One interpretation of proton stability is the existence of extra-flat directions of the MSSM, in particular $u^{c}u^{c}d^{c}e^{c}$ and $QQQL$, where the operators lifting the potential are suppressed by a mass scale $Λ$ which is much larger than the Planck mass, $ Λ\gae 10^{26} \GeV$. Using D-term hybrid inflation as an example, we show that such flat directions can serve as the inflaton in SUSY inflation models. The resulting model is a minimal version of D-term inflation which requires the smallest number of additional fields. In the case where $Q$-balls form from the extra-flat direction condensate after inflation, successful Affleck-Dine baryogenesis is possible if the suppression mass scale is $\gae 10^{31}-10^{35} \GeV$. In this case the reheating temperature from $Q$-ball decay is in the range $3-100 \GeV$, while observable baryon isocurvature perturbations and non-thermal dark matter are possible. In the case of extra-flat directions with a large $t$ squark component, there no $Q$-ball formation and reheating is via conventional condensate decay. In this case the reheating temperature is in the range $1-100 \TeV$, naturally evading thermal gravitino overproduction while allowing sphaleron erasure of any large B-L asymmetry.
We study the implications for electroweak baryogenesis (EWB) within the minimal supersymmetric Standard Model (MSSM) of present and future searches for the permanent electric dipole moment (EDM) of the electron, for neutralino dark matter, and for supersymmetric particles at high energy colliders. We show that there exist regions of the MSSM parameter space that are consistent with both present two-loop EDM limits and the relic density and that allow for successful EWB through resonant chargino and neutralino processes at the electroweak phase transition. We also show that under certain condit…
We study electroweak baryogenesis and electric dipole moments in the presence of the two leading-order, non-renormalizable operators in the Higgs sector of the MSSM. Significant qualitative and quantitative differences from MSSM baryogenesis arise due to the presence of new CP-violating phases and to the relaxation of constraints on the supersymmetric spectrum (in particular, both stops can be light). We find: (1) spontaneous baryogenesis, driven by a change in the phase of the Higgs vevs across the bubble wall, becomes possible; (2) the top and stop CP-violating sources can become effective; …
We compare electroweak baryogenesis in the MSSM, nMSSM and NMSSM. We comment on the different sources of CP violation, the phase transition and constraints from EDM measurements.
We revisit the electroweak baryogenesis within the context of the minimal supersymmetric standard model (MSSM), studying its potential collider signatures. We find that this mechanism of baryogenesis does not give a new CP violating signal at the $B$-factories. The first circumstantial evidence may come from enhanced $B_s$ or $B_d$ mixing. If a light right-handed scalar top and Higgs are found as required, a linear collider represents the best possibility for confirming the scenario.
We study electric dipole moment bounds on CP-violating phases in the MSSM with special emphasis on the cancelation scenario. We find that in the range favored by electroweak baryogenesis ({\it i.e.,} $|μ|\simeq M_1$ or $|μ|\simeq M_2$), $\sin [θ_μ+θ_{M_1}]$ can be as large as ${\cal O}(1)$, even for slepton masses below 500 GeV. Such large values of the phases promise a successful electroweak baryogenesis. We also discuss the possibility of large CP-odd effects at a linear collider.
We review the baryogenesis scenario in the MSSM at the perturbative level and, in particular, the impact of two-loop corrections on the strength of the phase transition and the amount of generated baryon asymmetry. We confirm the baryogenesis window, where m_H is less than 115GeV, for m_Q less than a few GeV, and the right-handed stop mass is constrained in the region between 100GeV and the top mass. This scenario will be tested at LEP and Tevatron colliders.
We study the conditions for successful Affleck-Dine baryogenesis in generic inflation and supergravity scenarios, finding powerful restrictions on them. String-based SUGRA models are especially interesting since they are surprisingly suitable for the implementation not only of AD baryogenesis but also inflation itself, presenting a nice solution to the $η$--problem.
Taking the MSSM as an effective low-energy theory, with a cut-off scale of a few TeV, can make significant modifications to the predictions concerning the Higgs and stop sectors. We investigate the consequences of such a scenario for electroweak baryogenesis. We find that the window for MSSM baryogenesis is extended and, most important, can be made significantly more natural. Specifically, it is possible to have one stop lighter than the top and the other significantly lighter than TeV simultaneously with the Higgs mass above the LEP bound. In addition, various aspects concerning CP violation …
We show that, for all values of $Tan β$ and the light right-handed stop mass for which the electroweak phase transition is strong enough to avoid washout following electroweak baryogenesis, the electroweak vacuum is stable over the lifetime of the observed Universe. Cosmological stability of the electroweak vacuum is violated only if the light right-handed stop is lighter than 100-115GeV.
