Improved Energy Reconstruction with Generalized Particle Decays by Applying Multiple Constraints

Abstract

Mass constrained fitting is a technique that improves jet energy resolution. The fit is performed by assigning a well-known mass to a decaying particle and minimizing a χ 2 consisting of the constituent particle’s measured parameters. This technique is utilized in an abstract frame work which applies multiple constraints to arbitrary multi- generational particle topologies. The software is constructed with the ability to both fit designated particles and automate the analysis of all particle parameters post-fit, including Monte Carlo information. The energy reconstruction is tested for single and multiple constraints in the decays of J/ψ → μ + μ − , π 0 → γγ, η → π + π − γ, and η → π + π − π 0 .