Probing effects of new physics in $\Lambda^0_{b}\to\Lambda^+_{c}\mu^{-}\bar{\nu}_{\mu}$ decays

TL;DR

This paper derives a detailed decay density expression for Lambda_b to Lambda_c mu nu decays, incorporating new physics operators and baryon polarization, and assesses experimental sensitivity to new physics effects at LHCb.

Contribution

It provides the first six-fold differential decay density formula including polarization and new physics operators, enabling precise sensitivity studies for new physics in Lambda_b decays.

Findings

Sensitivity to Wilson coefficients of new physics operators is evaluated.

Experimental precision on Lambda_b polarization and decay asymmetry is estimated.

Two decay scenarios are analyzed for their potential to detect new physics effects.

Abstract

We present, for the first time, the six-fold differential decay density expression for $\Lambda^0_b\to\Lambda^+_{c} l^- \bar{\nu}_{l}$, taking into account the polarisation of the $\Lambda^0_b$ baryon and a complete basis of new physics operators. Using the expected yield in the current dataset collected at the LHCb experiment, we present sensitivity studies to determine the experimental precision on the Wilson coefficients of the new physics operators with $\Lambda^0_{b}\to\Lambda^+_{c}\mu^{-}\bar{\nu}_{\mu}$ decays in two scenarios. In the first case, unpolarised $\Lambda^0_{b}\to\Lambda^+_{c}\mu^{-}\bar{\nu}_{\mu}$ decays with $\Lambda^+_c\to p K^+ \pi^-$ are considered, whereas polarised $\Lambda^0_{b}\to\Lambda^+_{c}\mu^{-}\bar{\nu}_{\mu}$ decays with $\Lambda^+_c \to p K^0_S$ are studied in the second. For the latter scenario, the experimental precision that can be achieved on the determination of $\Lambda^0_b$ polarisation and $\Lambda^+_c$ weak decay asymmetry parameter is also presented.