We have analyzed baryogenesis in the MSSM for the light stop scenario, where the phase transition is strong enough first order. We have found that enough baryon asymmetry can be generated provided that the phase of $μ$ be $\simgt$ 0.01. Constraints from the electric dipole moment of the neutron enforce the first and second generation squarks to have masses O(few) TeV
We discuss spontaneous baryogenesis in the warm inflation scenario. In contrast with standard inflation models, radiation always exists in the warm inflation scenario, and the inflaton must be directly coupled to it. Also, the transition to the post-inflationary radiation dominated phase is smooth and the entropy is not significantly increased at the end of the period of inflation. In addition, after the period of warm inflation ends, the inflaton does not oscillate coherently but slowly rolls. We show that as a consequence of these features of warm inflation, the scenario can well accommodate…
The thermal average of the Polyakov line is non-zero at high temperature. It has been suggested that its phase could be relevant for baryogenesis within the standard model, providing a source of spontaneously broken CP violation. This scenario suffers from a causal domain problem which cannot be cured by inflation: quantum fluctuations in de Sitter space overwhelm the periodicity of the potential.
We explore the implications of electroweak baryogenesis for future searches for permanent electric dipole moments in the context of the minimal supersymmetric extension of the Standard Model (MSSM). From a cosmological standpoint, we point out that regions of parameter space that over-produce relic lightest supersymmetric particles can be salvaged only by assuming a dilution of the particle relic density that makes it compatible with the dark matter density: this dilution must occur after dark matter freeze-out, which ordinarily takes place after electroweak baryogenesis, implying the same deg…
We present an analysis of the thermalization rate of Higgsinos and winos based on the imaginary part of the two-point Green function in the {\it unbroken} phase of the MSSM. We use improved propagators including resummation of hard thermal loops and the thermalization rate is computed at the one-loop level in the high temperature approximation. We find that the damping is typically dominated by scattering with gauge bosons, resulting in a damping rate of about $γ_{\Ht}\simeq 0.025T$, $γ_{\Wt}\simeq 0.065T$. The contribution from scattering with scalars is relatively small. Implications for bar…
Non-minimal supersymmetric models that predict a tree-level Higgs mass above the Minimal Supersymmetric Standard Model (MSSM) bound are well motivated by naturalness considerations. Indirect constraints on the stop sector parameters of such models are significantly relaxed compared to the MSSM; in particular, both stops can have weak-scale masses. We revisit the stop-catalyzed electroweak baryogenesis (EWB) scenario in this context. We find that the LHC measurements of the Higgs boson production and decay rates already rule out the possibility of stop-catalyzed EWB. We also introduce a gauge-i…
The phenomenology of supersymmetric models of inflation, where the inflationary vacuum energy is dominated by D-terms of a U(1), is investigated. Particular attention is paid to the questions of how to arrange for sufficient e-folds of inflation to occur, what kind of thermal history is expected after the end of inflation, and how to implement successful baryogenesis. Such models are argued to require a more restrictive symmetry structure than previously thought. In particular, it is non-trivial that the decays of the fields driving D-inflation can reheat the universe in such a way as to avoid…
Introducing heavy particles with strong couplings to the Higgs field can strengthen electroweak phase transition, through the entropy release mechanism from both bosons and fermions. We analyze the possibility of electroweak baryogenesis in the MSSM with new vector-like superfields. The new vector-like particles belong to the representation 5+5bar+10+10bar of SU(5). By analyzing in detail the effective potential at finite temperature, we show that a strongly first order electroweak phase transition in this model is ruled out by a combination of 125 GeV Higgs requirement, the bound for exotic q…
Electroweak baryogenesis (EWBG) in the MSSM can account for the cosmological baryon asymmetry, but only within a restricted region of the parameter space. In particular, MSSM EWBG requires a mostly right-handed stop that is lighter than the top quark and a standard model-like light Higgs boson. In the present work we investigate the effects of the light stop on Higgs boson production and decay. Relative to the standard model Higgs boson, we find a large enhancement of the Higgs production rate through gluon fusion and a suppression of the Higgs branching fraction into photon pairs. These modif…
A commonly accepted mechanism of generating baryon asymmetry in the minimal supersymmetric standard model (MSSM) depends on the CP violating relative phase between the gaugino mass and the Higgsino mu term. The direct constraint on this phase comes from the limit of electric dipole moments (EDM) of various light fermions. To avoid such a constraint, a scheme which assumes the first two generation sfermions are very heavy is usually evoked to suppress the one-loop EDM contributions. We point out that under such a scheme the most severe constraint may come from a new contribution to the electric…
Electroweak baryogenesis depends on the profile of the bubble wall created in the first-order phase transition. It is pointed out that CP violation in the Higgs sector of the MSSM could become large enough to explain the baryon asymmetry. We confirm this by solving the equations of motion for the Higgs fields with the effective potential at the transition temperature. That is, we present an example such that the transitional CP violation is realized and show the possibility that the baryon asymmetry of the universe may be produced, if marginally, by the $τ$ lepton interacting with the wall, wh…
The baryon asymmetry of the universe may originate in the phase transition at the end of hybrid inflation, provided that the reheat temperature is low enough. I show that if the field that triggers the end of inflation is the electroweak Higgs field and CP is violated, the transition leads to baryon asymmetry even if no preheating or non-thermal symmetry restoration takes place. I estimate the strength of this effect and the constraints it imposes on the inflationary model.
