# Determinations of $|V_{cb}|$ and $|V_{ub}|$ from baryonic $\Lambda_b$ decays

## TL;DR

This paper determines the CKM matrix elements |V_{cb}| and |V_{ub}| using baryonic Lambda_b decays, providing results consistent with inclusive B decay measurements and highlighting the potential of baryonic decays for CKM parameter extraction.

## Contribution

The study introduces a novel extraction of |V_{cb}| and |V_{ub}| from Lambda_b baryon decays, utilizing recent precise measurements of branching ratios that were not previously employed.

## Key findings

- |V_{cb}| = (44.0 ± 3.5)×10^{-3} consistent with inclusive B decays
- |V_{ub}| = (4.2 ± 0.4)×10^{-3} close to inclusive B decay values
- Results support the reliability of baryonic decays for CKM matrix element determination

## Abstract

We extract the Cabibbo-Kobayashi-Maskawa matrix element $V_{cb}$ from the exclusive decays of $\Lambda_b\to \Lambda_c\ell\bar \nu_\ell$ and $\Lambda_b\to \Lambda_c M_{(c)}$ with $M=(\pi^-,K^-)$ and $M_c=(D^-,D^-_s)$, where the branching ratios of $\Lambda_b\to \Lambda M_{(c)}$ measured with high precisions have not been used in the previous studies. Explicitly, we find $|V_{cb}|=(44.0\pm 3.5)\times 10^{-3}$, which agrees with the value of $(42.11\pm 0.74)\times 10^{-3}$ from the inclusive $B\to X_c\ell\bar \nu_\ell$ decays. Furthermore, based on the most recent ratio of $|V_{ub}|/|V_{cb}|$ from the exclusive $\Lambda_b$ decays, we obtain $|V_{ub}|=(4.2\pm 0.4)\times 10^{-3}$, which is close to the value of $(4.49\pm 0.24)\times 10^{-3}$ from the inclusive $B\to X_u\ell\bar \nu_\ell$ decays. We conclude that our determinations of $|V_{cb}|$ and $|V_{ub}|$ from the exclusive $\Lambda_b$ decays favor the inclusive extractions in the $B$ decays.