Generation of baryon inhomogeneities in the electroweak phase transition

Mégevand, Ariel; Astorga, Francisco

doi:10.1103/physrevd.71.023502

Cited by 27 publications

(68 citation statements)

References 73 publications

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“…However, as noticed in Ref. [53], the effect of the velocity variation on the BAU is likely to be an O(1) one effect and should not modify the main conclusions of this paper. …”

Section: Cp-violating Sources and Baryogenesismentioning

confidence: 82%

Electroweak baryogenesis and new TeV fermions

et al. 2005

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New fermions, strongly coupled to the Standard Model Higgs boson, provide a well motivated extension of the Standard Model (SM). In this work we show that, once new physics at heavier scales is added to stabilize the Higgs potential, such an extension of the SM can strengthen the first order electroweak phase transition and make the electroweak baryogenesis mechanism feasible. We propose a SM extension with TeV Higgsinos, Winos and Binos that satisfy the following properties: a) The electroweak phase transition is strong enough to avoid sphaleron erasure in the broken phase for values of the Higgs mass m H < ∼ 300 GeV; b) It provides large CP-violating currents that lead to the observed baryon asymmetry of the Universe for natural values of the CP-violating phase; c) It also provides a natural Dark Matter candidate that can reproduce the observed dark matter density; d) It is consistent with electroweak precision measurements; e) It may arise from a softly broken supersymmetric theory with an extra (asymptotically free) gauge sector; f ) It may be tested by electron electric dipole moment experiments in the near future.

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“…However, as noticed in Ref. [53], the effect of the velocity variation on the BAU is likely to be an O(1) one effect and should not modify the main conclusions of this paper. …”

Section: Cp-violating Sources and Baryogenesismentioning

confidence: 82%

Electroweak baryogenesis and new TeV fermions

et al. 2005

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“…This is a reasonable approximation if the temperature only varies in a small range about T c , which is true for most phase transitions. 5 In contrast, since the equation of state may depart significantly form the bag EOS (particularly in the '−' phase), the values of c ± may depart from the bag value c s = 1/ √ 3. For the model (10) we have…”

Section: The Equation Of Statementioning

confidence: 91%

Hydrodynamics of phase transition fronts and the speed of sound in the plasma

Leitao

Mégevand

2015

Nuclear Physics B

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The growth of bubbles in cosmological first-order phase transitions involves nontrivial hydrodynamics. For that reason, the study of the propagation of phase transition fronts often requires several approximations. A frequently used approximation consists in describing the two phases as being composed only of radiation and vacuum energy (the so-called bag equation of state). We show that, in realistic models, the speed of sound in the low-temperature phase is generally smaller than that of radiation, and we study the hydrodynamics in such a situation. We find in particular that a new kind of hydrodynamical solution may be possible, which does not arise in the bag model. We obtain analytic results for the efficiency of the transfer of latent heat to bulk motions of the plasma, as a function of the speed of sound in each phase.

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“…Various theories of cosmic phase transitions may lead to the formation of baryon inhomogeneous regions, for example during a first order quark hadron phase transition [15,16,17,18,19,20,21,22,23] or during the electroweak phase transition [24,25,26,27,28].…”

Section: Introductionmentioning

confidence: 99%

“…Inhomogeneities can have planar, cylindrical or spherical symmetry [26,27,29,30,31]. The evolution of baryon inhomogeneous regions can be modelled using an IBBN code [6, 19, 20, [42].…”

Section: Introductionmentioning

confidence: 99%

Inhomogeneous big bang nucleosynthesis revisited

2006

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We reanalyze the allowed parameters for inhomogeneous big bang nucleosynthesis in light of the WMAP constraints on the baryon-to-photon ratio η and a recent measurement which has set the neutron lifetime to be 878.5 ± 0.7 ± 0.3 seconds. For a set baryon-to-photon ratio η the new lifetime reduces the mass fraction of 4 He by 0.0015 but does not significantly change the abundances of other isotopes. This enlarges the region of concordance between 4 He and deuterium in the parameter space of η and the IBBN distance scale r i . The 7 Li abundance can be brought into concordance with observed 4 He and deuterium abundances by using depletion factors as high as 9.3. The WMAP constraints, however, severely limit the allowed comoving (T = 100 GK) inhomogeneity distance scale to r i ≈ (1.3 − 2.6) × 10 5 cm. Big bang nucleosynthesis (BBN) plays a crucial role in constraining our views on the universe. It is essentially the only probe of physics in the early radiation dominated epoch during the interval from ∼ 1−10 4 sec. Moreover, big bang cosmology is currently undergoing rapid evolution based upon high precision determinations of cosmological parameters and improved input physics. Thus, it is important to scrutinize all possible variants of BBN and understand the constraints which modern observations place upon their parameters. This paper summarizes the current status on one such important variant of the big bang, namely one in which the baryons are spatially inhomogeneously distributed during the epoch of nucleosynthesis. We consider the constraints from WMAP and the latest observed elemental abundances and include recent measurements of thermonuclear reaction rates and the neutron lifetime. We show, that although the parameter space for inhomogeneous big bang nucleosynthesis (IBBN) is significantly limited, interesting regions remain and this paradigm continues to be a viable possibility for the early universe. II. BACKGROUNDAt a high temperature in the early universe, e.g. T ∼ 100 GK (the corresponding age of the universe is ∼ 0.01 seconds) baryons mainly exist in the form of free neutrons and protons.During this epoch neutrons and protons are rapidly interconverted via the following weak reactions [1,2,3] n + ν e ↔ p + e − n + e + ↔ p +ν e n ↔ p + e − +ν e .As long as these reactions are in thermal equilibrium the ratio of neutrons to protons is given by (n/p) = exp[−∆m/kT ] where ∆m is the mass difference between neutrons and protons. When the universe cools to a temperature T = 13 GK these weak reactions fall out of equilibrium. The n/p ratio after that time decreases only due to neutron decay.When the universe cools to a temperature T ≈ 0.9 GK the nuclear reaction n + p ↔ d + γ falls out of nuclear statistical equilibrium. Deuterium production becomes significant, 3 leading to the synthesis of increasingly heavier nuclei through a network of nuclear reactions and weak decays. When nearly all free neutrons are incorporated into 4 He nuclei, 4 He production virtually stops. The final mass fraction can be ap...

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Generation of baryon inhomogeneities in the electroweak phase transition

Cited by 27 publications

References 73 publications

Electroweak baryogenesis and new TeV fermions

Electroweak baryogenesis and new TeV fermions

Hydrodynamics of phase transition fronts and the speed of sound in the plasma

Inhomogeneous big bang nucleosynthesis revisited

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