Consistent simulation of non-resonant diphoton production in hadron collisions including associated jet production up to two jets

TL;DR

This paper presents a new event generator for diphoton production in hadron collisions that accurately models associated jet production up to two jets, incorporating QED and QCD radiation, and aligns well with LHC data.

Contribution

The paper introduces a novel simulation method combining subtraction and parton shower techniques to model diphoton events with up to two jets, including loop-mediated processes.

Findings

Simulated diphoton kinematics agree with LHC measurements.

2-jet processes significantly contribute to diphoton production.

The method enables realistic photon isolation and jet reconstruction simulations.

Abstract

An event generator for diphoton ($\gamma\gamma$) production in hadron collisions that includes associated jet production up to two jets has been developed using a subtraction method based on the LLL subtraction. The parton shower (PS) simulation to restore the subtracted divergent components involves both QED and QCD radiation, and QED radiation at very small $Q^{2}$ are simulated by referring to a fragmentation function (FF). The PS/FF simulation has the ability to enforce the radiation of a given number of energetic photons. The generated events can be fed to PYTHIA to obtain particle (hadron)-level event information, which enables us to perform realistic simulations of photon isolation and hadron-jet reconstruction. The simulated events, in which the loop-mediated $gg \rightarrow \gamma\gamma$ process is involved, reasonably reproduce the diphoton kinematics measured at the LHC. Using the developed simulation, we found that the 2-jet processes significantly contribute to diphoton production. A large 2-jet contribution can be considered as a common feature in electroweak-boson production in hadron collisions although the reason is yet to be understood. Discussion concerning the treatment of the underlying events in photon isolation is necessary for future higher precision measurements.