Triplet Extended Supersymmetric Standard Model

TL;DR

This paper explores an extension of the MSSM with a triplet superfield, showing it can produce a heavier Higgs boson around 140 GeV with less fine-tuning and enhanced LHC production rates, while addressing theoretical constraints.

Contribution

It introduces a triplet extension to the MSSM that allows a heavier Higgs mass and modifies Higgs phenomenology without requiring heavy top squarks.

Findings

Higgs mass can reach 140 GeV without top-squark contributions

Enhanced gluon-gluon fusion production at the LHC

Allows light stops with Landau poles before GUT scale

Abstract

We revisit an extension of the MSSM by adding a hypercharge-neutral, SU(2)-triplet chiral superfield. Similar to the NMSSM, the triplet gives an additional contribution to the quartic coupling in the Higgs potential, and the mass of the lightest CP-even Higgs boson can be greater than tne mass of the Z-bosn at tree-level. In addition to discussing the perturbativity, fine-tuning, and decoupling issues of this model, we compute the dominant 1-loop corrections to the mass of the lightest CP-even Higgs boson from the triplet sector. When the Higgs-Higgs-Triplet coupling in the superpotential is comparable to the top Yukawa coupling, we find that the Higgs mass can be as heavy as 140 GeV even without the traditional contributions from the top--s-top sector, and at the same time consistent with the precision electroweak constraints. At the expense of having Landau poles before the GUT scale, this opens up a previously forbidden region in the MSSM parameter space where both s-tops are light. In addition to having relatively small fine-tuning (about one part in 30), this leads to a gluo-philic Higgs boson whose production via gluon-gluon fusion at the LHC can be twice as large as the SM prediction.