Physical Sciences

Under the assumption that the current epoch of the Universe is not special, i.e., is not the final state of a long history of processes in particle physics, the cosmological fate of SU(3)C×U(1)EM is investigated. Spontaneous symmetry breaking of U(1)EM at the temperature of the Universe today is carried out. The charged scalar field φEM which breaks the symmetry is found to be ruled out for the charge of the electron, q=e. Scalar fields with millicharges are viable and limits on their masses and charges are found to be q10-3e and mφEM10-5 eV. Furthermore, it is possible that U(1)EM has already been broken at temperatures higher than T=2.7 K given the nonzero limits on the mass of the photon. A photon mass of mγ=10-18 eV, the current upper limit, is found to require a spontaneous symmetry breaking scalar mass of mφEM∼10-13 eV with charge q=10-6e, well within the allowed parameter space of the model. Finally, the cosmological fate of the strong interaction is studied. SU(3)C is tested for complementarity in which the confinement phase of QCD+ colored scalars is equivalent to a spontaneously broken SU(3) gauge theory. If complementarity is not applicable, SU(3)C has multiple symmetry breaking paths with various final symmetry structures. The stability of the colored vacuum at finite temperature in this scenario is nonperturbative and a definitive statement on the fate of SU(3)C is left open. Cosmological implications for the metastability of the vacua - electromagnetic, color, and electroweak - are discussed.