# Analysis of Long Lived Particle Decays with the MATHUSLA Detector

## TL;DR

This paper explores how the MATHUSLA detector can identify and analyze long-lived particles produced at the LHC, including measuring their mass, decay modes, and production characteristics with limited decay information.

## Contribution

It demonstrates the potential of MATHUSLA to measure properties of long-lived particles, such as mass and decay modes, using minimal decay product information.

## Key findings

- Mass of long-lived particle can be measured with fewer than 100 events.
- Decay mode can be identified with limited decay product data.
- Production mode and spin can be distinguished in general cases.

## Abstract

The MATHUSLA detector is a simple large-volume tracking detector to be located on the surface above one of the general-purpose experiments at the Large Hadron Collider. This detector was proposed in [1] to detect exotic, neutral, long-lived particles that might be produced in high-energy proton-proton collisions. In this paper, we consider the use of the limited information that MATHUSLA would provide on the decay products of the long-lived particle. For the case in which the long-lived particle is pair-produced in Higgs boson decays, we show that it is possible to measure the mass of this particle and determine the dominant decay mode with less than 100 observed events. We discuss the ability of MATHUSLA to distinguish the production mode of the long-lived particle and to determine its mass and spin in more general cases.