Speaker
Description
Hidden valley / dark sector models can produce multilepton signals with low backgrounds, especially when vectors decay promptly to charged leptons, a signature which remains relatively unexplored. In this talk, I extend our recent recast of an ATLAS four-lepton search to models in which a scalar mediator $S$, singly produced at the LHC, decays to dark gluons, which in turn produce a shower of dark mesons. Dark vector mesons $\rho_D$ can yield same flavor opposite charge dilepton pairs, while dark pions $\pi_D$ remain invisible. I discuss benchmark models with a two-flavor QCD-like dark sector, the treatment of trigger and reconstruction effects in the recast, and the dominant theoretical uncertainties associated with dark showering and hadronization.