It is conventional wisdom that successful electroweak baryogenesis in the Minimal Supersymmetric extension of the Standard Model (MSSM) is in tension with the non-observation of electric dipole moments (EDMs), since the level of CP-violation responsible for electroweak baryogenesis is believed to generate unavoidably large EDMs. We show that CP-violation in the bino-Higgsino sector of the MSSM can account for successful electroweak baryogenesis without inducing large EDMs. This observation weakens the correlation between electroweak baryogenesis and EDMs, and makes the bino-driven electroweak …
In a supersymmetric left-right symmetric model, inflation, baryogenesis (via leptogenesis) and neutrino oscillations can become closely linked. A familiar ansatz for the neutrino Dirac masses and mixing of the two heaviest families, together with the MSW resolution of the solar neutrino puzzle, imply that 1 eV <_\sim m_{ν_{τ}<_\sim 9 eV. The predicted range for the mixing angle θ_μτwill be partially tested by the Chorus/Nomad experiment. The CP violating phase δ_{μτ} is also discussed.
Next-to-MSSM is a viable model which is equipped with two features suited for electroweak baryogensis (EWBG): first-order phase transition not restricted by the Higgs spectrum and tree-level CP violation in the Higgs sector free from the nEDM constraints. We study the model when the expectation value of the singlet scalar is of the weak scale. Then the vacuum stability condition puts a novel upper bound on the charged Higgs mass. We determined allowed parameter region by requiring that the each Higgs boson is heavier than 114GeV or its coupling to Z boson is smaller than 0.1.
In the minimal supersymmetric standard model (MSSM), a strongly first-order electroweak phase transition (EWPT) is only possible in a confined parameter region where one of the scalar top quarks is lighter than the top quark and the other one is as heavy as the SUSY breaking scale. If the MSSM is enlarged to accommodate vector-like quarks and their superpartners, we find that the strongly first-order EWPT is possible without requiring light scalar top quark at the one-loop level, in the limit where the lightest scalar Higgs boson of the MSSM behaves like the Higgs boson of the standard model a…
We propose a new scenario of Affleck-dine baryogenesis in the context of theories with large extra dimensions. In this paper we consider baryogenesis after thermal brane inflation and show how our mechanism works. We specifically consider models in which supersymmetry is broken at the distant brane.
We demonstrate that B-ball decay in the MSSM can naturally solve the puzzle of why the densities of baryons and dark matter in the Universe are similar. This requires that the B-balls survive thermalization and decay below the freeze-out temperature of the neutralino LSP, typically 1-10GeV. It is shown that this can happen if the baryon asymmetry originates from a squark condensate along the d=6 u^{c}d^{c}d^{c} D-flat direction of the MSSM scalar potential. For this to work the reheating temperature after inflation must be no greater than 10^3-10^5 GeV.
It is shown that, in the context of split supersymmetry, a simple model with a single complex scalar field can produce chaotic inflation and generate the observed amount of baryon asymmetry via the Affleck-Dine mechanism. While the inflaton quantum fluctuations give rise to curvature perturbation, we show that quantum fluctuations of the phase of the scalar field can produce baryonic isocurvature perturbation. Combining with constraints from WMAP data, all parameters in the model can be determined to within a narrow range.
