Early SUSY discovery at LHC without missing E_T: the role of multi-leptons

TL;DR

This paper demonstrates that SUSY signals at the LHC can be discovered without relying on missing transverse energy by using multi-lepton signatures, enabling early detection despite calibration issues.

Contribution

It introduces a method to detect SUSY at the LHC using multi-lepton events without missing E_T, expanding search strategies for early data.

Findings

SUSY can be discovered with 0.1-1 fb^{-1} of data without missing E_T.

Requiring ≥3 isolated leptons and jets effectively suppresses background.

Mass reconstruction is feasible through kinematic analysis even without missing E_T.

Abstract

Traditional searches for SUSY at hadron colliders rely heavily on the presence of large missing transverse energy (ME_T) to reject background compared to signal. On the other hand, initial searches for new physics at the LHC may not be able to rely on ME_T due to a variety of detector calibration issues. We show that much of SUSY parameter space is accessible to discovery even {\it without} using ME_T, and with rather low integrated luminosities 0.1-1 fb^{-1}. A key role is played by isolated lepton multiplicity which arises from gluino and squark cascade decays. Requiring \ge 3 isolated leptons plus jets yields a high rate of background rejection compared to signal. We find an LHC reach in m(gluino) of about 700-750 GeV for just 0.1 fb^{-1} of integrated luminosity by requiring events with \ge 4 jets plus \ge 3 isolated leptons but {\it without} using ME_T. If a large enough event sample is assembled, then kinematic reconstruction of sparticle mass properties should be possible just as in the case where large ME_T is required. SUSY without ME_T can also be seen in opposite-sign/same flavor {\it dilepton plus jets} events when a characteristic invariant mass edge stands out against background.