Mixing It Up With MT2: Unbiased Mass Measurements at Hadron Colliders

Understand

Recently, much progress has been made on techniques to measure the masses of new particles with partially-invisible decays at a hadron collider.

• We examine for the first time the realistic application of MT2-based measurement methods to a fully hadronic final state from a symmetric two-step decay chain with maximal combinatorial uncertainty.
• Several problems arise in such an analysis: the MT2 variables are powerful but fragile, with shallow edges that are easily washed out or faked by ubiquitous combinatorics background.
• Traditional methods of both cleaning up the distribution and determining edge position can fail badly.