论文标题
$ b \ tocτ\barν_{e，μ} $贡献$ r（d^{（*）}）$
$b\to cτ\barν_{e,μ}$ contributions to $R(D^{(*)})$
论文作者
论文摘要
$ r（d^{（*）}）$拼图代表$ \sim3σ$违反$ b \ to d^{（*）}τν$和$ b \ to d^{（*）} {（*）} \ ell的衰减率之间的Lepton风味普遍性。如果新物理学对其进行解释，则一般没有理由将相关的中微子分别分别为$ν_τ$和$ν_\ ell $。我们研究$τ$相关的速率是否可以通过对标准模型有效场理论（SMEFT）中一类运算符的D^{（*）}τν_\ ell $的重要贡献来提高。我们发现，被禁止或稀有的介子腐烂的上限意味着，违反Lepton风味的过程的贡献不超过所需偏移的$ 4 \％$。但是，新物理学不需要微调的风味对齐。搜索相关的高$ P_T $ PROCESS $ PP \toτ^\pmμ^\ mp $目前可以在Lepton风味的规模上放置一个违反新物理学的比例，该物理学的损失比来自中森衰减的限制弱$ 2.2 $。我们结论的例外是标量和张量SMEFT操作员的特定组合。
The $R(D^{(*)})$ puzzle stands for a $\sim3σ$ violation of lepton flavor universality between the decay rates of $B\to D^{(*)}τν$ and $B\to D^{(*)}\ellν$, where $\ell=e,μ$. If it is accounted for by new physics, there is no reason in general that the relevant neutrinos are, respectively, $ν_τ$ and $ν_\ell$. We study whether the $τ$ related rate could be enhanced by significant contributions to $B\to D^{(*)}τν_\ell$ from a class of operators in the Standard Model Effective Field Theory (SMEFT). We find the upper bounds from forbidden or rare meson decays imply that the contributions from the lepton flavor violating processes account for no more than about $4\%$ of the required shift. Yet, no fine-tuned flavor alignment is required for the new physics. Searching for the related high-$p_T$ process $pp\toτ^\pmμ^\mp$ can at present put a lower bound on the scale of the lepton flavor violating new physics that is a factor of $2.2$ weaker than the bound from meson decays. An exception to our conclusion arises from a specific combination of scalar and tensor SMEFT operators.
