Probing QCD instantons using jet correlation observables in proton-proton collisions at the LHC

Abstract

Discovery of instantons in colliders will provide experimental evidence for the topological properties of the QCD vacuum. In this work, we propose jet correlation observables that can unambiguously discriminate between instanton-induced processes and perturbative hard scattering events in $pp$ collisions at the LHC for a specific range of center-of-mass energies of the produced hadrons. By calculating the instanton sizes and their separations in 2+1 flavor QCD with physical quark masses, we provide a qualitative understanding of why the semiclassical methods reliably predict the cross-section of instanton-induced processes at the particular center-of-mass energies we are focusing on. Our proposal is directly applicable to future $ep$ measurements at the Electron-Ion Collider, offering a cleaner environment to probe instanton-induced processes.

v2: typos corrected and a few clarifications added. Accepted for publication in Phys. Lett. B

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