Cracking Down on Fake Photons - A Case of 750 GeV Diphoton Resonance -

TL;DR

This paper investigates how to distinguish a 750 GeV diphoton resonance decaying into photon-jets from a true diphoton resonance by analyzing detector responses, focusing on photon conversion signatures.

Contribution

It introduces a method to differentiate photon-jet signals from genuine diphoton signals using the sum of transverse momentum from photon conversions.

Findings

Sum of p_T of e+e- pairs effectively discriminates photon-jets from diphotons.

Photon conversion point measurements can estimate the lifetime of intermediate particles.

Detector response analysis enhances identification of photon-jet events.

Abstract

Among various models to explain the $750$ GeV diphoton resonance hinted at the LHC Run 2, a class of models where the resonance decays not into a pair of photons but into a pair of photon-jets is gathering definite attention. In this paper, we study how well we can distinguish the di-photon-jet resonance from the diphoton resonance by examining detector responses to the photon-jets. We find that the sum of $p_T$ of the first $e^+e^-$ pair from the photon conversion provides strong discrimination power. We also discuss determination of the lifetime of the light intermediate particle by measuring the photon conversion points.