Light Nondegenerate Squarks at the LHC

Experimental bounds on squarks of the first two generations assume their masses to be eightfold degenerate and consequently constrain them to be heavier than similar to 1.4 TeV when the gluino is lighter than 2.5 TeV. The assumption of squark-mass universality is neither a direct consequence of minimal flavor violation (MFV), which allows for splittings within squark generations, nor a prediction of supersymmetric alignment models, which allow for splittings between generations. We reinterpret a recent CMS multijet plus missing energy search allowing for deviations from U(2) universality and find significantly weakened squark bounds: A 400 GeV second-generation squark singlet is allowed, even with exclusive decays to a massless neutralino, and, in an MFV scenario, the down-type squark singlets can be as light as 600 GeV, provided the up-type singlets are pushed up to 1.8 TeV, for a 1.5 TeV gluino and decoupled doublet squarks. DOI: 10.1103/PhysRevLett.110.151804