On messengers couplings in extended GMSB models

TL;DR

This paper explores how superpotential couplings among three messenger fields in an extended GMSB model affect soft mass contributions, influencing particle spectra and potential collider signatures.

Contribution

It introduces the role of messenger three-field couplings in GMSB models with SU(5) multiplets, deriving their impact on soft masses and phenomenology.

Findings

Extra contributions to 2-loop soft masses from messenger couplings.

Masses of the lightest sleptons are highly sensitive to these interactions.

Possible NLSP/NNLSP patterns include stau or selectron lighter than neutralino.

Abstract

We discuss, for the first time, the role of the superpotential couplings of three messenger fields in a GMSB-type unification model in which messenger sector consists of both 5+5bar and 10+10bar of SU(5). It turns out that these interactions are relevant when coexist with appropriate messenger-MSSM couplings. Then they induce extra contributions to 2-loop soft masses. In the present model, we derive all such soft terms and discuss constraints which have to be satisfied to avoid rapid proton decay and mu/B_mu problem. As an example, it is shown how superpotential couplings of three messengers influence mass spectra when the model is restricted by additional global U(1)_q symmetry. We find that masses of the lightest sleptons are the most sensitive to those new interactions, what in some cases results in the NLSP/NNLSP pattern in which stau or selectron is lighter than the lightest neutralino.