Supersymmetric Dark Matter and Lepton Flavor Violation

Abstract

The MSSM is often augmented by heavy singlets, in order to account for neutrino masses via the seesaw mechanism. However, these singlets can significantly impact predictions for neutralino relic density via RG effects on the SUSY mass spectrum and the concomitant changes to annihilation and detection rates. We study the interplay between these RG-mediated neutrino sector effects on relic density and constraints from lepton flavor violation, in CMSSM/mSUGRA-like models using several different GUT-inspired schemes for choosing neutrino sector parameters and mixings. We find that these effects can be very important for predictions of LFV rates; proper consideration of the changes to relic density bounds alters the predicted LFV rates by factors from a few up to two orders of magnitude, depending on the location in parameter space. Surprisingly, our results indicate that a large neutrino Yukawa unification parameter Rν u = 3 is not ruled out by current LFV bounds as was commonly thought. We also discuss our code Isajet-M, a modification and extension of standard Isajet, which we used to solve the RGEs. Isajet-M handles both the neutrino and quark sectors in complex matrix form, integrates out all particles at their individual scales, and calculates the sparticle spectrum, neutrino masses and mixings, rates for LFV processes, contributions to (g-2)μ, and neutralino relic density and cross-sections.