Exotic Higgs boson decays and the electroweak phase transition
Jonathan Kozaczuk (Department of Physics, University of California, San Diego, La Jolla, California 92093, USA, Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA, Department of Physics, University of Illinois, Urbana, Illinois 61801, USA); Michael J. Ramsey-Musolf (Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA, Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA, Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 China); Jessie Shelton (Department of Physics, University of Illinois, Urbana, Illinois 61801, USA)
Light new physics weakly coupled to the Higgs can induce a strong first-order electroweak phase transition (EWPT). Here, we argue that scenarios in which the EWPT is driven first-order by a light scalar with mass between and small mixing with the Higgs will be conclusively probed by the high-luminosity LHC and future Higgs factories. Our arguments are based on analytic and numerical studies of the finite-temperature effective potential and provide a well-motivated target for exotic Higgs decay searches at the LHC and future lepton colliders.
