Stau pairs from natural SUSY at high luminosity LHC

Natural supersymmetry (SUSY) with light higgsinos is perhaps the most plausible of all weak scale SUSY models while a variety of motivations point to (right) tau sleptons as the lightest of all the sleptons. We examine a SUSY model line with rather light right-staus embedded within natural SUSY. For light stau₁ of a few hundred GeV, then the decays stau₁ -> ₁, ₂⁰ and _₁^- occur at comparable rates where the (higgsino-like) ₁^ and ₂⁰ release only small visible energy: in this case, the expected ^+^- + signature is diminished from usual expectations due to the presence of the nearly invisible decay mode ₁ -> _₁^-. However, once m䃑> ~m (bino), then decays to binos such as ₁ -> ₃⁰ open up where ₃⁰ decays to higgsinos plus W^, Z⁰ and h at comparable rates. For these heavier staus, then stau pair production gives rise to diboson+ events which may contain 0, 1 or 2 additional hard leptons. From these considerations, we examine the potential for future discovery of tau-slepton pair production at high-luminosity LHC. While we do not find a 5 HL-LHC discovery reach for 3000 fb^-1, we do find a 95\% CL exclusion reach, ranging between m䃑: 100-450 GeV for m䃑䃀~ 100 GeV. This latter reach disappears for m䃑䃀>~ 200 GeV.