Yerevan Physics Institute, Yerevan, Armenia.
Phys Rev Lett. 2012 Mar 16;108(11):111804. doi: 10.1103/PhysRevLett.108.111804. Epub 2012 Mar 13.
A search for a Higgs boson in the four-lepton decay channel H→ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range of 110<m(H)<600 GeV. The analysis uses data corresponding to an integrated luminosity of 4.7 fb(-1) recorded by the CMS detector in pp collisions at √s=7 TeV from the LHC. Seventy-two events are observed with four-lepton invariant mass m(4ℓ)>100 GeV (with 13 below 160 GeV), while 67.1±6.0 (9.5±1.3) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of ZZ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges of 134-158 GeV, 180-305 GeV, and 340-465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal.
本报告搜索了 Higgs 玻色子在四轻子衰变道 H→ZZ 中的产生，其中每个 Z 玻色子衰变为一对电子或缪子。该搜索涵盖了 110<m(H)<600GeV 范围内的 Higgs 玻色子质量假设。分析使用了 CMS 探测器在 LHC 的 TeV 对撞机上以 √s=7 TeV 记录的 4.7 fb(-1)积分亮度的数据。观测到 72 个四轻子不变质量 m(4ℓ)>100GeV（其中 13 个低于 160GeV）的事件，而背景预期为 67.1±6.0（9.5±1.3）个事件。四轻子质量分布与标准模型背景 ZZ 对产生的预期相符。在 95%置信水平下的上限排除了 134-158GeV、180-305GeV 和 340-465GeV 范围内的标准模型 Higgs 玻色子。在没有信号的情况下，在 119GeV、126GeV 和 320GeV 左右观察到少量事件过剩，使得观测到的限制比预期的要弱。
