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

TL;DR

This paper measures the absolute branching fraction of the inclusive semileptonic decay of the bc^+ baryon using BESIII data, providing key insights into charm baryon semileptonic decays and their comparison to meson decays.

Contribution

It presents the first precise measurement of the inclusive semileptonic branching fraction of bc^+ and compares its decay width to nonstrange charmed mesons.

Findings

Branching fraction bc^+ 7e = (3.95 b1 0.34 b1 0.09)%

Decay width ratio bc^+ to D mesons = 1.26 b1 0.12

Provides data for testing charm baryon decay models

Abstract

Using a data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ collected at a center-of-mass energy of $\sqrt{s}=4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic $\Lambda_c^+$ decay with a double-tag method. We obtain $\mathcal{B}(\Lambda_c^+ \rightarrow X e^+ \nu_e) = (3.95\pm0.34\pm0.09)\%$, where the first uncertainty is statistical and the second systematic. Using the known $\Lambda_c^+$ lifetime and the charge-averaged semileptonic decay width of nonstrange charmed measons ($D^0$ and $D^+$), we obtain the ratio of the inclusive semileptonic decay widths $\Gamma(\Lambda_c^+ \rightarrow X e^+ \nu_e)/\bar{\Gamma}(D\rightarrow X e^+ \nu_e)= 1.26\pm0.12$.