New GUT predictions for quark and lepton mass ratios confronted with phenomenology

TL;DR

This paper explores how GUT symmetry breaking predicts specific quark and lepton mass ratios at high energy scales, examining their viability under various SUSY scenarios and phenomenological constraints, and proposing new testable GUT predictions.

Contribution

It introduces new GUT scale mass ratio predictions considering SUSY threshold corrections and phenomenological constraints, expanding beyond traditional relations.

Findings

New GUT scale ratios like m_mu/m_s=9/2 or 6 are favored.

Certain GUT predictions are compatible with current phenomenological constraints.

Predictions are testable at CERN LHC and future colliders.

Abstract

Group theoretical factors from GUT symmetry breaking can lead to predictions for the ratios of quark and lepton masses (or Yukawa couplings) at the unification scale. Due to supersymmetric (SUSY) threshold corrections the viability of such predictions can depend strongly on the SUSY parameters. For three common minimal SUSY breaking scenarios with anomaly, gauge and gravity mediation we investigate which GUT scale ratios $m_e/m_d$, $m_\mu/m_s$, $y_\tau/y_b$ and $y_t/y_b$ are allowed when phenomenological constraints from electroweak precision observables, $B$ physics, $(g-2)_\mu$, mass-limits on sparticles from direct searches as well as, optionally, constraints from the observed dark matter density are taken into account. We derive possible new predictions for the GUT scale mass ratios and compare them with the phenomenologically allowed ranges. We find that new GUT scale predictions such as $m_\mu/m_s = 9/2$ or 6 and $y_\tau/y_b = 3/2$ or 2 are often favoured compared to the ubiquitous relations $m_\mu/m_s = 3$ or $y_\tau/y_b =1$. They are viable for characteristic SUSY scenarios, testable at the CERN LHC and future colliders.