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Test of lepton flavor universality in B±→K±μ+μ− and B±→K±e+e− decays in proton-proton collisions at s=13TeV
Reports on Progress in Physics ( IF 19.0 ) Pub Date : 2024-07-03 , DOI: 10.1088/1361-6633/ad4e65
The Cms Collaboration 1
Affiliation  

A test of lepton flavor universality in B±K±μ+μ and B±K±e+e decays, as well as a measurement of differential and integrated branching fractions of a nonresonant B±K±μ+μ decay are presented. The analysis is made possible by a dedicated data set of proton-proton collisions at s=13TeV recorded in 2018, by the CMS experiment at the LHC, using a special high-rate data stream designed for collecting about 10 billion unbiased b hadron decays. The ratio of the branching fractions B(B±K±μ+μ) to B(B±K±e+e) is determined from the measured double ratio R(K) of these decays to the respective branching fractions of the B±J/ψK± with J/ψμ+μ and e+e decays, which allow for significant cancellation of systematic uncertainties. The ratio R(K) is measured in the range 1.1<q2<6.0GeV2 , where q is the invariant mass of the lepton pair, and is found to be R(K)=0.780.23+0.47 , in agreement with the standard model expectation R(K)1 . This measurement is limited by the statistical precision of the electron channel. The integrated branching fraction in the same q 2 range, B(B±K±μ+μ)=(12.42±0.68)×108 , is consistent with the present world-average value and has a comparable precision.

中文翻译:


s=13TeV 质子-质子碰撞中 B±→K±μ+μ− 和 B±→K±e+e− 衰变中轻子味道普遍性的测试



轻子味道普遍性的测试 乙± → K ± μ + μ -和 乙± → K ± e + e -衰减,以及非谐振的微分和积分分支分数的测量 乙± → K ± μ + μ -呈现衰变。 该分析是通过质子-质子碰撞的专用数据集实现的 s = 13 TeV大型强子对撞机的 CMS 实验于 2018 年记录,使用了一种特殊的高速数据流,旨在收集约 100 亿次无偏 b 强子衰变。支化分数的比率 乙(乙± → K ± μ + μ - )到 乙(乙± → K ± e + e - )由测量的双倍比确定右( K )这些衰减到各自的支化分数 乙± → J / ψ K ±和<t前数学 id=261> J / ψ → μ + μ -和 e + e -衰减,从而可以显着消除系统不确定性。比例右( K )是在范围内测量的1.1 < q 2 < 6.0 GeV 2 , 在哪里q是轻子对的不变质量,被发现为右( K ) = 0.78 - 0.23 + 0。47 ,与标准模型预期一致右( K ) ≈ 1 。该测量受到电子通道统计精度的限制。同一分支中的综合支化分数q 2 个范围, 乙(乙± → K ± μ + μ - ) = ( 12.42 ± 0.68 ) × 10 - 8 ,与目前世界平均值一致,具有可比精度。
更新日期:2024-07-03
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