Determination of $|V_{ub}|$ from exclusive baryonic $B$ decays

TL;DR

This paper determines the CKM matrix element |V_{ub}| using exclusive baryonic B decays, providing an independent measurement that aligns with existing results and aids in understanding the CKM matrix and potential new physics.

Contribution

It introduces a novel method to extract |V_{ub}| from baryonic B decays, independent of previous approaches, and provides a new value consistent with other measurements.

Findings

Measured |V_{ub}| as (3.48^{+0.87}_{-0.63} ext{(stat)} ext{+ systematic}) imes 10^{-3}

Results overlap with inclusive decay measurements, supporting current CKM matrix understanding

Highlights the usefulness of baryonic B decays in CKM element determination

Abstract

We use the exclusive baryonic $B$ decays to determine the Cabibbo-Kobayashi-Maskawa (CKM) matrix element $V_{ub}$. From the relation $|V_{ub}|^2/|V_{cb}|^2=({\cal B}_\pi/{\cal B}_D){\cal R}_{ff}$ based on $B^-\to p\bar p \pi^-$ and $\bar B^0\to p\bar p D^0$ decays, where $|V_{cb}|$ and ${\cal B}_\pi/{\cal B}_D\equiv{\cal B}(B^-\to p\bar p \pi^-)/{\cal B}(\bar B^0\to p\bar p D^0)$ are the data input parameters, while ${\cal R}_{ff}$ is the one fixed by the $B\to p\bar p$ transition matrix elements, we find $|V_{ub}|=(3.48^{+0.87}_{-0.63}\pm 0.40\pm 0.07)\times 10^{-3}$ with the errors corresponding to the uncertainties from ${\cal R}_{ff}$, ${\cal B}_\pi/{\cal B}_D$ and $|V_{cb}|$, respectively. Being independent of the previous results, our determination of $|V_{ub}|$ has the central value close to those from the exclusive $\bar B\to \pi\ell\bar \nu_\ell$ and $\Lambda_b\to p\mu^-\bar \nu_\mu$ decays, but overlaps the one from the inclusive $\bar B\to X_u \ell\bar \nu_\ell$ with the current uncertainties. The extraction of $|V_{ub}|$ in the baryonic $B$ decays is clearly very useful for the complete determination of the CKM matrix elements as well as the exploration of new physics.