We perform a comprehensive study of the dominant two- and higher-loop contributions to the $^{205}$Tl, neutron and muon electric dipole moments induced by Higgs bosons, third-generation quarks and squarks, charginos and gluinos in the Minimal Supersymmetric Standard Model (MSSM). We find that strong correlations exist among the contributing CP-violating operators, for large stop, gluino and chargino phases, and for a wide range of values of $\tanβ$ and charged Higgs-boson masses, giving rise to large suppressions of the $^{205}$Tl and neutron electric dipole moments below their present experim…
Thermal two-loop QCD corrections associated with light stops have a dramatic effect on the strength of the MSSM electroweak phase transition, making it more strongly first order as required for the viability of electroweak baryogenesis. We perform a perturbative analysis of the transition strength in this model, including these important contributions, extending previous work to arbitrary values of the pseudoscalar Higgs boson mass, m_A. We find a strong enough transition in a region with 2< tan beta < 4 and m_A > 120 GeV, a light Higgs boson with nearly standard couplings, and mass below 85 G…
We show that Q-balls naturally exist in the Minimal Supersymmetric Standard Model (MSSM) with soft SUSY breaking terms of the minimal N=1 SUGRA type. These are associated with the F- and D-flat directions of the scalar potential once radiative corrections are taken into account. We consider two distinct cases, corresponding to the "H_u L" (slepton) direction with L-balls and the "udd" and "uude" (squark) directions with B-balls. The L-ball always has a small charge, typically of the order of 1000, whilst the B-ball can have an arbitrarily large charge, which, when created cosmologically by the…
We construct an effective three dimensional theory for the MSSM at high temperatures in the limit of large-$m_{A}$. We analyse the two-loop effective potential of the 3D theory for the case of a light right handed stop to determine the precise region in the $m_{h}$-$m_{\tilde{t}_{R}}$ plane for which the sphaleron constraint for preservation of the baryon asymmetry is satisfied. We also compare with results previously obtained usind 3D and 4D calculations of the effective potential. A two-stage phase transition still persists for a small range of values of $m_{\tilde{t}_{R}}$. The allowed regi…
We explore a new possibility of electroweak baryogenesis in the next-to-minimal supersymmetric standard model. In this model, a strong first-order electroweak phase transition can be achieved due to the additional singlet Higgs field. The new impact of its superpartner (singlino) on the baryon asymmetry is investigated by employing the closed-time-path formalism. We find that the CP violating source term fueled by the singlino could be large enough to generate the observed baryon asymmetry of the Universe without any conflicts with the current constraints from the non-observation of the Thalli…
Recent lattice results have shown that there is no Standard Model (SM) electroweak phase transition (EWPT) for Higgs boson masses above \approx 72 GeV, which is below the present experimental limit. According to perturbation theory and 3-dimensional (3d) lattice simulations there could be an EWPT in the Minimal Supersymmetric Standard Model (MSSM) that is strong enough for baryogenesis up to m_h \approx 105 GeV. In this letter we present the results of our large scale 4-dimensional (4d) lattice simulations for the MSSM EWPT. We carried out infinite volume and continuum limits and found a trans…
We make use of the formalism developed in Ref. [1], and calculate the chargino mediated baryogenesis in the Minimal Supersymmetric Standard Model. The formalism makes use of a gradient expansion of the Kadanoff-Baym equations for mixing fermions. For illustrative purposes, we first discuss the semiclassical transport equations for mixing bosons in a space-time dependent Higgs background. To calculate the baryon asymmetry, we solve a standard set of diffusion equations, according to which the chargino asymmetry is transported to the top sector, where it biases sphaleron transitions. At the end …
The MSSM has flat directions in its scalar potential, along which it is natural for Bose condensates of squarks to form in the early Universe. A baryon asymmetry can be induced in these condensates via Affleck-Dine baryogenesis. The condensates are unstable with respect to fragmentation to "B-balls", solitons made of squarks and carrying baryon number, which, if they survive thermalization, fill the Universe down to low temperatures, much lower than that of the electroweak phase transition, with interesting cosmological consequences. In particular, their decay implies a similar number density …
We consider the B-ball cosmology of the MSSM in the context of D-term inflation models where the reheating temperature is determined by the Affleck-Dine mechanism to be of the order of 1 GeV. We show that such a low reheating temperature can arise quite naturally as the result of a symmetry which is required to maintain the flatness of the inflaton potential. In this case the B-balls will decay well after the freeze-out temperature of the LSP, allowing baryons and cold dark matter to originate primarily from B-ball decays.
