How to discover QCD Instantons at the LHC

Abstract

The Standard Model of particle physics predicts the existence of quantum tunnelling processes across topological inequivalent vacua, commonly known as Instantons. In Quantum Chromodynamics, these Instantons play a fundamental role in explaining much of the theory long-distance behaviour. However, they have not yet been observed experimentally. Their direct observation would mark a breakthrough in modern particle physics, shedding light on our fundamental understanding of the non perturbative dynamics in the Standard Model. Recently, new calculations for QCD Instanton processes in proton–proton collisions became public, suggesting sizeable cross sections as well as possible experimental signatures at the LHC. In this work, we explore possible analysis strategies for the LHC experiments to discover small-size QCD Instanton induced processes. Moreover, we derive a first limit on the Instanton production cross section using published data of Minimum Bias processes at s=13 TeV at the LHC.