Effects of vector leptoquarks on $ \Lambda_b \rightarrow \Lambda_c~\ell ~ \overline{\nu}_\ell$ decay

TL;DR

This paper investigates how a vector leptoquark could influence baryonic decay processes, specifically $\, ext{Lambda}_b ightarrow ext{Lambda}_c \, ext{lepton} \, ext{neutrino}$, and compares predictions with the Standard Model to identify potential new physics signals.

Contribution

It introduces the effects of a specific vector leptoquark on baryonic decay observables, extending leptoquark studies beyond mesonic anomalies.

Findings

Leptoquark significantly alters differential branching ratios.

Forward-backward asymmetry shows notable deviations from SM.

Lepton and baryon polarization predictions are affected by leptoquark presence.

Abstract

Experimental data on $ R(D^{(*)}) $, $ R(K^{(*)}) $ and $ R(J/\psi) $, provided by different collaborations, show sizable deviations from the SM predictions. To describe these anomalies many new physics scenarios have been proposed. One of them is leptoquark model with introducing the vector and scalar leptoquarks coupling simultaneously to the quarks and leptons. To look for similar possible anomalies in baryonic sector, we investigate the effects of a vector leptoquark $U_3 (3,3, \frac{2}{3})$ on various physical quantities related to the tree-level $ \Lambda_b \rightarrow \Lambda_c \ell ~ \overline{\nu}_\ell$ decays ($ \ell=\mu, ~\tau $), which proceed via $ b \rightarrow c~\ell ~ \overline{\nu}_\ell$ transitions at quark level. We calculate the differential branching ratio, forward-backward asymmetry and longitudinal polarizations of lepton and $\Lambda_{c}$ baryon at $ \mu $ and $ \tau $ lepton channels in leptoquark model and compare their behavior with respect to $ q^2 $ with the predictions of the standard model (SM). In the calculations we use the form factors calculated in full QCD as the main inputs and take into account all the errors coming from the form factors and model parameters. It is observed that ........