Improved measurement of the absolute branching fraction of inclusive semileptonic $\Lambda_c^+$ decay

TL;DR

This paper reports a more precise measurement of the absolute branching fraction of the inclusive semileptonic decay of the Lambda_c+ baryon using BESIII data, significantly improving previous results and providing insights into decay width ratios.

Contribution

The study provides the most precise measurement to date of the Lambda_c+ inclusive semileptonic branching fraction and the ratio of its decay width to that of nonstrange charmed mesons.

Findings

Branching fraction measured as (4.06 ± 0.10 ± 0.09)%

Decay width ratio of Lambda_c+ to D mesons is 1.28 ± 0.05

Measurement precision is over three times better than previous results

Abstract

Using $4.5 \mathrm{fb}^{-1}$ of $e^+e^-$ annihilation data samples collected at center-of-mass energies ranging from 4.600 to 4.698 GeV with the BESIII detector at the BEPCII collider, we measured the absolute branching fraction for the inclusive semileptonic decay $\Lambda_c^+\rightarrow Xe^+\nu_e$, where $X$ refers to any possible particle system. The branching fraction of the decay is determined to be $\mathcal{B}({\it \Lambda}^+_c\rightarrow Xe^+\nu_e)=(4.06\pm0.10_{\rm stat.}\pm0.09_{\rm syst.})\%$. Our result improves the precision of previous measurement of $\mathcal{B}({\it \Lambda}^+_c\rightarrow Xe^+\nu_e)$ by more than threefold. Using the known $\Lambda_c^+$ lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons, we measure the ratio of inclusive semileptonic decay widths $\Gamma(\Lambda_c^+\rightarrow X e^+\nu_e)/\bar{\Gamma}(D\rightarrow Xe^+\nu_e)=1.28\pm0.05$, where statistical and systematic uncertainties are combined.