Mono-top signature from stop decay at the HE-LHC

Abstract: Searching for the top squark (stop) is a key task to test the naturalness of SUSY. Different from stop pair production, single stop production relies on its electroweak properties and can provide some unique signatures. Following the single production process $pp \to \tilde t_1 \tilde{\chi}^-_1 \to t \tilde{\chi}^0_1 \tilde{\chi}^-_1$, the top quark has two decay channels: leptonic channel and hadronic channel. In this paper, we probe the observability of these two channels in a simplified MSSM scenario. We find that, at the 27 TeV LHC with the integrated luminosity of ${\cal L} = 15~\text{ab}^{-1}$, $m_{\tilde{t}1}<1900$ GeV and $\mu<750$ GeV can be excluded at $2\sigma$ through the leptonic mono-top channel, while $m{\tilde{t}_1}<1200$ GeV and $\mu<350$ GeV can be excluded at $2\sigma$ through the hadronic channel.