New angular (and other) cuts to improve the higgsino signal at the LHC

TL;DR

This paper proposes new angular cuts to enhance the detection of higgsino signals at the HL-LHC, focusing on reducing background noise more effectively than previous methods, to improve the search for natural SUSY models.

Contribution

It introduces novel angular cuts for higgsino searches that outperform traditional background suppression techniques at the HL-LHC.

Findings

Angular cuts improve background rejection efficiency.

Higgsino signals can be characterized with new distribution analyses.

Potential to detect higgsinos in natural SUSY scenarios at LHC14.

Abstract

Motivated by the fact that naturalness arguments strongly suggest that the SUSY-preserving higgsino mass parameter mu cannot be too far above the weak scale, we re-examine higgsino pair production in association with a hard QCD jet at the HL-LHC. We focus on \ell^+\ell^-+\eslt+j events from the production and subsequent decay, \tchi_2^0\to\tchi_1^0\ell^+\ell^-, of the heavier neutral higgsino. The novel feature of our analysis is that we suggest angular cuts to reduce the important background from Z(\to \tau\tau)+j events more efficiently than the m_{\tau\tau}^2<0 cut that has been used by the ATLAS and CMS collaborations. Other cuts, needed to reduce backgrounds from t\bar{t}, WWj and W/Z+\ell\bar{\ell} production, are also delineated. We plot out the reach of LHC14 for 300 and 3000~fb^{-1} and also show distributions that serve to characterize the higgsino signal, noting that higgsinos may well be the only superpartners accessible at LHC14 in a well-motivated class of natural SUSY models.