# Electroweak instantons/sphalerons at VLHC?

## TL;DR

This paper evaluates the potential observability of electroweak instanton-induced B+L violation processes at future high-energy colliders like VLHC, finding them likely unobservable within conservative parameters but possibly detectable at higher energies.

## Contribution

It provides a state-of-the-art calculation of QFD instanton cross-sections at energies relevant for future colliders, incorporating recent lattice and experimental insights.

## Key findings

- Cross-sections are unobservably small within conservative limits.
- Extrapolation suggests possible observability at VLHC energies.
- Results are consistent with current lattice and HERA data.

## Abstract

There is a close analogy between electroweak instanton-induced baryon plus lepton number (B+L) violating processes in Quantum Flavor Dynamics (QFD) and hard QCD instanton-induced chirality violating processes in deep-inelastic scattering. In view of the recent information about the latter both from lattice simulations and from the H1 experiment at HERA, it seems worthwhile to reconsider electroweak B+L violation at high energies. We present a state of the art evaluation of QFD instanton-induced parton-parton cross-sections, as relevant at future high energy colliders in the hundreds of TeV regime, such as the projected Very Large Hadron Collider (VLHC). We find that the cross-sections are unobservably small in a conservative fiducial kinematical region inferred from the above mentioned QFD--QCD analogy. An extrapolation -- still compatible with lattice results and HERA -- beyond this conservative limit indicates possible observability at VLHC.