Search for Sphalerons in Proton-Proton Collisions

TL;DR

This paper investigates the potential for detecting sphaleron-induced transitions in high-energy proton-proton collisions at the LHC and future colliders, building on theoretical predictions and simulating experimental signatures.

Contribution

It combines theoretical calculations of sphaleron transition rates with collider simulations to propose experimental search strategies and constraints at the LHC.

Findings

Sphaleron transition rates increase with collision energy, with large uncertainties.

LHC black hole searches can effectively detect sphaleron-induced final states.

Current data constrains sphaleron transition rates, especially at a 9 TeV barrier height.

Abstract

In a recent paper, Tye and Wong (TW) have argued that sphaleron-induced transitions in high-energy proton-proton collisions should be enhanced compared to previous calculations, based on a construction of a Bloch wave function in the periodic sphaleron potential and the corresponding pass band structure. Here we convolute the calculations of TW with parton distribution functions and simulations of final states to explore the signatures of sphaleron transitions at the LHC and possible future colliders. We calculate the increase of sphaleron transition rates in proton-proton collisions at centre-of-mass energies of 13/14/33/100 TeV for different sphaleron barrier heights, while recognising that the rates have large overall uncertainties. We use a simulation to show that LHC searches for microscopic black holes should have good efficiency for detecting sphaleron-induced final states, and discuss their experimental signatures and observability in Run 2 of the LHC and beyond. We recast the early ATLAS Run-2 search for microscopic black holes to constrain the rate of sphaleron transitions at 13 TeV, deriving a significant limit on the sphaleron transition rate for the nominal sphaleron barrier height of 9 TeV.