New constraint on the minimal SUSY GUT model from proton decay

TL;DR

This paper reanalyzes proton decay in the minimal SUSY GUT model, revealing stronger constraints on model parameters due to the inclusion of previously neglected Higgsino dressing diagrams, leading to the exclusion of certain parameter ranges.

Contribution

It introduces the consideration of Higgsino dressing diagrams with right-handed matter fields in proton decay analysis, significantly tightening constraints on the minimal SUSY GUT model.

Findings

Stronger lower bounds on the colored Higgs mass $M_C$.

Exclusion of minimal models with sfermion mass $m_{ ilde{f}} \\lesssim 2$ TeV.

Proton decay constraints become more stringent with new diagram contributions.

Abstract

We present results of reanalysis on proton decay in the minimal SU(5) SUSY GUT model. Unlike previous analyses, we take into account a Higgsino dressing diagram of dimension 5 operator with right-handed matter fields ($RRRR$ operator). It is shown that this diagram gives a significant contribution for $p \to K^{+}\bar{\nu}_{\tau}$. Constraints on the colored Higgs mass $M_C$ and the sfermion mass $m_{\tilde{f}}$ from Super-Kamiokande limit become considerably stronger than those in the previous analyses: $M_C > 6.5\times 10^{16} \gev$ for $m_{\tilde{f}} < 1 \tev$. The minimal model with $m_{\tilde{f}} \lsim 2 \tev$ is excluded if we require the validity of this model up to the Planck scale.