Gluino reach and mass extraction at the LHC in radiatively-driven natural SUSY

Abstract

Radiatively-driven natural SUSY (RNS) models enjoy electroweak naturalness at the 10% level while respecting LHC sparticle and Higgs mass constraints. Gluino and top-squark masses can range up to several TeV (with other squarks even heavier) but a set of light Higgsinos are required with mass not too far above m_hsim 125 GeV. Within the RNS framework, gluinos dominantly decay via tilde{g}rightarrow ttilde{t}_1^{*}, bar{t}tilde{t}_1 rightarrow tbar{t}widetilde{Z}_{1,2} or tbar{b}widetilde{W}_1^-+c.c., where the decay products of the higgsino-like widetilde{W}_1 and widetilde{Z}_2 are very soft. Gluino pair production is, therefore, signaled by events with up to four hard b-jets and large not !!{E_T}. We devise a set of cuts to isolate a relatively pure gluino sample at the (high-luminosity) LHC and show that in the RNS model with very heavy squarks, the gluino signal will be accessible for m_{tilde{g}} < 2400 (2800) GeV for an integrated luminosity of 300 (3000) fb^{-1}. We also show that the measurement of the rate of gluino events in the clean sample mentioned above allows for a determination of m_{tilde{g}} with a statistical precision of 2–5% (depending on the integrated luminosity and the gluino mass) over the range of gluino masses where a 5sigma discovery is possible at the LHC.