论文标题
探索新物理学在$ b \ touτ\barν$衰减中的作用
Exploring the role of new physics in $b \to u τ\bar ν$ decays
论文作者
论文摘要
最近对三个开创性实验的$ r_d $，$ r_d $，$ r_ {d^*} $和$ r_ {j/ψ} $的测量值，Babar，Belle和LHCB，表明Lepton风味普遍性的概念在薄弱的充电过程中违反了通过$ b \ by c \ ell \ ell \ ell \ ell \ ell \ el fly the the Charged-Crurnent流程。这些有趣的结果在$（2-3）σ$的水平上描述了其标准模型预测的张力，最近触发了许多新的物理命题，并且通常归因于$ b \ to b \ to cτ\ barν$转变的新物理学可能含义。反过来，这又开辟了另一个途径，即$ b \ touτ\barν$过程，以寻找新的物理。由于这些过程受到双重抑制，因此新物理学的影响可能足够重要，从而在某些可观察物中产生了很大的影响。在这项工作中，我们详细研究了新物理学在$ b \ to（π，ρ，ω）τ\barν$和$ b_s \ to（k，k^*）τ\barν$过程中考虑模型独立方法的过程。特别是，我们专注于标准可观察物，例如分支分数，Lepton风味非宇宙性（LNU）参数，前后不对称和极化不对称。我们发现其中一些可观察到的偏差很大，可以通过当前运行的实验LHCB和Belle-II探索。我们还简要评论了标量leptoquark $ r_2（3,2,7/6）$和vector leptoquark $ u_1（3,1,2/3）$对这些衰减模式的影响。
The recent measurements on $R_D$, $R_{D^*}$ and $R_{J/ψ}$ by three pioneering experiments, BaBar, Belle and LHCb, indicate that the notion of lepton flavour universality is violated in the weak charged-current processes, mediated through $b \to c \ell \bar ν_\ell$ transitions. These intriguing results, which delineate a tension with their standard model predictions at the level of $(2-3)σ$ have triggered many new physics propositions in recent times, and are generally attributed to the possible implication of new physics in $ b \to c τ\bar ν$ transition. This, in turn, opens up another avenue, i.e., $ b \to u τ\bar ν$ processes, to look for new physics. Since these processes are doubly Cabibbo suppressed, the impact of new physics could be significant enough, leading to sizeable effects in some of the observables. In this work, we investigate in detail the role of new physics in $B \to (π,ρ,ω)τ\bar ν$ and $B_s \to (K,K^*) τ\bar ν$ processes considering a model independent approach. In particular, we focus on the standard observables like branching fraction, lepton flavour non-universality (LNU) parameter, forward-backward asymmetry and polarization asymmetries. We find significant deviations in some of these observables, which can be explored by the currently running experiments LHCb and Belle-II. We also briefly comment on the impact of scalar leptoquark $R_2(3,2,7/6)$ and vector leptoquark $U_1(3,1,2/3)$ on these decay modes.
