B Decays in an Asymmetric Left-Right Model

Abstract

Motivated by recently observed disagreements with the SM predictions in $B$ decays, we study $b\to d,s$ transitions in an asymmetric class of $SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$ models, with a simple one-parameter structure of the right handed mixing matrix for the quarks, which obeys the constraints from kaon physics. We use experimental constraints on the branching ratios of $b\to s\gamma$, $b\to ce{\bar{\nu }}_e$, and $B_{d,s}^0-{\bar{B}}_{d,s}^0$ mixing to restrict the parameters of the model: $g_R/g_L,M_{W_2},M_{H^{\pm }},\tan \beta$ as well as the elements of the right-handed quark mixing matrix $V_{CKM}^R$. We present a comparison with the more commonly used (manifest) left-right symmetric model. Our analysis exposes the parameters most sensitive to $b$ transitions and reveals a large parameter space where left- and right-handed quarks mix differently, opening the possibility of observing marked differences in behaviour between the standard model and the left-right model.

Comments: 32 pages and 8 figures