Monojets and monophotons from light Higgsino pair production at LHC14

Abstract

Naturalness arguments imply the existence of Higgsinos lighter than 200--300 GeV. However, because these Higgsinos are nearly mass degenerate, they release very little visible energy in their decays, and signals from electroweak Higgsino pair production typically remain buried under Standard Model backgrounds. Moreover, gluinos, squarks and winos may plausibly lie beyond the reach of the LHC14, so that signals from naturalness-inspired supersymmetric models may well remain hidden via conventional searches. We examine instead prospects for detecting Higgsino pair production via monojets or monophotons from initial-state radiation. We find typical signal-to-background rates at best at the 1% level and without any spectral distortions, leading to rather pessimistic conclusions regarding detectability via these channels.