Angular and CP-Violation Analyses of B - → D ⁎ + l - ν - l Decays at Hadron Collider Experiments

Abstract EN

The B - → D ⁎ + l - ν - l branching fractions ratio between muon and tau lepton decay modes R ( D ⁎ ) has shown intriguing discrepancies between the Standard Model prediction and measurements performed at BaBar, Belle, and LHCb experiments, a possible sign of beyond the Standard Model physics.

Theoretical studies show how observables related to the B - → D ⁎ + l - ν - l differential decay distribution can be used to further constrain New Physics contributions, but their experimental measurements are lacking to date.

This article proposes the measurement of B - → D ⁎ + l - ν - l angular and C P -violating observables at hadron collider experiments, by exploiting approximate reconstruction algorithms using information from detectable final-state particles only.

The resolution on the phase space variables is studied using B - → D ⁎ + l - ν - l decays simulated in a forward detector geometry like LHCb.

A method to correct the observable values for the reconstruction inaccuracies based on detector simulation is successfully tested on simulated data and the decrease in precision with respect to a perfect reconstruction is evaluated.

The D ⁎ + longitudinal polarization fraction and the A T ( 2 ) C P -violating observable can be measured losing a factor of 2 and 5 in precision, respectively.

The extraction of angular distributions from the template fit selecting B - → D ⁎ + l - ν - l decays and associated systematic uncertainties are also discussed.