OPTIMASS: A Package for the Minimization of Kinematic Mass Functions with Constraints

Abstract

Reconstructed mass variables, such as M2, M2C, M? T , and MW T2, play an essential role in searches for new physics at hadron colliders. The calculation of these variables generally involves constrained minimization in a large parameter space, which is numerically challenging. We provide a C++ code, Optimass, which interfaces with the Minuit library to perform this constrained minimization using the Augmented Lagrangian Method. The code can be applied to arbitrarily general event topologies, thus allowing the user to signicantly extend the existing set of kinematic variables. We describe this code, explain its physics motivation, and demonstrate its use in the analysis of the fully leptonic decay of pair-produced top quarks using M2 variables. (c) 2016 Journal of High Energy Physics