We study the finite-temperature electroweak phase transition of the minimal standard model within the four-dimensional SU(2) gauge-Higgs model. Monte Carlo simulations are performed for intermediate values of the Higgs boson mass in the range $50 lesssim M_H lesssim 100$GeV on a lattice with the temporal size $N_t=2$. The order of the transition is systematically examined using finite-size scaling methods. Behavior of the interface tension and the latent heat for an increasing Higgs boson mass is also investigated. Our results suggest that the first-order transition terminates around $M_H sim 80$GeV.
We study the finite-temperature phase transition of the four-dimensional SU(2) gauge-Higgs model for intermediate values of the Higgs boson mass in the range $50 lsim m_H lsim 100$GeV on a lattice with the temporal lattice size $N_t=2$. The order of the transition is systematically examined using finite size scaling methods. Behavior of the interface tension and the latent heat for an increasing Higgs boson mass is also investigated.
We study the electroweak phase transition by lattice simulations of an effective 3-dimensional theory, for a Higgs mass of about $35 GeV$. In the broken symmetry phase our results on masses and the Higgs condensate are consistent with 2-loop perturbative results. However, we find a non-perturbative lowering of the transition temperature, similar to the one previously found at $m_H = 80 GeV$. For the symmetric phase, bound state masses and the static force are determined and compared with results for pure $SU(2)$ theory.
Using a variation of Lueschers geometric charge definition for SU(2) lattice gauge theory, we have managed to give a geometric expression for its Chern-Simons ter. From this definition we have checked the periodic structure. we determined the Chern-Simons density for symmetric and asymmetric lattices near the critical region in the SU(2) Higgs model. The data indicate that tunneling is increased at high temperature.
The pressure of QCD admits at high temperatures a factorization into purely perturbative contributions from hard thermal momenta, and slowly convergent as well as non-perturbative contributions from soft thermal momenta. The latter can be related to various effective gluon condensates in a dimensionally reduced effective field theory, and measured there through lattice simulations. Practical measurements of one of the relevant condensates have suffered, however, from difficulties in extrapolating convincingly to the continuum limit. In order to gain insight on this problem, we employ Numerical Stochastic Perturbation Theory to estimate the problematic condensate up to 4-loop order in lattice perturbation theory. Our results seem to confirm the presence of large discretization effects, going like $aln(1/a)$, where $a$ is the lattice spacing. For definite conclusions, however, it would be helpful to repeat the corresponding part of our study with standard lattice perturbation theory techniques.
We consider a non-Abelian dark SU(2)$_{rm D}$ model where the dark sector couples to the Standard Model (SM) through a Higgs portal. We investigate two different scenarios of the dark sector scalars with $Z_2$ symmetry, with Higgs portal interactions that can introduce mixing between the SM Higgs boson and the SM singlet scalars in the dark sector. We utilize the existing collider results of the Higgs signal rate, direct heavy Higgs searches, and electroweak precision observables to constrain the model parameters. The $text{SU(2)}_{text{D}}$ partially breaks into $text{U(1)}_{text{D}}$ gauge group by the scalar sector. The resulting two stable massive dark gauge bosons and pseudo-Goldstone bosons can be viable cold dark matter candidates, while the massless gauge boson from the unbroken $text{U(1)}_{text{D}}$ subgroup is a dark radiation and can introduce long-range attractive dark matter (DM) self-interaction, which can alleviate the small-scale structure issues. We study in detail the pattern of strong first-order phase transition and gravitational wave (GW) production triggered by the dark sector symmetry breaking, and further evaluate the signal-to-noise ratio for several proposed space interferometer missions. We conclude that the rich physics in the dark sector may be observable with the current and future measurements at colliders, DM experiments, and GW interferometers.