Minding the gap: testing natural anomaly-mediated SUSY breaking at high luminosity LHC

TL;DR

This paper investigates the potential of the high luminosity LHC to explore the remaining viable parameter space of natural AMSB supersymmetry models, focusing on specific collider signatures to either discover or exclude the model.

Contribution

It identifies the intermediate gravitino mass gap in nAMSB models and proposes collider signatures to test this gap at HL-LHC, extending previous constraints.

Findings

HL-LHC can explore the intermediate m_{3/2} gap in nAMSB models.

Certain collider signatures like SSdB, trileptons, and soft dileptons are promising discovery channels.

HL-LHC has the potential to confirm or rule out nAMSB within 3000 fb^{-1} of data.

Abstract

While the minimal anomaly-mediated SUSY breaking model (mAMSB) seems ruled out by constraints on Higgs mass, naturalness and wino dark matter, a slightly generalized version dubbed natural AMSB (nAMSB) remains both viable and compelling. Like mAMSB, nAMSB features winos as the lightest gauginos, but unlike mAMSB, nAMSB allows a small mu parameter so that higgsinos are the lightest of electroweakinos (EWinos). nAMSB spectra depend on the input value of gravitino mass m_{3/2}, where the lower range of m_{3/2} is excluded by LHC gluino pair searches while a higher m_{3/2} band is excluded by LHC limits on wino pair production followed by boosted hadronic wino decays. A remaining intermediate gap in m_{3/2} values remains allowed by present LHC searches, but appears to be completely explorable by high luminosity ugrades of LHC (HL-LHC). We explore a variety of compelling discovery channels that may allow one to close the intermediate gap in m_{3/2} values: 1. same-sign diboson +MET (SSdB) production arising from wino pair production, leading to same-sign dileptons plus MET, 2. trilepton production arising from wino pair production and 3. soft dilepton plus jet events from higgsino pair production, 4. top-squark pair production. From our signal-to-background analysis along a nAMSB model line, we expect HL-LHC to either discover or rule out the nAMSB model with 3000 fb^{-1} of integrated luminosity.