Sensitivity of searches for new signals and its optimization

TL;DR

This paper discusses a frequentist definition of search sensitivity that is applicable, interpretable, and useful for optimizing detection strategies without relying on prior signal expectations.

Contribution

It introduces a new, universally applicable sensitivity measure based on standard frequentist concepts, suitable for both setting limits and discovering new phenomena.

Findings

Provides a clear interpretation of sensitivity in search analyses

Offers simple formulas for Poisson counts with background

Enables optimization of search criteria independently of prior expectations

Abstract

A frequentist definition of sensitivity of a search for new phenomena is discussed, that has several useful properties. It is based on completely standard concepts, is generally applicable, and has a very clear interpretation. It is particularly suitable for optimization, being independent of a-priori expectations about the presence of a signal, thus allowing the determination of a single set of cuts that is optimal both for setting limits and for making a discovery. Simple approximate formulas are given for the common problem of Poisson counts with background.