Supersymmetric particle mass measurement with the boost-corrected contransverse mass

A modification to the contransverse mass (M-CT) technique for measuring the masses of pair-produced semi-invisibly decaying heavy particles is proposed in which M-CT is corrected for non-zero boosts of the centre-of-momentum (CoM) frame of the heavy states in the laboratory transverse plane. Lack of knowledge of the mass of the CoM frame prevents exact correction for this boost, however it is shown that a conservative correction can nevertheless be derived which always generates an M-CT value which is less than or equal to the true value of M-CT in the CoM frame. The new technique is demonstrated with case studies of mass measurement with fully leptonic t (t) over bar events and with SUSY events possessing a similar final state.