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arXiv 1611.07375hep-ex
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NA48/2实验中$K^{\pm}\rightarrow πμμ$衰变中轻子数破坏和共振的计算

Searches for Lepton Number Violation and resonances in the $K^{\pm}\rightarrow πμμ$ decays at the NA48/2 experiment

Karim Massri

摘要:

CERN的NA 48/2实验在2003- 2004年收集了大量的带电K介子衰变到多个带电粒子的末态的样品。本文报道了从该样品中得到的轻子数破坏衰变$K^{\pm}\toπ^{\mp}μ^{\pm}μ^{\pm}$速率的一个新的上限:$\mathcal{B}(K^{\pm}\toπ^{\mp}μ^{\pm}μ^{\pm})<8.6 \times 10^{-11}$ at 90\% CL。在质量和寿命可达的范围内,给出了$K^{\pm}\toπμμ$衰变(包括重中性轻子~ $N_4$和暴胀子~ $χ$)中两体共振的计算结果。在没有信号的情况下,将分支比~ $\mathcal{B}(K^{\pm}\toμ^{\pm}N_4)\mathcal{B}(N_4\toπμ)$和$\mathcal{B}(K^{\pm}\toπ^{\pm}χ)\mathcal{B}(χ\toμ^+μ^-)$的乘积设定为共振质量和寿命的函数。对于低于100 μ s的谐振寿命,这些限制在$10^{-10}-10^{-9}$范围内。

英文摘要:

The NA48/2 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2003--2004. A new upper limit on the rate of the lepton number violating decay $K^{\pm}\toπ^{\mp}μ^{\pm}μ^{\pm}$ obtained from this sample is reported: $\mathcal{B}(K^{\pm}\toπ^{\mp}μ^{\pm}μ^{\pm})<8.6 \times 10^{-11}$ at 90\% CL. Searches for two-body resonances in the $K^{\pm}\toπμμ$ decays (including heavy neutral leptons~$N_4$ and inflatons~$χ$) in the accessible range of masses and lifetimes are also presented. In the absence of a signal, upper limits are set on the products of branching ratios~$\mathcal{B}(K^{\pm}\toμ^{\pm}N_4)\mathcal{B}(N_4\toπμ)$ and $\mathcal{B}(K^{\pm}\toπ^{\pm}χ)\mathcal{B}(χ\toμ^+μ^-)$ as functions of the resonance mass and lifetime. These limits are in the $10^{-10}-10^{-9}$ range for resonance lifetimes below 100~ps.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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