The electroweak phase transition: a collider target
Determining the thermal history of electroweak symmetry breaking (EWSB) is an important challenge for particle physics and cosmology. Lattice simulations indicate that EWSB in the Standard Model (SM) occurs through a crossover transition, while the presence of new physics beyond the SM could alter this thermal history. The occurrence of a first order EWSB transition would be particularly interesting, providing the needed pre-conditions for generation of the cosmic matter-antimatter asymmetry and sources for potentially observable gravitational radiation. I provide simple, generic arguments that if such an alternate thermal history exists, the new particles involved cannot be too heavy with respect to the SM electroweak temperature, nor can they interact too feebly with the SM Higgs boson. These arguments do not rely on the decoupling limit. I derive corresponding quantitative expectations for masses and interaction strengths which imply that their effects could in principle be observed (or ruled out) by prospective next generation high energy colliders. The simple, generic arguments provide a quantitative, parametric understanding of results obtained in a wide range of explicit model studies; relate them explicitly to the electroweak temperature; and delineate broad contours of collider phenomenology pertaining to a non-standard history of EWSB.
Additional Information© 2020 The Authors. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. Article funded by SCOAP3. Received 16 April 2020. Revised 02 July 2020. Accepted 17 August 2020. Published 30 September 2020. I am grateful to D. Curtin, J. Gao, J. Kozaczuk, M. Mangano, P. Meade, L. Niemi, E. Senaha, J. Shelton, M. Spannowsky, S. Su, and T.V.I. Tenkanen for several useful conversations during the course of this work. I am also indebted to G. Li, J.C. Vasquez, and J. Zhou who performed several cross checks of some of the expressions appearing in this paper and for assistance with numerical evaluation of the pp cross sections. This work was supported in part under U.S. Department of Energy contract DE-SC0011095 and National Science Foundation of China grant No. 19Z103010239.
Accepted Version - 1912.07189.pdf