Probing the origin of 750 GeV diphoton excess with the precision measurements at the ILC

TL;DR

This paper explores how precision measurements at the ILC can indirectly probe and distinguish models explaining the 750 GeV diphoton excess, focusing on the effects of new charged particles on scattering processes.

Contribution

It demonstrates that the ILC can test models with new charged particles responsible for the diphoton excess through indirect effects on fermion pair production.

Findings

ILC measurements can indirectly detect new charged particles affecting $e^+e^- o far{f}$.

Angular distributions of fermion pairs can help discriminate between different diphoton models.

The study provides a method to test the diphoton excess models beyond direct production reach.

Abstract

The recently reported diphoton excess at the LHC may imply the existence of a new resonance with a mass of about 750 GeV which couples to photons via loops of new charged particles. In this letter, we study the possibility to test such models at the ILC, paying attention to the new charged particles responsible for the diphoton decay of the resonance. We show that they affect the scattering processes $e^+e^- \to f\bar{f}$ (with $f$ denoting Standard Model fermions) at the ILC, which makes it possible to indirectly probe the new charged particles even if they are out of the kinematical reach. We also show that the discriminations of the diphoton models may be possible based on a study of the angular distributions of $f\bar{f}$.