FPMC: a generator for forward physics

TL;DR

FPMC addresses the need for a unified Monte Carlo generator of forward physics at hadron colliders, enabling simulation of central high-mass production with one or two intact protons across exclusive and inclusive diffractive topologies. It combines QED and QCD color-singlet exchanges within a single framework by embedding forward-diffractive processes into HERWIG 6.500, implementing the KMR (Durham) and CHIDe (Liege) exclusive models, the Ingelman-Schlein inclusive approach, and rescattering corrections via survival probabilities. The paper details model implementations, parameter controls (NFLUX, TYPEPR, TYPINC), and PDF choices, providing a practical tool for predicting forward-proton signatures and facilitating comparisons to experimental data and beyond-Standard-Model scenarios. Overall, FPMC aims to streamline forward-physics predictions at the LHC by consolidating disparate models into one accessible generator with a consistent hadronization framework.

Abstract

We present the Forward Physics Monte Carlo (FPMC) designed to simulated central particle production with one or two leading intact protons and some hard scale in the event. The underlying interaction between protons or anti-protons through singlet exchange can manifest itself in many forms. The following production mechanisms are implemented: single diffractive dissociation, double pomeron exchange, and exclusive production due to two-gluon or two-photon exchanges. With increasing beam center-of-mass-energies, the production of new final states become possible at the LHC. The aim of FPMC is to implement these processes in one common framework.