Limits on New Physics from exclusive $B \to D^{(*)}\ell \bar\nu$ Decays

TL;DR

This paper investigates how non-standard interactions in $B o D^{(*)}\, ext{l}ar{ u}$ decays affect observables, providing constraints on new physics contributions beyond the Standard Model using recent data and form factor calculations.

Contribution

It extends the Standard Model hadronic current to include right-handed, scalar, and tensor contributions and analyzes their effects on decay observables with perturbative corrections.

Findings

Constraints on wrong helicity admixtures established

Limits on non-$V-A$ structures derived from data

Perturbative corrections up to order $oldsymbol{ ext{alpha}_s}$ included

Abstract

We consider the exclusive decays $B \to D^{(*)}\,\ell \bar\nu$ and study the effect of non $V-A$ structures on the observables. We extend the standard model hadronic current by additional right-handed vector as well as left- and right-handed scalar and tensor contributions and calculate the decay rates including the perturbative corrections up to order $\alpha_s$. Using the data of the exclusive semileptonic $b \to c $ decays and recent calculations of the form factors at the non-recoil point we discuss the constraints to the wrong helicity admixtures in the hadronic current.