  We introduce a new collider variable, MCT2, named as constransverse mass. It
is a mixture of `stransverse mass(MT2)' and `contransverse mass(MCT)'
variables, where the usual endpoint structure of MT2 distribution can be
amplified in the MCT2 basis by large Jacobian factor which is controlled by
trial missing particle mass. Thus the MCT2 projection of events increases our
observability to measure several important endpoints from new particle decays,
which are usually expected to be buried by irreducible backgrounds with various
systematic uncertainties at the LHC. In this paper we explain the phenomenology
of endpoint amplification in MCT2 projection, and describe how one may employ
this variable to measure several meaningful mass constraints of new particles.
