标题： 极化$Λ_b$重子衰变为$pπ$和一个双轻子对 显示英文标题

标题： Polarized $Λ_b$ baryon decay to $pπ$ and a dilepton pair

摘要： 最近的$b\to s\ell^+\ell^-$转换中的异常可能源自标准模型之外的新物理。 为了确认或排除这一假设，需要对$b\to s\ell^+\ell^-$转换进行更多测试。 极化的$\Lambda_b$衰变到一个$\Lambda$和一个二轻子对提供了大量适合区分新物理与标准模型的可观测量。 在本文中，我们对极化的$\Lambda_b$衰变到一个$\Lambda(\to p\pi)\ell^+\ell^-$最终态进行了完整的角度分析。 研究是在一组算符中进行的，其中标准模型算符基被其手性反转的对应项以及新的标量和赝标量算符所补充。 通过保留最终态轻子的质量计算了完整的角度分布。 在低强子反冲情况下，我们使用重夸克有效理论框架来关联强子形式因子，从而得到角可观测量的简化表达式，其中短程和长程物理可以分离。 利用可观测量的分离表达式，我们构建了一系列短程和长程物理的测试，包括可以使用实验数据进行的标准模型及其手性反转对应项的零测试。 显示英文摘要

摘要： The recent anomalies in $b\to s\ell^+\ell^-$ transitions could originate from some New Physics beyond the Standard Model. Either to confirm or to rule out this assumption, more tests of $b\to s\ell^+\ell^-$ transition are needed. Polarized $\Lambda_b$ decay to a $\Lambda$ and a dilepton pair offers a plethora of observables that are suitable to discriminate New Physics from the Standard Model. In this paper, we present a full angular analysis of a polarized $\Lambda_b$ decay to a $\Lambda(\to p\pi)\ell^+\ell^-$ final state. The study is performed in a set of the operator where the Standard Model operator basis is supplemented with its chirality flipped counterparts, and new scalar and pseudo-scalar operators. The full angular distribution is calculated by retaining the mass of the final state leptons. At the low hadronic recoil, we use the Heavy Quark Effective Theory framework to relate the hadronic form factors which lead to simplified expression of the angular observables where short- and long-distance physics factorize. Using the factorized expressions of the observables, we construct a number of tests of short- and long-distance physics including null tests of the Standard Model and its chirality flipped counterparts that can be carried out using experimental data.