Kinematic Cusps with Two Missing Particles II: Cascade Decay Topology

TL;DR

This paper analyzes the properties of cusped peak structures in cascade decays with missing particles, showing how to determine particle masses from kinematic features while accounting for realistic effects.

Contribution

It introduces a detailed study of cusp and endpoint features in cascade decays, enabling mass measurements even with realistic experimental considerations.

Findings

Cusps and endpoints can determine missing and intermediate particle masses.

Realistic effects like decay widths and boosts are manageable.

Kinematic distributions exhibit predictable cusp structures.

Abstract

Three-step cascade decays into two invisible particles and two visible particles via two intermediate on-shell particles develop cusped peak structures in several kinematic distributions. We study the basic properties of the cusps and endpoints in various distributions and demonstrate that the masses of the missing particles and the intermediate particles can be determined by the cusp and endpoint positions. Effects from realistic considerations such as finite decay widths, longitudinal boost of the parent particle, and spin correlations are shown to be under control for the processes illustrated.