SUSY signals with small and large trilinear couplings at the LHC 7 TeV runs and neutralino dark matter

TL;DR

This paper proposes specific LHC 7 TeV signals sensitive to the trilinear coupling parameter in mSUGRA, highlighting their potential to explore parameter space consistent with Higgs mass bounds and dark matter relic density.

Contribution

It introduces new collider signals that are sensitive to the trilinear coupling parameter A0 in mSUGRA, expanding the search strategies for supersymmetry at the LHC.

Findings

Signals are sensitive to A0 and tanβ in mSUGRA.

Parameter space with large negative A0 is consistent with Higgs and dark matter constraints.

Light top squark is a natural consequence of large A0.

Abstract

We propose the signal $1b+1l+N_j+\etslash$ along with appropriate selection criteria for the LHC 7 TeV run, where the number of jets $(N_j)$ is $\ge$ 2 or 4. These signals can complement the canonical $Jets + \etslash$ signature since they are sensitive to the trilinear soft breaking parameter $(A_0)$ and low values of the parameter tan$\beta$ in the minimal supergravity (mSUGRA) model. A large region of this mSUGRA parameter space within the reach of the ongoing experiments at the LHC is disfavoured by the bound on the lightest Higgs boson mass ($m_h \ge 114.4 $ GeV) unless $A_0$ has moderate to large negative values. Interestingly this parameter space with $A_0 \ne 0$ is also consistent with the observed dark matter relic density. A natural consequence of large $A_0$ is the existence of a light top squark ($\lstop$). The proposed signals primarily stem from direct $\lstop \lstop^*$ production and/or $\tilde g \ra \tilde t_{1} t $, if all squark-gluino events are considered. A thorough analysis of the signals and the corresponding backgrounds are presented using the event generator Pythia. We finally compare the signal size for $A_0 = 0$ and $A_0 \ne 0$.