Stepping into electroweak symmetry breaking: Phase transitions and Higgs phenomenology
We study the dynamics of electroweak symmetry breaking in an extension of the Standard Model where the Higgs sector is augmented by the addition of a real (Y=0) isospin triplet. We show that this scenario exhibits a novel, two-step electroweak phase transition, wherein the first step provides the strongly first-order transition as required for electroweak baryogenesis, followed by a second step to the Standard Model Higgs phase that also admits a cold dark matter candidate. We analyze the constraints on this scenario from recent results obtained at the Large Hadron Collider for the Higgs diphoton decay channel. We argue that this two-step scenario can be generalized to extensions of the Standard Model with additional higher-dimensional scalar multiplets that may yield realistic baryogenesis dynamics.
Additional Information© 2013 American Physical Society. Received 12 March 2013; published 9 August 2013. The authors thank Max Wainwright for helpful correspondence regarding the CosmoTransitions software used for part of this work. H. P. also thanks Andrew Long for interesting discussions. This work was supported in part by U.S. Department of Energy Contract No. DE-FG02-08ER41531 and by the Wisconsin Alumni Research Foundation.
Published - PhysRevD.88.035013.pdf
Submitted - 1212.5652v1.pdf