Abstract
The MT2 or "s-transverse mass" statistic was developed to associate a parent mass scale to a missing transverse energy signature, given that escaping particles are generally expected in pairs, while collider experiments are sensitive to just a single transverse momentum vector sum. This document focuses on the generalized extension of that statistic to asymmetric one- and two-step decay chains, with arbitrary child particle masses and upstream missing transverse momentum. It provides a unified theoretical formulation, complete solution classification, taxonomy of critical points, and technical algorithmic prescription for treatment of the MT2 event scale. An implementation of the described algorithm is available for download, and is also a deployable component of the author's selection cut software package AEACuS (Algorithmic Event Arbiter and Cut Selector). Appendices address combinatoric event assembly, algorithm validation, and a complete pseudocode.
Highlights
The MT2, or “s-transverse mass”, statistic was developed to associate a parent mass scale to a missing transverse energy signature, given that escaping particles are generally expected in pairs, while collider experiments are sensitive to just a single transverse momentum vector sum
A broader context for the practical usage of this algorithm is provided by its inclusion in the author’s fully-featured selection cut software package AEACuS — in Greek myth, the judges Minos, Rhadamanthus and Aeacus, sons of Zeus, weigh the fate of souls departing the mortal sphere — (Algorithmic Event Arbiter and Cut Selector), which was formerly developed under the name CutLHCO [13, 14]
The MT2, or “s-transverse mass”, statistic was developed to cope with the difficulty of associating a parent mass scale with a missing transverse energy signature, given that models of new physics generally predict production of escaping particles in pairs, while collider experiments are sensitive to just a single vector sum over all sources of missing transverse momentum
Summary
The event topologies addressed by the s-transverse mass scale statistic family MT2 begin with pair production of a massive parent particle species Y , possibly accompanied by some component of upstream transverse momentum. The longitudinal component of PHμ is experimentally inaccessible, but obviously still bounded to positive magnitude-square (PHz )2 ≥ 0 This inequality may be projected back onto the transverse components (PHx,y) of the hidden momentum vector, defining a bounded consistency region in that coordinate plane for each trial value of the parent mass MY that admits real solutions. (2.3), which perform a mapping of either event leg’s kinematically consistent solution space into the conjugate leg’s (PHx , PHy ) hidden momentum plane These coefficients are provided subsequently, in terms of the referenced leg’s native coefficient set from eqs. The MT2 statistic is recognized as the smallest trial value of MY , if any, that is capable of producing an intersection between the overlaid regions of kinematic consistency for the two event legs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
