Profiles of the Unitarity Triangle and CP-Violating Phases in the Standard Model and Supersymmetric Theories

TL;DR

This paper compares the CKM unitarity triangle and CP asymmetries in B decays within the Standard Model and supersymmetric models, highlighting similarities and potential differences in CP-violating phases that future experiments could detect.

Contribution

It provides a comparative analysis of CP-violating phases in the Standard Model and MSSM, incorporating next-to-leading-order corrections and current experimental constraints.

Findings

Predicted  ranges of  in SM and MSSM are very similar.

Precise measurements could distinguish models based on  and  phases.

Supersymmetric contributions to mass differences are approximately equal in the studied theories.

Abstract

We report on a comparative study of the profile of the CKM unitarity triangle, and the resulting CP asymmetries in B decays, in the standard model and in several variants of the minimal supersymmetric standard model (MSSM), characterized by a single phase in the quark flavour mixing matrix. The supersymmetric contributions to the mass differences \Delta M_d, \Delta M_s and to the CP-violating quantity |\epsilon| are, to an excellent approximation, equal to each other in these theories, allowing for a particularly simple way of implementing the resulting constraints on the elements of V_{CKM} from the present knowledge of these quantities. Incorporating the next-to-leading-order corrections and applying the current direct and indirect constraints on the supersymmetric parameters, we find that the predicted ranges of \sin 2 \beta in the standard model and in MSSM models are very similar. However, precise measurements at B-factories and hadron machines may be able to distinguish these theories in terms of the other two CP-violating phases \alpha and \gamma. This is illustrated for some representative values of the supersymmetric contributions in \Delta M_d, \Delta M_s and |\epsilon|.