New Physics effects in leptonic and semileptonic decays

TL;DR

This paper explores how current leptonic and semileptonic meson decay data can constrain new physics models by analyzing various decay modes and proposing new angular observables sensitive to beyond Standard Model effects.

Contribution

It introduces a comprehensive framework including scalar and tensor operators for analyzing decay data and suggests new angular observables for detecting new physics.

Findings

Constraints on new physics couplings derived from decay data

Identification of observables sensitive to beyond Standard Model effects

Use of lattice QCD results for accurate hadronic matrix elements

Abstract

We discuss the possibilities of extracting the constraints on New Physics by using the current data on the leptonic and semileptonic decays of pseudoscalar mesons. In doing so we use a general low energy Lagrangian that besides the vector and axial operators also includes the (pseudo-)scalar and tensor ones. In obtaining constraints on New Physics couplings we combine the experimental information concerning several decay modes with the accurate lattice QCD results for the hadronic matrix elements. We propose to study new observables that can be extracted from the angular analysis of the semileptonic decays and discuss their values both in the Standard Model and in some specific scenarios of physics beyond the Standard Model.