论文标题
$ \ bar b_c \ toη_c$，$ \ bar b_c \ to j/ψ$和$ \ bar b \ to d^{（*）} $ semileptonic衰减，包括新物理学
$\bar B_c \to η_c$, $\bar B_c \to J/ψ$ and $\bar B \to D^{(*)}$ semileptonic decays including new physics
论文作者
论文摘要
我们应用了N. n. n. n. n. [物理。 Rev. D 101，113004（2020）]到包含$ b $ quark的伪cal膜的半衰减。虽然目前的$ b \ d^{（*）} $数据提供了最有力的证据支持Lepton风味普遍性，但通常认为的观察物无法区分不同的新物理（NP）方案。在上面的参考文献中，我们讨论了对双差衰变宽度的各种贡献$ d^2γ/（dΩd\cosθ_\ ell）$和$ d^2γ/（dΩde_\ ell）$的各种贡献。在这里，$ω$是两个强子四速度的产物，$θ_\ ell $是最终Lepton和最终的强子三摩Momenta在最终的两级仪式中心的角度，而$ e_ \ ell $是实验室系统中的最终充电Lepton Energy。形式主义在此应用于$λ_b\toλ_c$ emeptonic衰变的分析，显示新的观测值能够分解不同的NP场景。在这里，我们将$ \ bar b_c \分析为η_cτ\barν_τ$，$ \ bar b_c \ b b_c \ j/ψτ\barν_τ$，$ \ bar b \ todτ\barν_τ$和$ \ bar b \ bar b \ to d^*d^*t^*t^*f^*τ\barν_τ$ semileptonic decays decays decays decays decays。我们表明，作为一般规则，即使包括$τ$极化，$ \ bar b_c \ to J/ψ$可观察到的东西也比从$ \ bar b_c \ toη_c$ decays或N. ponsunva等人提供的$ \ bar b_c \ to bar b_c \ to bar b_c \ to bar b_c \ tos bar b_c \ tos bar b_c \ bar b_c \ toss np方案更为最佳。对于相关的$λ_b\toλ_c$ emeptonic衰减。最后，我们证明$ \ bar b \ to d $和$ \ bar b_c \ toη_c$，以及$ \ bar b \ to d^*$和$ \ bar b_c \ to j/ψ$ decay observables表现出相似的行为。
We apply the general formalism derived in N. Penalva et al. [Phys. Rev. D 101, 113004 (2020)] to the semileptonic decay of pseudoscalar mesons containing a $b$ quark. While present $B\to D^{(*)}$ data give the strongest evidence in favor of lepton flavor universality violation, the observables that are normally considered are not able to distinguish between different new physics (NP) scenarios. In the above reference we discussed the relevant role that the various contributions to the double differential decay widths $d^2Γ/(dωd\cosθ_\ell)$ and $d^2Γ/(dωdE_\ell)$ could play to this end. Here $ω$ is the product of the two hadron four-velocities, $θ_\ell$ is the angle made by the final lepton and final hadron three-momenta in the center of mass of the final two-lepton system, and $E_\ell$ is the final charged lepton energy in the laboratory system. The formalism was applied there to the analysis of the $Λ_b\toΛ_c$ semileptonic decay showing the new observables were able to tell apart different NP scenarios. Here we analyze the $\bar B_c\to η_c τ\barν_τ$, $\bar B_c\to J/ψτ\barν_τ$, $\bar B\to Dτ\barν_τ$ and $\bar B\to D^*τ\barν_τ$ semileptonic decays. We show that, as a general rule, the $\bar B_c \to J/ψ$ observables, even including $τ$ polarization, are less optimal for distinguishing between NP scenarios than those obtained from $\bar B_c \to η_c$ decays, or those presented in N. Penalva et al. for the related $Λ_b \to Λ_c$ semileptonic decay. Finally, we show that $\bar B\to D$ and $\bar B_c\to η_c$, and $\bar B\to D^*$ and $\bar B_c\to J/ψ$ decay observables exhibit similar behaviors.
