On the phenomenology of sphaleron-induced processes at the LHC and beyond

Abstract

Abstract We investigate the phenomenological aspects of non-perturbative baryon- and lepton-number-violating processes at hadron colliders. Such processes, induced by instan- ton/sphaleron configurations of the electroweak gauge fields, are believed to play a crucial role in the generation of baryon asymmetry in the early Universe at finite temperature. On the other hand, at colliders (that represent the zero-temperature high-energy regime) the rate and observability of such processes are still under debate. Motivated by current the- oretical considerations, we construct a modern event generator within the general-purpose Herwig Monte Carlo framework, that aims to capture the most relevant features of the dominant processes. We perform a detailed phenomenological analysis focussing on the Large Hadron Collider, at 13 TeV proton-proton centre-of-mass energy, a potential high- energy upgrade at 27 TeV and the proposed Future Circular Collider (FCC-hh) at 100 TeV. We derive constraints on the expected rates for various parametrisations of our model. We find that all three colliders are capable of providing meaningful information on the nature of instanton/sphaleron-induced processes at various energy scales.