Effective Supersymmetry at the LHC

TL;DR

This paper explores the phenomenology of Effective Supersymmetry models with specific mass hierarchies, analyzing their viability, dark matter implications, and distinctive LHC signatures such as b-jet rich events.

Contribution

It introduces a detailed analysis of ESUSY models with independent GUT scale parameters, providing benchmark points and LHC phenomenology insights.

Findings

ESUSY models can be consistent with current constraints.

Dark matter may be an axion/axino mixture due to LMP decay.

LHC signatures include gluino and third generation squark production, with b-jet rich events.

Abstract

We investigate the phenomenology of Effective Supersymmetry (ESUSY) models wherein electroweak gauginos and third generation scalars have masses up to about 1~TeV while first and second generation scalars lie in the multi-TeV range. Such models ameliorate the SUSY flavor and CP problems via a decoupling solution, while at the same time maintaining naturalness. In our analysis, we assume independent GUT scale mass parameters for third and first/second generation scalars and for the Higgs scalars, in addition to m_{1/2}, \tan\beta and A_0, and require radiative electroweak symmetry breaking as usual. We analyse the parameter space which is consistent with current constraints, by means of a Markov Chain Monte Carlo scan. The lightest MSSM particle (LMP) is mostly, but not always the lightest neutralino, and moreover, the thermal relic density of the neutralino LMP is frequently very large. These models may phenomenologically be perfectly viable if the LMP before nucleosynthesis decays into the axino plus SM particles. Dark matter is then an axion/axino mixture. At the LHC, the most important production mechanisms are gluino production (for m_{1/2} ~<700~GeV) and third generation squark production, while SUSY events rich in b-jets are the hallmark of the ESUSY scenario. We present a set of ESUSY benchmark points with characteristic features and discuss their LHC phenomenology.