Extracting the dark matter mass from single stage cascade decays at the LHC

We explore a variant on the M_T2 kinematic variable which enables dark matter mass measurements for simple, one stage, cascade decays. This will prove useful for constraining a subset of supersymmetric processes, or a class of leptophilic dark matter models at the LHC. We investigate the statistical reach of these measurements and discuss which sources of error have the largest effects. For example, we find that using only single stage cascade decays with initial state radiation, a measurement of a 150GeV dark matter candidate can be made to O(10%) for a parent mass of 300GeV with a production cross section of 100 fb and 100 fb^-1 of integrated luminosity provided that backgrounds can be tightly controlled.