Electroweak instantons/sphalerons at VLHC?

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.