Impact of a non-universal $Z^{\prime }$ on the $B\to K^{(\ast )}{l}^{+}{l}^{-}$ and $B\to K^{(\ast )}\nu \bar{\nu }$ processes

Abstract

We perform a study of the new physics effects in semileptonic FCNC processes within a low-energy approximation of the anomaly-free supersymmetic extension of the SM with additional $Z^{\prime }$ vector field. The key feature of the model is the non-diagonal structure of $Z^{\prime }$ couplings to fermions, which is parameterized by few new-physics parameters in addition to well-known mixing matrices for quarks and leptons in the SM. We not only consider CP-conserving scenarios with real parameters, but also account for possible CP violation due to new physical weak phases. We analyse the dependence of the $b\to s$ observables on the parameters together with correlations between the observables predicted in the model. Special attention is paid to possible enhancement of $B\to K^{(\ast )}\nu \bar{\nu }$ rates and to CP-odd angular observables in $B\to K^{\ast }ll$ decays.

Comments: 14 pages, 4 figures, references updated. arXiv admin note: text overlap with arXiv:2207.10613 by other authors