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, $H_1-H_2$, as the source of biasing sphalerons to create the baryon asymmetry. We point out that the current for the orthogonal linear combination, $H_1+H_2$, is larger by several orders of magnitude. Although this increases the efficiency of electroweak baryogenesis, we nevertheless find …
We discuss the generation of the baryon asymmetry by a strong first order electroweak phase transition in the early universe, particularly in the context of the MSSM. This requires a thorough numerical treatment of the bubble wall profile in the case of two Higgs fields. CP violating complex particle masses varying with the Higgs field in the wall are essential. Since in the MSSM there is no indication of spontaneous CP violation around the critical temperature (contrary to the NMSSM) we have to rely on standard explicit CP violation. Using the WKB approximation for particles in the plasma we …
We investigate the implications of the Higgs rate measurements from Run 1 of the LHC for the mass of the light scalar top partner (stop) in the Minimal Supersymmetric Standard Model (MSSM). We focus on light stop masses, and we decouple the second, heavy stop and the gluino to the multi-TeV range in order to obtain a Higgs mass of around 125 GeV. We derive lower mass limits for the light stop within various scenarios, taking into account the effects of a possibly light scalar tau partner (stau) or chargino on the Higgs rates, of additional Higgs decays to undetectable new physics, as well as o…
Electroweak baryogenesis provides an attractive explanation of the origin of the matter-antimatter asymmetry that relies on physics at the weak scale and thus it is testable at present and near future high-energy physics experiments. Although this scenario may not be realized within the Standard Model, it can be accommodated within the MSSM provided there are new CP-violating phases and the lightest stop mass is smaller than the top-quark mass. In this work we provide an evaluation of the values of the stop (m_{\tilde t}) and Higgs (m_H) masses consistent with the requirements of electroweak b…
In the context of the MSSM the Light Stop Scenario (LSS) is the only region of parameter space that allows for successful Electroweak Baryogenesis (EWBG). This possibility is very phenomenologically attractive, since it allows for the direct production of light stops and could be tested at the LHC. The ATLAS and CMS experiments have recently supplied tantalizing hints for a Higgs boson with a mass of ~ 125 GeV. This Higgs mass severely restricts the parameter space of the LSS, and we discuss the specific predictions made for EWBG in the MSSM. Combining data from all the available ATLAS and CMS…
We discuss the constraints on the inhomogeneous reheating scenario. In particular, we discuss the prospects for low scale inflation with a Hubble constant of the order of the gravitino mass, and the possibility that an MSSM flat direction is responsible for the density fluctuations. Thermal effects are generically fatal for the scenario, and can only be avoided for small enough mass and couplings of the flat direction field, excluding MSSM flat directions. Prompt decay at the end of inflation bypasses thermal constraints, and is compatible with both low scale inflation and MSSM flat directions…
Non-perturbative preheating decay of post-inflationary condensates often results in a high density, low momenta, non-thermal gas. In the case where the non-perturbative classical evolution also leads to Q-balls, this effect shields them from instant dissociation, and may radically change the thermal history of the universe. For example, in a large class of inflationary scenarios, motivated by the MSSM and its embedding in string theory, the reheat temperature changes by a multiplicative factor of $10^{12}$.
We perform a study on the predictions of electric-dipole moments (EDMs) of neutron, Mercury (Hg), Thallium (Tl), deuteron, and Radium (Ra) in the framework of next-to-minimal supersymmetric standard model (NMSSM) with CP-violating parameters in the superpotential and soft-supersymmetry-breaking sector. We confine to the case in which only the physical tree-level CP phase $(ϕ'_λ- ϕ'_κ)$, associated with the couplings of the singlet terms in the superpotential and with the vacuum-expectation-values (VEVs), takes on a nonzero value. We found that the one-loop contributions from neutralinos are mo…
The basic idea of baryogenesis is lectured to introduce non-experts to this subject. Some recent topics, necessarily subjective in view of short time limitation, are also presented to show how the initial condition for baryogenesis is realized in the new framework of inflation.
