Quark and lepton masses at the GUT scale including SUSY threshold corrections

TL;DR

This paper examines how supersymmetric threshold corrections influence the values of quark and lepton masses at the GUT scale, highlighting their impact on GUT model building in the large tan beta MSSM regime.

Contribution

It provides a detailed analysis of SUSY threshold effects, including electroweak contributions, on fermion mass ratios at the GUT scale, expanding the parameter space for GUT models.

Findings

SUSY threshold corrections significantly alter GUT scale Yukawa couplings.

Electroweak contributions are important alongside SUSY QCD effects.

Enlarged parameter ranges may enable new GUT model constructions.

Abstract

We investigate the effect of supersymmetric (SUSY) threshold corrections on the values of the running quark and charged lepton masses at the GUT scale within the large $\tan\beta$ regime of the MSSM. In addition to the typically dominant SUSY QCD contributions for the quarks, we also include the electroweak contributions for quarks and leptons and show that they can have significant effects. We provide the GUT scale ranges of quark and charged lepton Yukawa couplings as well as of the ratios $m_\mu/m_s$, $m_e/m_d$, $y_\tau/y_b$ and $y_t/y_b$ for three example ranges of SUSY parameters. We discuss how the enlarged ranges due to threshold effects might open up new possibilities for constructing GUT models of fermion masses and mixings.