论文标题
带电粒子的可见能量和角度分布从$τ-$ b \ in $ b \ tocτ\，（μ\barν_μν_τ，πν_τ，ρν_τ）\barν_τ$反应
Visible energy and angular distributions of the charged particle from the $τ-$decay in $b\to c τ\, (μ\bar ν_μν_τ,πν_τ,ρν_τ) \barν_τ$ reactions
论文作者
论文摘要
我们研究$ d^2γ_d /（dΩd\cosθ_d）$，$dγ_d /d \cosθ_d$和$dγ_d /de_d $ distributions，这些定义是根据$ b \ b \ b \ c f \ c f \ c f \ c f \ c f f the $τ-decay的可见能量和极性角度定义的（ ν_μν_τ，πν_τ，ρν_τ）\barν_τ$ reactions。前两个包含有关$ h_b \ \h_cτ\barν_τ$父母衰减的横向tau旋转，tau角和tau角 - 旋转不对称的信息，并且从动态的角度来看，它们比常用的一个，$ d^2γ_d /domliative of taue the tau tau tau tau tau tau tau taue taue tau taue ta taue ta ta taue tau taue langest taue ta ta ta tau taud tau taud taue taue ta tauc land ta taud ta ta ta taud。考虑到有效的现场理论方法，我们考虑了这些新物理（NP）操作员在有效的现场理论方法中使用右中微子和左中微子领域构建的新物理（NP）操作员，请注意这些新观测值的标准模型（SM）的预测。我们提出了$λ_B\toλ_cτ\，（μ\barν_μν_τ，πν_τ，ρν_τ）\barν_τ$和$ \ bar b \ to d^{（*）}τ\，不同的NP模型之间的分离。在这方面，我们表明$dγ_d /d \cosθ_d$应以足够好的统计数据进行测量，变得非常有用，尤其是在$τ\至πν_τ$模式下。这项工作中进行的研究可能具有特殊的相关性，这是由于LHCB测量了Lepton风味通用性比率$ {\ cal r} _ {λ_c} $与SM一致。该实验使用其强子衰减识别为$π^-π^+π^-ν_τ$，并且对于$ {\ cal r} _ {λ_c} $，该结果与$ b $ - 米斯托部门的现象学冲突，需要从其他Tau Reponstruction Channels确认。
We study the $d^2 Γ_d /(dωd\cosθ_d) $, $dΓ_d /d\cosθ_d$ and $ dΓ_d /dE_d $ distributions, which are defined in terms of the visible energy and polar angle of the charged particle from the $τ-$decay in $b\to c τ\, (μ\bar ν_μν_τ,πν_τ,ρν_τ) \barν_τ$ reactions. The first two contain information on the transverse tau-spin, tau-angular and tau-angular-spin asymmetries of the $H_b\to H_cτ\barν_τ$ parent decay and, from a dynamical point of view, they are richer than the commonly used one, $d^2 Γ_d /(dωdE_d) $, since the latter only depends on the tau longitudinal polarization. We pay attention to the deviations with respect to the predictions of the standard model (SM) for these new observables, considering new physics (NP) operators constructed using both right- and left-handed neutrino fields, within an effective field-theory approach. We present results for $Λ_b\toΛ_cτ\, (μ\bar ν_μν_τ,πν_τ,ρν_τ)\barν_τ$ and $\bar B \to D^{(*)}τ\, (μ\bar ν_μν_τ,πν_τ,ρν_τ) \barν_τ$ sequential decays and discuss their use to disentangle between different NP models. In this respect, we show that $dΓ_d /d\cosθ_d$, which should be measured with sufficiently good statistics, becomes quite useful, especially in the $τ\to πν_τ$ mode. The study carried out in this work could be of special relevance due to the recent LHCb measurement of the lepton flavor universality ratio ${\cal R}_{Λ_c}$ in agreement with the SM. The experiment identified the $τ$ using its hadron decay into $π^-π^+π^-ν_τ$, and this result for ${\cal R}_{Λ_c}$, which is in conflict with the phenomenology from the $b$-meson sector, needs confirmation from other tau reconstruction channels.
