1,992 research outputs found
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
Particle Physics Models, Topological Defects and Electroweak Baryogenesis
We demonstrate the viability of electroweak baryogenesis scenarios in which
the necessary departure from equilibrium is realized by the evolution of a
network of topological defects. We consider several effective models of TeV
physics, each addressing a fundamental particle physics problem, and in which
the conditions necessary for defect-mediated electroweak baryogenesis are
naturally satisfied. In each case we compare the strength of the model with
that expected from scenarios in which baryogenesis proceeds with the
propagation of critical bubbles.Comment: 12 pages, LaTeX, no figure
Diffusion Enhances Spontaneous Electroweak Baryogenesis
We include the effects of diffusion in the electroweak spontaneous
baryogenesis scenario and show that it can greatly enhance the resultant baryon
density, by as much as a factor of over previous
estimates. Furthermore, the baryon density produced is rather insensitive to
parameters characterizing the first order weak phase transition, such as the
width and propagation velocity of the phase boundary.Comment: 15 pages, uses harvmac and epsf macro
Dynamical Breaking of CPT Symmetry in Defect Networks and Baryogenesis
Based on a study of {\it charge,} (C), {\it parity} (P) and {\it time
reversal} (T) symmetries we show how a CP violating network of defects in the
early Universe may bias baryon number production. A static network, even though
it violates CP, respects CPT and hence does not bias baryon number production.
On the other hand, the {\it ordering dynamics\/} of defects in a network,
governed by the interplay of string tension, friction, inertia and the
expansion of the Universe, results in the dynamical breakdown of CPT symmetry
and may lead to a net baryon number production.Comment: 5 pages, LaTeX with prl macros, no figure
The image of the Jew in James Joyce\u27s Ulysses
Since the beginning of English literature, the Jew has been portrayed as a villain. Edgar Rosenberg and Montague Frank Madder most affirmed the conviction in each of their studies of the Jew in English literature. However, the conclusion that the Jew is still portrayed as a villain is invalid because the image has changed. It is my intention to examine this change, focusing particularly on the character of Leopold Bloom in James Joyce \u27s Ulysses
A New Source for Electroweak Baryogenesis in the MSSM
One of the most experimentally testable explanations for the origin of the
baryon asymmetry of the universe is that it was created during the electroweak
phase transition, in the minimal supersymmetric standard model. Previous
efforts have focused on the current for the difference of the two Higgsino
fields, , as the source of biasing sphalerons to create the baryon
asymmetry. We point out that the current for the orthogonal linear combination,
, is larger by several orders of magnitude. Although this increases
the efficiency of electroweak baryogenesis, we nevertheless find that large
CP-violating angles are required to get a large enough baryon
asymmetry.Comment: 4 pages, 2 figures; numerical error corrected, which implies that
large CP violation is needed to get observed baryon asymmetry. We improved
solution of diffusion equations, and computed more accurate values for
diffusion coefficient and damping rate
Quark Diffusion and Baryogenesis at the Electroweak Phase Transition
Baryogenesis at the electroweak phase transition may take place through
CP-violating reflections of quarks from expanding bubbles of the broken
symmetry phase. We formulate and approximately solve the transport equations
for the reflected quark asymmetries. The results are comparable to a previous
Monte Carlo calculation and allow for analytic estimates of the baryon
asymmetry when the bubble walls have a small velocity. Our method
predicts no velocity-dependence for in the small limit, unlike
results obtained from a simplified treatment based on the diffusion equation.Comment: 11pp, 2 latex-generated figures using bezier.sty (included),
UMN-TH-1259-94. Errors corrected (suppression due to finite wall thickness is
reduced), explanations expanded (especially concerning the Fokker-Planck
approximation of the collision term), *NEW DISCUSSION* of the different
velocity dependence predicted by Boltzmann equation versus the diffusion
equation. To appear in Phys. Lett.
Neutral Heavy Leptons and Electroweak Baryogenesis
We investigate the possibility that baryogenesis occurs during the weak phase
transition in a minimal extension of the Standard Model which contains extra
neutral leptons and conserves total lepton number. The necessary CP-violating
phases appear in the leptonic Yukawa couplings. We compute the CP-asymmetries
in both the neutral and the charged lepton fluxes reflected on the bubble wall.
Using present experimental bounds on the mixing angles and Standard Model
estimates for the parameters related to the scalar potential, we conclude that
it seems unlikely to produce the observed baryon to entropy ratio within this
type of models. We comment on the possibility that the constraints on the
mixings might be naturally relaxed due to small finite temperature effects.Comment: 21 pages (4 Figures
Electroweak Baryogenesis: Concrete in a SUSY Model with a Gauge Singlet
SUSY models with a gauge singlet easily allow for a strong first order
electroweak phase transition (EWPT) if the vevs of the singlet and Higgs fields
are of comparable size. We discuss the profile of the stationary expanding
bubble wall and CP-violation in the effective potential, in particular
transitional CP-violation inside the bubble wall during the EWPT. The
dispersion relations for charginos contain CP-violating terms in the WKB
approximation. These enter as source terms in the Boltzmann equations for the
(particle--antiparticle) chemical potentials and fuel the creation of a baryon
asymmetry through the weak sphaleron in the hot phase. This is worked out for
concrete parameters.Comment: 46 pages, LaTeX, 11 figures, discussion of source terms and transport
equations modified, version to appear in Nucl. Phys.
Mirror Writing and a Dissociative Identity Disorder
Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Examâmirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder
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