Angular analysis of $\bar{B}\to D_2^*(\to D \pi)\ell \bar{\nu}$ decay and new physics

TL;DR

This paper derives a detailed angular distribution for the decay involving a tensor meson and explores how it can reveal new physics beyond the Standard Model, especially in light of anomalies in $b o c au ar{ u}$ transitions.

Contribution

It provides the first comprehensive angular analysis of $ar{B} o D_2^*( o D \pi)\, ext{l}ar{ u}$ decay including new physics operators and right-handed neutrinos.

Findings

Identifies multiple observables sensitive to new physics effects.

Analyzes the impact of various effective operators on decay distributions.

Offers a framework to test SM and new physics in future experiments.

Abstract

We derive the four-fold angular distribution for the semileptonic decay $\bar{B}\to D_2^*(\to D \pi)\,\ell \bar{\nu}$ where $D_2^*$(2460) is a tensor meson. We start with the most general beyond the Standard Model (SM) dimension-six effective Hamiltonian which comprises (axial)vector, (pseudo)scalar and tensor operators for both quark and lepton currents, and it also includes the right-handed neutrinos. The decay can be described by 16 transversity amplitudes and it provides a multitude of observables which can be extracted from data. We investigate the observables in the context of the SM and the new physics scenarios which can explain the intriguing discrepancies observed in the $b \to c \tau \bar{\nu}$ data.