Disentangling left-handed and right-handed neutrino effects in $B_c \to τ\barν_τ$ decay

Fuente: arXiv
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Main Author: Hu, Quan-Yi
Format: Preprint
Published: 2024
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author Hu, Quan-Yi
author_facet Hu, Quan-Yi
contents Inspired by the anomalies in $B\to D^{(*)} τ\barν_τ$ decay, in this work, we carefully study the influence of the most general dimension-six effective operators involving right-handed neutrinos on the four cascade decays $B_c \to τ(\to ν_τh ) \barν_τ$ ($h=π,ρ$) and $B_c \to τ(\to ν_τ\ell \barν_\ell) \barν_τ$ ($\ell =μ, e$). We calculate for the first time the analytical results of the distributions of the differential decay rates of these cascade decays with respect to the energy of the charged particles in the final state. We select a total of 13 new physics benchmark points, among which 9 are derived from the effect of purely left-handed neutrinos, and the other 4 are from the effect of purely right-handed neutrinos. We find that the benchmark points BP4, BP6, BP11, and BP13 can significantly increase the values of these distributions while the BP3 causes a sharp decrease in these distributions. The end-point behavior of the differential distribution $dΓ/dE_π$ can be used to disentangle the effects of left-handed and right-handed neutrinos. Finally, in order to eliminate the uncertainties brought by the CKM matrix element $V_{cb}$ and the decay constant $f_{B_c}$, we introduce the normalized distributions $dΓ/(ΓdE_a)$ ($a=π,ρ,μ,e$), which are only sensitive to the right-handed neutrinos. We find that in each normalized distribution there exists a fixed point that is not related to any dimension-six effective operators considered in this work.
format Preprint
id arxiv_https___arxiv_org_abs_2407_19550
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Disentangling left-handed and right-handed neutrino effects in $B_c \to τ\barν_τ$ decay
Hu, Quan-Yi
High Energy Physics - Phenomenology
Inspired by the anomalies in $B\to D^{(*)} τ\barν_τ$ decay, in this work, we carefully study the influence of the most general dimension-six effective operators involving right-handed neutrinos on the four cascade decays $B_c \to τ(\to ν_τh ) \barν_τ$ ($h=π,ρ$) and $B_c \to τ(\to ν_τ\ell \barν_\ell) \barν_τ$ ($\ell =μ, e$). We calculate for the first time the analytical results of the distributions of the differential decay rates of these cascade decays with respect to the energy of the charged particles in the final state. We select a total of 13 new physics benchmark points, among which 9 are derived from the effect of purely left-handed neutrinos, and the other 4 are from the effect of purely right-handed neutrinos. We find that the benchmark points BP4, BP6, BP11, and BP13 can significantly increase the values of these distributions while the BP3 causes a sharp decrease in these distributions. The end-point behavior of the differential distribution $dΓ/dE_π$ can be used to disentangle the effects of left-handed and right-handed neutrinos. Finally, in order to eliminate the uncertainties brought by the CKM matrix element $V_{cb}$ and the decay constant $f_{B_c}$, we introduce the normalized distributions $dΓ/(ΓdE_a)$ ($a=π,ρ,μ,e$), which are only sensitive to the right-handed neutrinos. We find that in each normalized distribution there exists a fixed point that is not related to any dimension-six effective operators considered in this work.
title Disentangling left-handed and right-handed neutrino effects in $B_c \to τ\barν_τ$ decay
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2407.19550