Search for selectrons and smuons at $\sqrt{s}=13$ TeV

A search for direct production of the supersymmetric partners of electrons and muons is presented in final states with two opposite-charge, same-flavor leptons (electrons and muons), little hadronic activity, and missing transverse momentum. The data sample corresponds to an integrated luminosity of $35.9~\text{fb}^{-1}$ of proton-proton collisions at $\sqrt{s}=13~\text{TeV}$ collected with the CMS detector at the LHC in 2016. The analysis uses the $M_\text{T2}$ variable which generalizes the transverse mass for systems with two invisible objects, and exhibits an endpoint for standard model backgrounds containing a W boson. The observed yields are consistent with the expectations from the standard model, and the results are interpreted in the context of simplified models of supersymmetry, resulting in observed (expected) limits at the $95\%$ confidence level on the left-handed slepton mass of up to 400 (450) GeV and on the right-handed slepton mass of up to 290 (330) GeV for massless LSP, improving the existing limits by approximately 150 (200) GeV.