论文标题
调查$ u_1 $ vector leptoquark对$ b \ touτ\barν$中介$ b $衰减的效果
Investigating the effect of $U_1$ vector leptoquark on $b\to u τ\barν$ mediated $B$ decays
论文作者
论文摘要
Lepton Flaim University（LFU）的最新测量结果违反了半乳房的$ b \ to c \ ell \barν$和$ b \ to s \ ell^+ \ ell^ - $ $ b \ $ b \ $ $ $ $ $ $（2-3）σ$偏离的过渡与相应的标准模型（SM）预测。这些诱人的信号暗示了新物理学（NP）在$ b \ tocτ\barν$和$ b \ tosμ^+μ^ - $ decay通道中的可能作用。反过来，这表明在$ b \至cτ\barν$中出现的同一类NP也可能出现在涉及$ b \ toUτ\barν$过渡的其他树级过程中。由于这些带电的当前过渡被双重抑制，因此NP的贡献可能足够重要，从而在某些可观察物中产生了很大的影响。在本文中，我们研究了矢量leptoquark $ u_1（3,1,2/3）$的含义，这是少数可以同时解释LFU违规的情况之一，同时在带电的电流中以及中性流动的群体中，在半蛋白质的衰老中，$ b \ bar $ $ b \ to（$ b \ f.） （k，k^*）τ\barν$。特别是，我们关注分支分数，Lepton风味非宇宙性（LNU）可观察到的前进不对称性和这些模式的极化不对称参数。由于$ U_1 $贡献，我们发现分支分数的实质性偏差以及这些衰减模式的LNU可观察到，这可以通过当前运行的实验LHCB和Belle-II进行探测。
The recent measurements of lepton flavor university (LFU) violating observables in semileptonic $b \to c \ell \barν $ and $b\to s\ell^+ \ell^-$ transitions by various experiments exhibit $(2-3)σ$ deviations from their corresponding Standard Model (SM) predictions. These tantalizing signals hint towards the possible role of new physics (NP) in $b \to c τ\barν$ and $b\to sμ^+μ^-$ decay channels. This in turn indicates that the same class of NP as appeared in $b \to c τ\barν$, might also show up in other tree level processes involving $b \to u τ\barν$ transition. Since these charged current transitions are doubly Cabibbo suppressed, the NP contributions could be significant enough leading to sizeable effects in some of the observables. In this paper, we study the implications of the vector leptoquark $U_1(3,1,2/3)$, which is one of the few scenarios that can simultaneously explain the LFU violation signals both in the charged-current as well as neutral-current sectors, on the semileptonic decays $B \to (π, ρ, ω)τ\barν$ and $B_s \to (K, K^*) τ\barν$. In particular, we pay our attention to the branching fraction, lepton flavor non-universality (LNU) observable, forward-backward asymmetry and the polarization asymmetry parameters of these modes. We find substantial deviations in the branching fractions as well as LNU observables of these decay modes due to the $U_1$ contributions, which can be probed by the currently running experiments LHCb and Belle-II.
