Is There a Hot Electroweak Phase Transition at $m_H\gsim m_W$?

TL;DR

Non-perturbative evidence is provided for the fact that there is no hot electroweak phase transition at large Higgs masses, and the line of first order phase transitions separating the symmetric and broken phases at small $m_H$ has an end point.

Abstract

We provide non-perturbative evidence for the fact that there is no hot electroweak phase transition at large Higgs masses, $m_H = 95$, 120 and 180 GeV. This means that the line of first order phase transitions separating the symmetric and broken phases at small $m_H$ has an end point $m_{H,c}$. In the minimal standard electroweak theory 70 GeV $<m_{H,c}<$ 95 GeV and most likely $m_{H,c} \approx 80$ GeV. If the electroweak theory is weakly coupled and the Higgs boson is found to be heavier than the critical value (which depends on the theory in question), cosmological remnants from the electroweak epoch are improbable.

Figures (5)

• Figure 1: The schematical phase diagram for the SU(2) gauge-Higgs theory. Solid line is the phase transition and dashed lines indicate the metastability region.
• Figure 2: $\phi^\dagger\phi$ susceptibility at $m_H^*=120$ GeV plotted as a function of $T^*$ for lattices of various sizes. The lower panel shows in more detail the region near the maximum; the continuous lines with error bands result from multihistogram reweighting. The maximum values are plotted in Fig. 3.
• Figure 3: The maximum values $\chi_{\rm max}$ for different $m_H^*$ plotted as a function of $V$. The dashed lines are lines $\sim V,V^{1/2},V^0$.
• Figure 4: The scalar and vector mass dependence on the temperature for "small" Higgs masses, $m_H^*=60$ and $80$ GeV
• Figure 5: The scalar and vector mass dependence on the temperature for "large" Higgs masses, $m_H^*=120$ and $180$ GeV.