On the angular distribution of $\Lambda_b\to\Lambda(\to N\pi)\tau^+\tau^-$ decay

TL;DR

This paper provides a comprehensive analysis of the angular distribution in the decay process mbda_bmbda(N tau^+ au^-) considering massive leptons, including potential new physics effects, with detailed expressions and numerical evaluations.

Contribution

It offers the first full angular distribution including new physics operators and uses lattice QCD form factors for numerical analysis.

Findings

Angular coefficients are expressed in terms of transversity amplitudes.

Studied mbda_bmbda( p tau^+ au^-) observables in SM and beyond.

Numerical results based on lattice QCD form factors.

Abstract

We present a full angular distribution of the four body $\Lambda_b\to\Lambda(\to N\pi)\ell^+\ell^-$ decay where the leptons are massive and the $\Lambda_b$ is unpolarized, in an operator basis which includes the Standard Model operators, new vector and axial-vector operators, and scalar and pseudo-scalar operators. The angular coefficients are expressed in terms of transversity amplitudes. We study several $\Lambda_b\to\Lambda(\to p\pi)\tau^+\tau^-$ observables in the Standard Model and in the presence of the new operators. For our numerical analysis, we use the form factors from lattice QCD calculations.