A short comparison between mT2 and mCT

We compare mT2 with mCT ; both are kinematic variables designed to find relationships between masses of pair-produced new states with symmetric decay chains. We find that for massless visible particles mCT equals mT2 in a particular limit. We identify advantages and disadvantages to the use of each variable. Tovey’s paper on mCT also introduced a powerful concept of extracting mass information from an analysis at intermediate stages of a symmetric decay chain. We suggest that mT2 is a better tool for performing this analysis than mCT due to mT2’s better properties under initial state radiation.