Implications for the ΔAFB anomaly in B¯0→D*+ℓ−ν¯ using a new Monte Carlo event generator
Implications for the ΔAFB anomaly in B¯0→D*+ℓ−ν¯ using a new Monte Carlo event generator
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使用新的蒙特卡罗事件生成器对 B 0 至 D* 中 ÎAFB 异常的影响
DOI：
10.1103/physrevd.107.015011
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发表时间：
2023
影响因子：
5
通讯作者：
Sibidanov, Alexei
中科院分区：
文献类型：
--
作者：
Bhattacharya, Bhubanjyoti;Browder, Thomas E.;Campagna, Quinn;Datta, Alakabha;Dubey, Shawn;Mukherjee, Lopamudra;Sibidanov, Alexei
Belle、BABAR和LHCb最近的B物理实验结果表明，弱B→c带电电流过程中存在新的物理现象（NP）。在这里，我们特别关注衰减模式0→D*+∑r -∑r = e和μ。目前，世界平均的RD和比值与标准模型（SM）的预测相差3.4∑，而最近在前向后不对称测量AFB中观察到一个新的异常，在0→D*+∑μ -∑衰变中。在对2019年Belle数据的分析中发现，Δ (AFB) = AFB (B→D*μ减去v) - AFB （B→D*ev）与SM预测的距离约为4.1 （σ）。在这项工作中，我们探索了Δ¹AFB异常的可能解，并指出了其他角度观测中相关的NP信号。在超出标准模型物理学的情况下，这些角度可观测物之间的相关性必须存在。我们强调Δ型可观测值的重要性，这种可观测值是通过取μ子和电子模的可观测值之差得到的。这些量消除了SM中形状因素的不确定性，并允许对NP进行干净的测试。这些有趣的结果也表明，迫切需要改进0→D*+ +¹¹衰变的模拟和分析技术。在这里，我们还描述了一个新的基于EVTGEN的蒙特卡罗事件生成器工具，我们开发了这个工具来模拟NP特征in0→D*+∑r -v，这是由于SM和NP振幅之间的干扰而产生的。然后，我们讨论了对贝尔II数据的1,5,50和250 ab-1的NP耦合敏感的改进观测值的前景，这些数据似乎非常适合这类测量。
Recent experimental results in B physics from Belle, BABAR, and LHCb suggest new physics (NP) in the weak b → c charged-current processes. Here we focus specifically on the decay modes0→D*+ℓ–with ℓ = e and μ. The world averages of the ratios RD andcurrently differ from the Standard Model (SM) predictions by 3.4σ while recently a new anomaly has been observed in the forward-backward asymmetry measurement, AFB, in0 → D*+μ–decay. It is found that ΔAFB = AFB(B → D*μv) – AFB(B → D*ev) is around 4.1σ away from the SM prediction in an analysis of 2019 Belle data. In this work we explore possible solutions to the ΔAFB anomaly and point out correlated NP signals in other angular observables. These correlations between angular observables must be present in the case of beyond the Standard Model physics. We stress the importance of Δ type observables that are obtained by taking the difference of the observable for the muon and the electron mode. These quantities cancel form-factor uncertainties in the SM and allow for clean tests of NP. These intriguing results also suggest an urgent need for improved simulation and analysis techniques in0 → D*+ℓ–decays. Here we also describe a new Monte Carlo event generator tool based on EVTGEN that we developed to allow simulation of the NP signatures in0 → D*+ℓ–v, which arise due to the interference between the SM and NP amplitudes. We then discuss prospects for improved observables sensitive to NP couplings with 1, 5, 50, and 250 ab–1 of Belle II data, which seem to be ideally suited for this class of measurements.