Anatomy and Phenomenology of the Lepton Flavor Universality in SUSY Theories

TL;DR

This paper investigates how high-precision electroweak tests, especially lepton flavor universality breaking in kaon decays, can constrain supersymmetric theories and reveal potential new physics beyond the Standard Model.

Contribution

It demonstrates the effectiveness of kaon decay measurements in constraining SUSY models and lepton flavor violation, highlighting their importance alongside LHC searches.

Findings

Kaon decay tests strongly constrain SUSY parameter space.

Lepton flavor universality violation in kaon decays probes lepton flavor violation.

Complementarity between indirect LFU tests and direct LHC searches.

Abstract

High precision electroweak tests, such as deviations from the Standard Model expectations of the Lepton Flavor Universality breaking in K->lnu (with l= e or mu), represent a powerful tool to test the Standard Model and, hence, to constrain or obtain indirect hints of New Physics beyond it. We explore such a possibility within Supersymmetric theories. Interestingly enough, a process that in itself does not need lepton flavor violation to occur, i.e. the violation of mu-e non-universality in K_l2, proves to be quite effective in constraining not only relevant regions of SUSY models where lepton flavor is conserved, but even those where specific lepton flavor violating contributions arise. Indeed, a comparison with analogous bounds coming from tau lepton flavor violating decays shows the relevance of the measurement of R_K to probe Lepton Flavor Violation in SUSY. We outline the role and the interplay of the direct New Physics searches at the LHC with the indirect searches performed by LFU tests.