Yerevan Physics Institute, Yerevan, Armenia.
Institut für Hochenergiephysik, Wien, Austria.
Phys Rev Lett. 2018 Jun 1;120(22):221801. doi: 10.1103/PhysRevLett.120.221801.
A search for a heavy neutral lepton N of Majorana nature decaying into a W boson and a charged lepton is performed using the CMS detector at the LHC. The targeted signature consists of three prompt charged leptons in any flavor combination of electrons and muons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV, with an integrated luminosity of 35.9 fb^{-1}. The search is performed in the N mass range between 1 GeV and 1.2 TeV. The data are found to be consistent with the expected standard model background. Upper limits are set on the values of |V_{eN}|^{2} and |V_{μN}|^{2}, where V_{ℓN} is the matrix element describing the mixing of N with the standard model neutrino of flavor ℓ. These are the first direct limits for N masses above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 GeV.
使用 LHC 上的 CMS 探测器，对质量为 Majorana 型的重中性轻子 N 衰变为 W 玻色子和带电轻子的过程进行了搜索。目标特征由三个在电子和缪子任意味道组合中的 prompt 带电轻子组成。该数据是在质心能量为 13 TeV 的质子-质子碰撞中采集的，积分亮度为 35.9 fb^{-1}。搜索范围是在 1 GeV 到 1.2 TeV 之间的 N 质量范围。结果发现数据与预期的标准模型背景一致。对 V_{eN}|^{2} 和 |V_{μN}|^{2} 值进行了上限设置，其中 V_{ℓN} 是描述 N 与 ℓ 味标准模型中微子混合的矩阵元。这是首次对超过 500 GeV 的 N 质量进行的直接限制，也是在强子对撞机上对低于 40 GeV 的 N 质量进行的首次限制。
