GRANIITTI: A Monte Carlo Event Generator for High Energy Diffraction

TL;DR

GRANIITTI is a modern, multithreaded Monte Carlo event generator designed for high energy diffraction studies, capable of simulating exotic QCD phenomena like glueballs with advanced spin and interference modeling.

Contribution

It introduces a comprehensive, multithreaded Monte Carlo generator for high energy diffraction, incorporating various scattering amplitudes and spin analysis tools, focusing on the low-mass domain and exotic QCD phenomena.

Findings

Demonstrates state-of-the-art simulation capabilities

Shows how the glueball filter observable is influenced by spin polarization

Integrates multiple scattering models and advanced spin analysis

Abstract

We describe the physics and computational power of GRANIITTI Monte Carlo event generator, a new fully multithreaded engine designed for high energy diffraction, written in modern C++. The emphasis is especially on the low-mass domain of central exclusive processes of the S-matrix, where exotic QCD phenomena such as glueballs are expected and holographic dualities with gravity may be tested. The generator includes photon-photon, photon-pomeron, pomeron-pomeron, Durham QCD model and Tensor pomeron model type scattering amplitudes and advanced spin analysis tools. The generator combines a full parametric resonance spectrum with continuum interference and forward + central spin correlations together with event-by-event eikonal screening loop and forward proton excitation kinematics. We demonstrate the state-of-the-art capabilities and show how the enigmatic `glueball filter' observable is driven by spin polarization.