The electro-weak phase transition at colliders: confronting theoretical uncertainties and complementary channels

We revisit the perturbative expansion at high temperature and investigate its convergence by inspecting the renormalisation scale dependence of the effective potential. Although at zero temperature the renormalisation group improved effective potential is scale independent at one-loop, we show how this breaks down at high temperature, due to the misalignment of loop and coupling expansions. Following this, we show how one can recover renormalisation scale independence at high temperature, and that it requires computations at two-loop order. We demonstrate how this resolves some of the huge theoretical uncertainties in the gravitational wave signal of first-order phase transitions, though uncertainties remain stemming from the computation of the bubble nucleation rate.

Section: (B) Bm2supporting

confidence: 89%

Section: Jhep06(2021)069mentioning

confidence: 99%

On the perturbative expansion at high temperature and implications for cosmological phase transitions

Gould

Tenkanen

2021

“…According to the SU (2) L quantum number of a given representation, the extended scalar could be classified as real or complex singlet, doublet, real or complex triplet, quadruplet, and so on. These new scalars usually affect the electroweak symmetry breaking pattern and in principle may catalyze a first order electroweak phase transition (EWPT) [13][14][15][16][17][18][19]. Furthermore, in some cases these scalars could provide the dark matter candidates [20][21][22][23][24][25][26][27][28][29][30][31] or mechanism for neutrino mass generation [32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Probing extended scalar sectors with precision e+e− → Zh and Higgs diphoton studies

Ramsey-Musolf

Zhou

2021

We compute the one-loop corrections to σ(e+e−→ Zh) arising from representative extended Standard Model scalar sector scenarios. According to the new scalar SU(2)L representations, we consider the inert doublet, real and complex triplet, quintuplet, and septuplet models. With the sub-percent level precision expected for prospective future e+e− collider measurements of σ(e+e−→ Zh), studies of the Higgsstrahlung process will probe extended scalar sector particle spectrum and interactions in a manner complementary to direct searches at the Large Hadron Collider and possible future pp colliders. We also compare with the sensitivity of future Higgs diphoton decay rate measurements. We find that the σ(e+e−→ Zh) and Γ(h → γγ) complementarity is particularly pronounced for the complex triplet model.

“…In the standard perturbative approach, the effective potential receives contributions from the tree-level potential, the one-loop Coleman-Weinberg correction and its finite-temperature counterpart, as well as Daisy resummations, which together leads to a gauge dependent result (see, e.g., refs. [119,120] for a study of the uncertainties with this approach). A gauge independent result nevertheless can still be obtained if only the leading order thermal correction at the high temperature is kept [121].…”

Section: Electroweak Phase Transitionmentioning

confidence: 99%

Electroweak phase transition with an SU(2) dark sector

Ghosh

Guo

Han

et al. 2021

We consider a non-Abelian dark SU(2)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 Z2 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 SU(2)D partially breaks into U(1)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 U(1)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.