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

Abstract

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 $$m_h\sim 125$$ m h ∼ 125 GeV. Within the RNS framework, gluinos dominantly decay via $$\tilde{g}\rightarrow t\tilde{t}_1^{*},\ \bar{t}\tilde{t}_1 \rightarrow t\bar{t}\widetilde{Z}_{1,2}$$ g ~ → t t ~ 1 ∗ , t ¯ t ~ 1 → t t ¯ Z ~ 1 , 2 or $$t\bar{b}\widetilde{W}_1^-+c.c.$$ t b ¯ W ~ 1 - + c . c . , where the decay products of the higgsino-like $$\widetilde{W}_1$$ W ~ 1 and $$\widetilde{Z}_2$$ Z ~ 2 are very soft. Gluino pair production is, therefore, signaled by events with up to four hard b-jets and large $$\not \!\!{E_T}$$ ⧸ 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 $$m_{\tilde{g}} < 2400 \ (2800)$$ m g ~ < 2400 ( 2800 ) GeV for an integrated luminosity of 300 (3000) fb $$^{-1}$$ - 1 . We also show that the measurement of the rate of gluino events in the clean sample mentioned above allows for a determination of $$m_{\tilde{g}}$$ m 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 5 $$\sigma $$ σ discovery is possible at the LHC.