using a sample of tt events from pp collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m(t) and a parameter Δ(JES) used to calibrate the jet energy scale in situ. Using a total of 1087 events in 5.6 fb(-1) of integrated luminosity, a value of m(t)=173.0 ± 1.2 GeV/c(2) is measured.
采用 CDF II 探测器，利用费米实验室 Tevatron 质子-质子对撞产生的 tt 事例样本，对顶夸克质量 mt 进行了精密测量。所选择的事例要求有一个电子或缪子、大的横向能量缺失和 4 个高能量喷注，其中至少有一个喷注被标记为来自 b 夸克。采用矩阵元方法，利用拟蒙特卡罗积分计算似然值，其中考虑了有限的探测器分辨率和喷注质量效应。事件似然值是 mt 和一个参数 Δ(JES)的函数，Δ(JES)用于对喷注能量标度进行原位校准。在 5.6 fb(-1)积分亮度下，共有 1087 个事例，测量得到 mt=173.0 ± 1.2 GeV/c(2)。
