An effective look at right-handed currents and quark flavour mixing

TL;DR

This paper develops an effective theory for left-right symmetric models with right-handed currents, addressing the |V_{ub}| problem and analyzing their impact on flavour mixing, rare decays, and phenomenological constraints.

Contribution

It introduces a method to determine the right-handed mixing matrix within a left-right symmetric framework using theoretical and experimental data.

Findings

Right-handed currents can resolve the |V_{ub}| problem.

The right-handed mixing matrix is constrained by flavour observables.

Predictions for rare decay processes are discussed.

Abstract

We present an effective theory approach for a model with a left-right symmetric flavour group broken only by the Yukawa couplings. An underlying SU(2)_L x SU(2)_R x U(1)_{B-L} global symmetry is assumed without specifying the fundamental theory. The model is motivated by the fact that the |V_{ub}| problem can be solved by assuming the existence of right-handed (RH) currents. In this framework the flavour mixing in the RH sector is given by a new mixing matrix. After a short introduction of the model, we show how this RH mixing matrix can be determined by theory, experimental data and phenomenological constraints. We summarize the results of the RH contribution to flavour mixing in Delta F=2 processes. Furthermore we briefly discuss Z -> b bbar and the rare decays B_{s,d} -> mu+ mu-, B -> {X_s,K,K*} nu nubar and K -> pi nu nubar with corresponding correlations.