1,992 research outputs found

    CP Violation and the Baryonic Asymmetry of the Universe

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    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, ZZ 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

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    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

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    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 1/αw4∌1061/\alpha_w^4 \sim 10^6 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

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    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

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    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

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    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, H1−H2H_1-H_2, as the source of biasing sphalerons to create the baryon asymmetry. We point out that the current for the orthogonal linear combination, H1+H2H_1+H_2, is larger by several orders of magnitude. Although this increases the efficiency of electroweak baryogenesis, we nevertheless find that large CP-violating angles ≄0.15\ge 0.15 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

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    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 ΔB\Delta B when the bubble walls have a small velocity. Our method predicts no velocity-dependence for ΔB\Delta B in the small vv 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

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    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

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    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

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    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 Exam—mirror 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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