$ \Lambda_c $ semileptonic decays

TL;DR

This paper uses QCD sum rules to analyze the semileptonic decay of Lambda_c baryons into neutrons, providing theoretical predictions for decay rates and asymmetries relevant for understanding potential new physics.

Contribution

It presents the first analytical calculation of transition form factors for Lambda_c to neutron decays using QCD sum rules and z-series extrapolation, including decay asymmetries.

Findings

Branching fraction for Lambda_c to neutron e+ nu_e is approximately 0.28%.

Branching fraction for Lambda_c to neutron mu+ nu_mu is approximately 0.28%.

Decay asymmetries are computed and can probe new physics.

Abstract

Motivated by the recent experimental progress in the $ \Lambda_c $ decay that contains a neutron in the final state, we analyze the semileptonic decay $ \Lambda_c \rightarrow n \ell \nu_\ell $ in the framework of QCD sum rules. The transition form factors are analytically computed using three-point correlation functions and the Cutkosky cutting rules, which can be extrapolated into the physical region by employing the $ z $-series parametrization. The branching fractions of $ \Lambda_c \rightarrow n e^+ \nu_e $ and $ \Lambda_c \rightarrow n \mu^+ \nu_{\mu} $ are estimated to be $ (0.281\pm 0.056)\%$ and $ (0.275\pm 0.055)\% $, respectively. Furthermore, we calculate as well the relevant decay asymmetry observables sensitive to new physics beyond the standard model. The numerical results of semileptonic decays $ \Lambda_c \rightarrow \Lambda \ell \nu_\ell $ are also given and confronted to the latest experimental data.