University of Birmingham Search for long-lived scalar particles in B+ k+ (+-) decays
University of Birmingham Search for long-lived scalar particles in B+ k+ (+-) decays
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伯明翰大学在 B k (-) 衰变中寻找长寿命标量粒子
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通讯作者：
A. Szczurek
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作者：
V. Gonçalves;R. Maciuła;R. Pasechnik;A. Szczurek
进行长寿命标量粒子χ的搜索，在pp碰撞数据中寻找x → μ π μ −的衰变B π → K π χ，对应于3 fb − 1的积分光度，由LHC B实验在质量中心能量为π s p1/4 7和8 TeV时收集。由隐藏扇形模型预测的这个新的标量粒子被假设具有较窄的宽度。这个信号会表现为在标准模型背景下的双μ子不变质量分布中的过量。在质量250 <m2 × m2 < 4700 MeV = c2和寿命0的可接近范围内没有观察到明显的过量。1 < τ π χ π < 1000 ps。在95%的置信水平下，分支分数B <$B <$→ K <$χ <$μ <$μ − <$$>的上限被设定为m <$χ <$和τ <$χ <$的函数，在2 × 10 − 10和10 − 7之间变化。这是迄今为止最严格的限制。的限制被解释的上下文中的模型与轻暴胀粒子。
A search for a long-lived scalar particle χ is performed, looking for the decay B þ → K þ χ with χ → μ þ μ − in pp collision data corresponding to an integrated luminosity of 3 fb − 1 , collected by the LHCb experiment at center-of-mass energies of ffiffiffi s p ¼ 7 and 8 TeV. This new scalar particle, predicted by hidden sector models, is assumed to have a narrow width. The signal would manifest itself as an excess in the dimuon invariant mass distribution over the Standard Model background. No significant excess is observed in the accessible ranges of mass 250 < m ð χ Þ < 4700 MeV =c 2 and lifetime 0 . 1 < τ ð χ Þ < 1000 ps. Upper limits on the branching fraction B ð B þ → K þ χ ð μ þ μ − ÞÞ at 95% confidence level are set as a function of m ð χ Þ and τ ð χ Þ , varying between 2 × 10 − 10 and 10 − 7 . These are the most stringent limits to date. The limits are interpreted in the context of a model with a light inflaton particle.