All of our discussion throughout the paper will be completely model - independent and can be applied to any BSM scenario , including supersymmetry , extra dimensions , little Higgs theory etc . In Section 5 , however , we shall use a specific example in order to illustrate each of our three proposed methods . Instead of considering a decay chain of some BSM model , we chose to select an example which is already present in the Tevatron data , and will soon be tested at the LHC as well : the dilepton event samples from top quark pair production and from W -pair production . Those two dilepton samples satisfy all of our assumptions , and would be a perfect testing ground for any new ideas about mass measurements in missing energy events from new physics . In Section 5 we will show that using any one of our three M T 2 -based mass measurement methods , one can in principle determine the mass of each of the three particles : top quark , W -boson , and neutrino , independently and in a completely modelindependent fashion . Section 6 contains a summary and a discussion of our main results . In Appendix A we collect all relevant formulas for the endpoint functions M ( n , p , c ) T 2,max ( M c , p T ) .