MSSM4G: Reviving Bino Dark Matter with Vector-like 4th Generation Particles

TL;DR

This paper proposes extending the MSSM with vector-like 4th generation particles to address Higgs mass, naturalness, and Bino dark matter relic density, compatible with current experimental constraints.

Contribution

It introduces vector-like 4th generation particles into MSSM, enabling correct Bino dark matter relic density and raising Higgs mass without heavy superpartners.

Findings

New annihilation channels for Bino dark matter are identified.

Parameter space exists where Higgs mass, relic density, and experimental constraints are satisfied.

Gauge coupling unification is preserved with the extended model.

Abstract

We supplement the minimal supersymmetric standard model (MSSM) with vector-like copies of standard model particles. Such 4th generation particles can raise the Higgs boson mass to the observed value without requiring very heavy superpartners, improving naturalness and the prospects for discovering supersymmetry at the LHC. Here we show that these new particles are also motivated cosmologically: in the MSSM, pure Bino dark matter typically overcloses the Universe, but 4th generation particles open up new annihilation channels, allowing Binos to have the correct thermal relic density without resonances or co-annihilation. We show that this can be done in a sizable region of parameter space while preserving gauge coupling unification and satisfying constraints from collider, Higgs, precision electroweak, and flavor physics.