2,048 research outputs found
Some Two-Loop Corrections to the Finite Temperature Effective Potential in the Electroweak Theory
Perturbation theory at finite temperature suffers from well-known infrared
problems. In the standard model, as a result, one cannot calculate the
effective potential for arbitrarily small values of , the Higgs
expectation value. Because the Higgs field is now known not to be extremely
light, it is necessary to determine whether perturbation theory is a reliable
guide to properties of the weak phase transition. In this note, we evaluate the
most singular contributions to the potential at two loops as well as the
leading strong interaction contributions. Above the critical temperature, the
strong interaction corrections are reasonably small, while the weak corrections
are about 10\%, even for rather small values of the Higgs field. At the
critical temperature, the weak corrections have a more substantial effect,
rendering the transition significantly more first order, but not significantly
changing the upper bound on the Higgs mass required for baryogenesis.Comment: 13 pages, figures available on request, SCIPP 92/4
On the High Phase Transition in the Gauged Higgs Model
We study the effective field theory of a weakly coupled 3+1d gauged
type model at high temperature. Our model has real scalars
( complex Higgs doublets) and a gauge group which is spontaneously
broken by a nonzero scalar field at zero temperature.
We find, for sufficiently large , that the transition from the high
temperature symmetry restoring phase to the low temperature phase can be either
first order or second order depending on the ratio of the gauge coupling to the
scalar self coupling.Comment: 16 pages. 1 Figure, not include
Quantum scale invariance, cosmological constant and hierarchy problem
We construct a class of theories which are scale invariant on quantum level
in all orders of perturbation theory. In a subclass of these models scale
invariance is spontaneously broken, leading to the existence of a massless
dilaton. The applications of these results to the problem of stability of the
electroweak scale against quantum corrections, to the cosmological constant
problem and to dark energy are discussed.Comment: 6 pages, replaced with journal versio
Strong Sphalerons and Electroweak Baryogenesis
We analyze the spontaneous baryogenesis and charge transport mechanisms
suggested by Cohen, Kaplan and Nelson for baryon asymmetry generation in
extended versions of electroweak theory. We find that accounting for
non-perturbative chirality-breaking transitions due to strong sphalerons
reduces the baryonic asymmetry by the factor or ,
provided those processes are in thermal equilibrium.Comment: CERN-TH.7080/9
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