arXiv subjects

J. Baacke

Publications and source records attributed to J. Baacke.

23 records · Page 2Linked to original sources

arXiv1994

The Fermion Determinant in External Scalar Fields: Exact Results and Large Mass Approximation

We present results for the fermion determinant in an external Yukawa-coupled scalar field, a quantity relevant to instanton and sphaleron transition rates as well as bubble nucleation occuring in the electroweak phase transition when the scalar field is identified with the Higgs field. We calculate the determinant exactly and find an approximation (essentialy of the gradient expansion type) that reproduces the exact results very well if the fermion mass $m_F$ becomes larger than the inverse of the size $R$ of the background field configuration. The results are given for 2, 3 and 4 Euclidean dimensions.

hep-ph↗

arXiv1994

Quantum fluctuations of the electroweak sphaleron: Erratum and Addendum

We correct an error in our treatment of the tadpole contribution to the fluctuation determinant of the sphaleron, and also a minor mistake in a previous estimate. Thereby the overall agreement between the two existing exact computations and their consistency with the estimate is improved considerably.

hep-th↗

arXiv1993

Quantum Fluctuations around the Electroweak Sphaleron

We present an analysis of the quantum fluctuations around the electroweak sphaleron and calculate the associated determinant which gives the 1--loop correction to the sphaleron transition rate. The calculation differs in various technical aspects from a previous analysis by Carson et al. so that it can be considered as independent. The numerical results differ also -- by several orders of magnitude -- from those of this previous analysis; we find that the sphaleron transition rate is much less suppressed than found previously.

hep-ph↗

arXiv1993

One-Loop Corrections to Bubble Nucleation Rate at Finite Temperature

We present an evaluation of the 1-loop prefactor in the lifetime of a metastable state which decays at finite temperature by bubble nucleation. Such a state is considered in one-component phi^4 model in three space dimensions. The calculation serves as a prototype application of a fast numerical method for evaluating the functional determinants that appear in semiclassical approximations.

hep-ph↗

arXiv1993

Quantum Corrections to the Electroweak Sphaleron Transition

We have performed a new exact evaluation of the fluctuation determinant $κ$ of the electroweak sphaleron with $Θ_W =0$. The results differ significantly from a previous calculation of this quantity by Carson et. al. . We find that $κ$ is of order 1 in units $(gv)^6$ while the previous results indicated a strong suppression of the sphaleron transition by this factor.

hep-ph↗