A solution to the little hierarchy problem in a partly N=2 extension of the MSSM

TL;DR

This paper proposes a partly N=2 extended MSSM model with Dirac gauginos and enhanced symmetry, addressing the little hierarchy problem by controlling radiative corrections to the Higgs mass, and predicts distinctive LHC signatures.

Contribution

It introduces a novel N=2 extension of the MSSM with specific gauge symmetry, providing a new solution to the little hierarchy problem and phenomenological implications.

Findings

Controllable radiative corrections to Higgs mass from stop loops.

Heavy Dirac gauginos can coexist with light scalar masses.

Distinct LHC signatures from exotic sfermions and Dirac gauginos.

Abstract

We extend a model of the Dirac gauginos, which originate from N=2 supersymmetry (SUSY) for the gauge sector, such that the N=2 SUSY is imposed also to the sfermion sector but only for the 3rd generation squarks and sleptons. In addition to the N=2 supersymmetry, our model is constructed based on the SU(3)c times SU(3)L times U(1)' gauge symmetry. By this extension, the dominant source of radiative correction to the Higgs mass squared coming from the stop loop becomes controllable based on the enhanced symmetry. Then it becomes a viable model which provides a solution to the little hierarchy problem in SUSY models. Even in the original scenario, the Dirac gauginos can be superheavy, of order 10 TeV or so, while keeping the scalar masses at the weak scale. This possibility is phenomenologically interesting because it can suppress the unwanted flavor changing processes. And in scope of the LHC, this scenario can have a very distinct signature related to the exotic sfermions which are accompanied as the N=2 superpartners as well as the Dirac gauginos.