论文标题
CMS实验的最新结果
Recent results on $B \to μ^+ μ^-$ decays with the CMS experiment
论文作者
论文摘要
报告了$ b \至μ^+μ^ - $ $与CMS实验的衰落，使用61 fb $^{ - 1} $在LHC运行期间记录的数据的数据1和2016年记录的数据。通过改进的MUON识别算法，并精制了未链接的最大可能性拟合方法，并在decay $ b_s^0 peans $ b_s^0 \ use-5^use-5^us^use^^use^^use^use-i^use-5^use-usever-5 thertive IS^0^+μ^。偏差。它的分支分数测量为bf（$ b^0_s \至μ^+μ^ - $）= [2.9 +/- 0.7（exp）+/- 0.2（frag）] $ \ times 10^{ - 9} $，第一个错误是组合的统计和系统误差概率和第二个错误的概率和$ b^0_的$ b^0_s $ b^0_s $ b^0_s $ b^0_。 $ b^0_s \toμ^+μ^ - $有效寿命为$τ_{μ^+μ^ - } = 1.70^{+ 0.61} _ { - 0.44} $ ps。找不到衰减的证据$ b^0 \至μ^+μ^ - $ $ $ $^$（$ b^0 \toμ^+μ^ - $）<3.6 $ \ times 10^{ - 10} $（在95％的置信度）。所有结果都与粒子物理的标准模型一致。
Results on $B \to μ^+ μ^-$ decays with the CMS experiment are reported, using 61 fb$^{-1}$ of data recorded during LHC Run 1 and 2016. With an improved muon identification algorithm and refined unbinned maximum likelihood fitting methods, the decay $B_s^0 \to μ^+ μ^-$ is observed with a significance of 5.6 standard deviations. Its branching fraction is measured to be BF($B^0_s \to μ^+ μ^-$) = [2.9+/-0.7(exp)+/-0.2(frag)]$\times 10^{-9}$, where the first error is the combined statistical and systematic uncertainty and the second error quantifies the uncertainty of the $B^0_s$ and $B^+$ fragmentation probability ratio. The $B^0_s \to μ^+ μ^-$ effective lifetime is $τ_{μ^+ μ^-} =1.70^{+0.61}_{-0.44}$ps. No evidence for the decay $B^0 \to μ^+ μ^-$ is found and an upper limit of BF($B^0 \to μ^+ μ^-$) < 3.6$\times 10^{-10}$ (at 95% confidence level) is determined. All results are consistent with the standard model of particle physics.
