  We consider SUSY-like missing energy events at hadron colliders and
critically examine the common assumption that the missing energy is the result
of two identical missing particles. In order to experimentally test this
hypothesis, we generalize the subsystem MT2 variable to the case of asymmetric
event topologies, where the two SUSY decay chains terminate in different
"children" particles. In this more general approach, the endpoint MT2max of the
MT2 distribution now gives the mass Mp(Mc(a),Mc(b)) of the parent particle as a
function of two input children masses Mc(a) and Mc(b). We propose two methods
for an independent determination of the individual children masses Mc(a) and
Mc(b). First, in the presence of upstream transverse momentum P(UTM) the
corresponding function Mp(Mc(a),Mc(b),P(UTM)) is independent of P(UTM) at
precisely the right values of the children masses. Second, the previously
discussed MT2 "kink" is now generalized to a "ridge" on the 2-dimensional
surface Mp(Mc(a),Mc(b)). As we show in several examples, quite often there is a
special point along that ridge which marks the true values of the children
masses. Our results allow collider experiments to probe a multi-component dark
matter sector directly and without any theoretical prejudice.
