New Physics contamination to precision luminosity measurements at future $e^+e^-$ colliders

TL;DR

This paper investigates how potential New Physics effects could contaminate the precision luminosity measurements at future electron-positron colliders, emphasizing the importance of understanding and mitigating these uncertainties for accurate physics analysis.

Contribution

It provides an exploratory analysis of New Physics contributions to Bhabha scattering and discusses strategies to mitigate their impact on luminosity measurements.

Findings

New Physics can significantly affect Bhabha scattering cross sections.

Certain observables can be used to cancel out luminosity uncertainties.

Strategies to isolate pure Standard Model signals are proposed.

Abstract

Several key observables of the high-precision physics program at future lepton colliders will critically depend on the knowledge of the absolute machine luminosity. The determination of the luminosity relies on the precise knowledge of some reference process, which is in principle not affected by unknown physics, so that its cross section can be computed within a well-established theory, like the Standard Model. Quantifying the uncertainties induced by possible New Physics effects on such processes is therefore crucial. We present an exploratory investigation of light and heavy New Physics contributions to the small-angle Bhabha process at future $e^+e^-$ colliders and we discuss possible strategies to remove potential uncertainties originating from such contaminations by relying on observables that are independent of the absolute luminosity.