Extrapolation Technique Pitfalls in Asymmetry Measurements at Colliders

TL;DR

This paper discusses the challenges and pitfalls in extrapolating asymmetry measurements at colliders, highlighting how small simulated asymmetries can require large sample sizes for reliable estimates.

Contribution

It identifies a specific pitfall in using simulation-based extrapolation factors when the simulated asymmetry is small, and quantifies the sample size needed.

Findings

The required number of simulated events increases as the inverse square of the simulated asymmetry.

Small simulated asymmetries can lead to unreliable extrapolation factors without large sample sizes.

A potential pitfall in collider asymmetry analysis that can be avoided with proper simulation strategies.

Abstract

Asymmetry measurements are common in collider experiments and can sensitively probe particle properties. Typically, data can only be measured in a finite region covered by the detector, so an extrapolation from the visible asymmetry to the inclusive asymmetry is necessary. Often a constant multiplicative factor is more than adequate for the extrapolation and this factor can be readily determined using simulation methods. However, there is a potential, avoidable pitfall involved in the determination of this factor when the asymmetry in the simulated data sample is small. We find that to obtain a reliable estimate of the extrapolation factor, the number of simulated events required rises as the inverse square of the simulated asymmetry; this can mean that an unexpectedly large sample size is required when determining its value.