Searching for a particle of unknown mass and lifetime in the presence of an unknown non-monotonic background

TL;DR

This paper introduces a rapid method for detecting unknown low-mass particles with uncertain lifetimes amidst complex backgrounds, enhancing experimental search capabilities in particle physics.

Contribution

It proposes a novel, efficient approach for significance assessment and limit setting in searches for unknown particles with non-monotonic backgrounds.

Findings

The method improves detection sensitivity for unknown particles.

It effectively handles complex, non-monotonic background signals.

The approach is computationally efficient and adaptable.

Abstract

Many extensions to the Standard Model of particle physics hypothesize the existence of new low-mass particles. Typically there are few theoretical constraints on the mass or lifetime of such particles. This requires the experimentalist to perform a search in which both the mass and lifetime of the particle are unknown. Such searches for low-mass particles are complicated by the possible presence of resonances and other non-monotonic backgrounds. This paper presents a simple and fast approach to assigning significance and setting limits in such searches.