2022-01-07 11:00  P5A-1

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

Dibyashree Sengupta

Motivated by the fact that naturalness arguments strongly suggest that the SUSY-preserving higgsino mass parameter µ 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 l+l- + MET + j events from the production and subsequent decay, ilde{chi}^0_2 → ilde{chi}^0_1 l+ l-, of the heavier neutral higgsino. The novel feature of our analysis is that we suggest angular cuts to reduce the important background from Z(→ tau tau ) + j events more efficiently than the m^2_{tau tau} < 0 cut that has been used by the ATLAS and CMS collaborations. Other cuts, needed to reduce backgrounds from tt¯, WW j and W/Z + lar{l} 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.