112 research outputs found
Numerical Simulations and the Strength of the Electroweak Phase Transition
Numerical simulations are performed to study the finite temperature phase
transition in the SU(2) Higgs model on the lattice. The strength of the first
order phase transition is investigated by determining the latent heat and the
interface tension on lattices. The values of the Higgs boson mass
presently chosen are below 50 GeV. Our results are in qualitative agreement
with two-loop resummed perturbation theory.Comment: (Only a few minor changes compared to the original version.) 9 pages
and 2 figures, DESY-94-08
Numerical tests of the electroweak phase transition and thermodynamics of the electroweak plasma
The finite temperature phase transition in the SU(2) Higgs model at a Higgs
boson mass GeV is studied in numerical simulations on
four-dimensional lattices with time-like extensions up to . The effects
of the finite volume and finite lattice spacing on masses and couplings are
studied in detail. The errors due to uncertainties in the critical hopping
parameter are estimated. The thermodynamics of the electroweak plasma near the
phase transition is investigated by determining the relation between energy
density and pressure.Comment: latex2e, 32 pages, 11 figures with epsfig; A few comments and a new
table are adde
Symmetry Restoration in Hot SUSY
It is by now well known that symmetries may be broken at high temperature.
However,in renormalizable supersymmetric theories any internal symmetry gets
always restored. In nonrenormalizable theories the situation is far less
simple. We review here some recent work which seems to indicate that
renormalizability is not essential for the restoration of internal symmetries
in supersymmetry.Comment: 8 pages, revtex, no figures. Based on the talk given by G. Senjanovic
at SUSY96, University of Maryland, 1996. To appear in the Proceeding
On the scaling of the electroweak interface tension at finite temperature
We determine the interface tension of the finite-temperature electroweak
phase transition in a numerical investigation of the SU(2)--Higgs model on a
four-dimensional lattice with temporal extension . In this simulation
the chosen parameters correspond to a Higgs boson mass of about 16 GeV. As a
result the interface tension shows only small scaling violations in comparison
with previous studies for lattices. We also report on some experiences
with autocorrelations in the applied Monte Carlo simulations of two-phase
systems.Comment: 10 pages, latex2e, 7 Postscript figures, uses packages epsfig and
amssym
Plasma polarization in high gravity astrophysical objects
Macroscopic plasma polarization, which is created by gravitation and other
mass-acting (inertial) forces in massive astrophysical objects is under
discussion. Non-ideality effect due to strong Coulomb interaction of charged
particles is introduced into consideration as a new source of such
polarization. Simplified situation of totally equilibrium isothermal star
without relativistic effects and influence of magnetic field is considered. The
study is based on variational approach combined with "local density
approximation". It leads to two local forms of thermodynamic equilibrium
conditions: constancy for generalized (electro)chemical potentials and/or
conditions of equilibrium for the forces acting on each charged specie. New
"non-ideality potential" and "non-ideality force" appear naturally in this
consideration. Hypothetical sequences of gravitational, inertial and
non-ideality polarization on thermo- and hydrodynamics of massive astrophysical
objects are under discussion.Comment: 6 pages, no figures, 35 refs, Int. Conference "Physics of Non-Ideal
Plasmas" (PNP-13), Chernogolovka, September 2009, Russi
A Lattice Monte Carlo Study of the Hot Electroweak Phase Transition
We study the finite temperature electroweak phase transition with lattice
perturbation theory and Monte Carlo techniques. Dimensional reduction is used
to approximate the full four-dimensional SU(2) + a fundamental doublet Higgs
theory by an effective three-dimensional SU(2) + adjoint Higgs + fundamental
Higgs theory with coefficients depending on temperature via screening masses
and mass counterterms. Fermions contribute to the effective theory only via the
and dependence of the coefficients. For sufficiently small
lattices ( for = 35 GeV) the study of the one-loop lattice
effective potential shows the existence of the {\em second} order phase
transition even for the small Higgs masses. At the same time, a clear signal of
a {\em first order} phase transition is seen on the lattice simulations with a
transition temperature close to but less than the value determined from the
perturbative calculations. This indicates that the dynamics of the first order
electroweak phase transition depends strongly on non-perturbative effects and
is not exclusively related to the so-called term in the effective
potential.Comment: 15 pages, use latex+epsfig, includes 6 ps-figures, CERN-TH.6901/9
Kinetic energy density functionals from the Airy gas, with an application to the atomization kinetic energies of molecules
We construct and study several semilocal density functional approximations
for the positive Kohn-Sham kinetic energy density. These functionals fit the
kinetic energy density of the Airy gas and they can be accurate for integrated
kinetic energies of atoms, molecules, jellium clusters and jellium surfaces. We
find that these functionals are the most accurate ones for atomization kinetic
energies of molecules and for fragmentation of jellium clusters. We also report
that local and semilocal kinetic energy functionals can show "binding" when the
density of a spin unrestricted Kohn-Sham calculation is used.Comment: 7 pages, 7 figure
The electroweak phase transition at GeV from lattices
We study the finite-temperature electroweak phase transition by numerical
simulations of the four-dimensional SU(2)-Higgs model on anisotropic lattices
with temporal extension . The physically interesting parameter region of
Higgs masses near 80 GeV is reached, and recent results on some thermodynamic
quantities are presented.Comment: Poster presented by J. Heitger at LATTICE97, 3 pages, latex2e, 4
Postscript figures, uses packages epsfig and espcrc
On supersymmetry at high temperature
While it is possible to find examples of field theories with a spontaneously
broken symmetry at high temperature, in renormalizable supersymmetric models
any internal symmetry gets always restored. Recently, a counterexample was
suggested in the context of nonrenormalizable supersymmetric theories. We show
that non negligible higher loop effects actually restore the symmetry, without
compromising the validity of perturbation theory. We give some arguments as to
why the proposed mechanism should not work in general.Comment: Latex, 8 pages, one figur
CP Violation and the Baryonic Asymmetry of the Universe
The physics of electroweak baryogenesis is described with the aim of making
the essentials clear to non-experts. Several models for the source of the
necessary CP violation are discussed: CKM phases as in the minimal standard
model, general two higgs doublet models, the supersymmetric standard model,
condensates, and the singlet majoron model. In a more technical section, a
strategy is introduced for consistently treating quark dynamics in the
neighborhood of the bubble wall, where both local and non-local interactions
are important. This provides a method for deciding whether gluonic corrections
wash out the elecroweak contribution to the baryonic asymmetry in the minimal
standard model.Comment: latex, 42pp, no figs. Invited talk at Trends in Astroparticle
Physics, Stockholm, Sept 1994
- …