Electroweak phase transition

A thermal change in the electroweak Higgs sector as the early Universe cools. Its order and strength depend on the particle content, couplings and effective description. A polynomial landau free energy is a simplified model and does not, by itself, establish a model-independent Higgs-mass bound.

If $\lambda /a=x=m_H^2/m_0^2$ and $c/a=A+x$, then $\gamma =[72{\pi }^{2}x(A+x){]}^{-1}$ and ${\varphi }^{\ast }/T^{\ast }=(6\pi x{)}^{-1}$. Requiring both $\gamma <1$ and ${\varphi }^{\ast }>T^{\ast }$ gives $x_{-}<x<1/(6\pi )$, where $x_{-}=[-A+\sqrt{A^2+1/(18{\pi }^2)}]/2$. This is an open interval for the specified model. Failing the strength condition does not alone eliminate its first-order jump.