# CP asymmetry in the decays B -> X s, X d mu mu- with four generations - High Energy Physics - Phenomenology

CP asymmetry in the decays B -> X s, X d mu mu- with four generations - High Energy Physics - Phenomenology - Download this document for free, or read online. Document in PDF available to download.

Abstract: We estimate the CP asymmetry A {CP}q^2 in the decays B -> X s mu+ mu- andB -> X d mu+ mu- in the standard model SM with an additional fourthgeneration. We use a parametrization that allows us to explore the completeparameter space of the 4X4 quark mixing matrix, and constrain these parametersfrom the current data on B decays. We find that the enhancement in A {CP}q^2depends strongly on the mass of the t-, the up-type quark in the fourthgeneration. For m t- around 400 GeV, the CP asymmetry in the high-q^2 regionq^2 > 14.4 GeV^2 can be enhanced by more than an order of magnitude for B ->X s mu+ mu- and up to a factor of 6 for B -> X d mu+ mu-. There is noenhancement in the low-q^2 region 1< q^2 <6 GeV^2. With increasing m t-, theA {CP}q^2 in the high-q^2 low-q^2 region first decreases increases andthen saturates at a value a few times the SM prediction. In the high-q^2 regionof B -> X s mu+ mu-, this saturation value may be up to 25 times the SMexpectation.

Author: ** Ashutosh Kumar Alok, Amol Dighe, Shamayita Ray**

Source: https://arxiv.org/