2,494 research outputs found
Real time simulations and the electroweak phase transition
We review recent developments in real-time simulations of SU(2)-Higgs theory
near the electroweak transition and related topics.Comment: 6 pages, latex, 4 figures; to appear in the proceedings of LATTICE
'9
Cold Electroweak Baryogenesis
We present arguments that the CKM CP-violation in the standard model may be
sufficient for the generation of the baryon asymmetry, if the electroweak
transition in the early universe was of the cold, tachyonic, type after
electroweak-scale inflation. A model implementing this is described which
complies with the CMB constraints and which is falsifiable with the LHC.
Numerical simulations of the tachyonic transition with an effective CP-bias
indicate that the observed baryon asymmetry can be generated this way.Comment: 10 pages, 4 figures, presented at Strong and ElectroWeak Matter 200
Simulations in Early Universe Theory
We give an impression of the type of results that have been obtained with
numerical lattice simulations of field theory in the early universe.Comment: 19 pages, contribution to Lattice 200
Classical issues in electroweak baryogenesis
In one scenario of baryogenesis, the matter-antimatter asymmetry was
generated in the early universe during a cold electroweak transition. We model
this transition by changing the sign of the effective mass-squared parameter of
the Higgs field from positive to negative. The resulting `tachyonic'
instability leads to a rapid growth of occupation numbers, such that a
classical approximation can be made in computing subsequent developments in
real time.
We solve the classical equations of motion in the SU(2)-Higgs model under the
influence of effective CP-violation. The resulting baryon asymmetry follows
from the generated Chern-Simons number using the anomaly equation. The
`classical' difficulties with lattice implementations of these observables are
avoided here because the fields are smooth on the lattice scale.Comment: Proceedings Lattice 2003 (Higgs), 3 pages; added reference
Simulations of Cold Electroweak Baryogenesis: Dependence on Higgs mass and strength of CP-violation
Cold electroweak baryogenesis was proposed as a scenario to bypass generic
problems of electroweak baryogenesis within the Standard Model. In this
scenario, baryogenesis takes place during an electroweak symmetry breaking
transition, which is also responsible for preheating after inflation. In the
simplest modelling of the scenario, only two parameters remain undetermined:
The Higgs mass and the strength of CP violation. Using full real-time lattice
simulations, we compute the dependence of the asymmetry on these parameters.Comment: 14 pages, 13 figure
Chern-Simons Diffusion Rate near the Electroweak Phase Transition for
The rate of -violation in the standard model at finite temperature is
closely related to the diffusion rate of Chern-Simons number. We
compute this rate for in the classical approximation in an
effective SU(2)-Higgs model, using Krasnitz's algorithm. The parameters in the
effective hamiltonian are determined by comparison with dimensional reduction.
In the high temperature phase we find ,
neglecting a finite renormalization. In the low temperature phase near the
transition we find the rate to be much larger than might be expected from
previous analytic calculations based on the sphaleron.Comment: 23 pages, 8 Postscript figures, uses epsf.st
No strong coupling regime in the fermion-Higgs sector of the standard model
We present results for the renormalized quartic self-coupling \lm_R and the
renormalized Yukawa coupling in a fermion-Higgs model with two SU(2)
doublets, indicating that these couplings are not very strong.Comment: 4 pages, 4 postscript figures (appended), ITFA-92-32, HLRZ-92-92,
UCSD/PTH 92-43, Contribution to the Conference Lattice'9
Chern-Simons number asymmetry from CP violation at electroweak tachyonic preheating
We consider the creation of non-zero Chern-Simons number in a model of the
early Universe, where the Higgs field experiences a fast quench at the end of
inflation and subsequently rolls down its potential barrier. Neglecting the
expansion, we perform numerical lattice simulations in the Abelian Higgs model
in 1+1 dimensions with an added phenomenological C and P violating term during
this stage of so-called tachyonic preheating. The results suggest that even the
sign of the Chern-Simons and thus baryon number is dependent on the ratio of
the Higgs to W mass. We also discuss the appropriate choice of vacuum initial
conditions for classical simulations.Comment: 24 pages, 17 figures, added references, published versio
- âŠ