A Search for Sphalerons at the LHC

by Cameron Bravo (University of California Los Angeles (US))

Tuesday 11 Sept 2018, 12:30 → 13:30 US/Pacific

Other Institutes

Sphaleron and instanton solutions of the Standard Model provide violation of baryon and lepton numbers and could lead to spectacular events at the LHC or future colliders. Certain models of new physics can also lead to sphaleron-like vacuum transitions. This nonperturbative physics could be relevant to the generation of the matter-antimatter asymmetry of the universe. I have developed BaryoGEN, an event generator that facilitates the exploration of sphaleron-like transitions in proton-proton collisions with minimal assumptions. BaryoGEN outputs standard Les Houches Event files that can be processed by PYTHIA. The new generator is used to perform the first dedicated experimental search for sphaleron production in proton-proton collisions using the 2016 CMS dataset. A limit on the pre-exponential factor for sphaleron production is set at 0.021 for the nominal transition energy of 9 TeV, an order of magnitude below the previous limit set by a phenomenological recasting of an ATLAS black hole search. Possibilities for the future of searching for electroweak sphaleron-like transitions are discussed.

lhcSphalerons.pdf