New physics signature in D^0 (bar{D}^0)rightarrow f effective width asymmetries

Abstract

Violation of charge conjugation-parity (mathrm CP) symmetry plays a major rule in the dominance of matter in our universe. A kind of mathrm CP violation results from the asymmetry of the life time measured in M^0 and {bar{M}}^0, here M is a heavy meson, decays to final states which is referred in the literature as A_{Gamma }^f. In this paper, we give an estimation of the upper bound on |A_{Gamma }^f| for the Cabibbo Favored D^0 rightarrow K^- pi ^+ decay process in different models. We show that in the standard model, |A_{Gamma }^f| lesssim {mathcal {O}} (10^{-10}). Recently a bound on A_{Gamma }^f has been obtained: (A^f_{Gamma })^{Exp.}= (1.6 pm 1)times 10^{-4}. This result motivates further studies on A_{Gamma }^f in beyond standard model physics. In the framework of two Higgs doublet model with generic Yukawa structure, we show that |A_Gamma ^{f}|lesssim {mathcal {O}} (10^{-7}) which is several orders of magnitude smaller than the current experimental value. Finally, in the framework of left-right symmetric models in which the mixing between the left and the right gauge bosons is allowed and the left-right symmetry is not manifest at unification scale, we find that A_{Gamma }^f can be as large as |A_{Gamma }^f|lesssim {mathcal {O}} (10^{-5}) which is one order of magnitude smaller than the experimentally measured value by LHCb collaborators.