Electroweak baryogenesis could be very efficient at the end of an electroweak-scale inflation. Reheating that followed inflation could create a highly non-equilibrium plasma, in which the baryon number violating transitions were rapid. In addition, the time-dependent motions of the scalar degrees of freedom could provide the requisite CP violation. If the final reheat temperature was below 100 GeV, there was no wash-out of the baryon asymmetry after thermalization. The observed value of the baryon asymmetry can be attained in a number of models, some of which do not require a significant depar…
Electroweak baryogenesis is an attractive scenario for the generation of the baryon asymmetry of the universe as its realization depends on the presence at the weak scale of new particles which may be searched for at high energy colliders. In the MSSM it may only be realized in the presence of light stops, and with moderate or small mixing between the left- and right-handed components. Consistency with the observed Higgs mass around 125 GeV demands the heavier stop mass to be much larger than the weak scale. Moreover the lighter stop leads to an increase of the gluon-gluon fusion Higgs product…
Modular cosmology is plagued by overproduction of unwanted relics, gravitinos and especially moduli, at relatively low energy scales. Thermal inflation provides a compelling solution to this moduli problem, but invalidates most baryogenesis scenarios. We propose a simple model in which the MSSM plus neutrino mass term $(LH_u)^2$ is supplemented by a minimal flaton sector to drive the thermal inflation, and make two crucial assumptions: the flaton vacuum expectation value generates the $μ$-term of the MSSM and $m_L^2 + m_{H_u}^2 < 0$. The second assumption is particularly interesting in that it…
There can exist a parallel `mirror' world which has the same particle physics as the observable world and couples the latter only gravitationally. The nucleosynthesis bounds demand that the mirror sector should have a smaller temperature than the ordinary one. By this reason its evolution should be substantially deviated from the standard cosmology as far as the crucial epochs like baryogenesis, nucleosynthesis etc. are concerned. Starting from an inflationary scenario which could explain the different initial temperatures of the two sectors, we study the time history of the early mirror unive…
We present a novel scenario for baryogenesis in a hybrid inflation model at the electroweak scale, in which the Standard Model Higgs field triggers the end of inflation. One of the conditions for successful baryogenesis, the departure from thermal equilibrium, is naturally achieved at the stage of preheating after inflation. The inflaton oscillations induce large occupation numbers for long-wavelength configurations of Higgs and gauge fields, which leads to a large rate of sphaleron transitions. We estimate this rate during the first stages of reheating and evaluate the amount of baryons produ…
We study a baryogenesis mechanism operating in the context of hyperextended inflation and making use of a coupling between the scalar field and a standard model global current, such as B or B-L. The method is efficient at temperatures at which these currents are not conserved due to some higher dimensional operator. The particle physics and cosmological phenomenology are discussed. We consider constraints stemming from nucleosynthesis and solar system experiments.
We evaluate the constraints that the COBE observations put on baryogenesis in inflationary cosmologies.We consider the supersymmetric version of the proposal of Fukugita and Yanagida, that the baryon asymmetry of the universe is created by nonperturbative electroweak reprocessing of a lepton asymmetry generated in the decay of heavy right-handed see-saw (s)neutrinos. We review our recent proposal of a mechanism for baryogenesis via sphaleron reprocessing of a lepton asymmetry generated by (s)neutrino mass effects on flat direction scalar condensate oscillations. Finally we analyze in detail th…
Affleck-Dine (AD) baryogenesis along a d=6 flat direction in gauge-mediated supersymmetry-breaking (GMSB) models can produce unstable Q-balls which naturally have field strength similar to the messenger scale. In this case a new kind of Q-ball is formed, intermediate between gravity-mediated and gauge-mediated type. We study in detail these new Q-ball solutions, showing how their properties interpolate between standard gravity-mediated and gauge-mediated Q-balls as the AD field becomes larger than the messenger scale. It is shown that E/Q for the Q-balls can be greater than the nucleon mass bu…
We propose a new scenario of Affleck-Dine baryogenesis where a flat direction in the MSSM generates B-L asymmetry just after the end of inflation. The resulting amount of baryon asymmetry is independent of low-energy supersymmetric models but is dependent on inflation models. We consider the hybrid and chaotic inflation models and find that reheating temperature is required to be higher than that in the conventional scenario of Affleck-Dine baryogenesis. In particular, non-thermal gravitino-overproduction problem is naturally avoided in the hybrid inflation model. Our results imply that Afflec…
We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations.
I describe work done in collaboration with M. Joyce and K. Kainulainen on (1) the strength of the electroweak phase transition in the MSSM and (2) the mechanism for producing the baryon asymmetry during the phase transition. In the former we compare the effective potential and dimensional reduction methods for describing the phase transition and search the parameter space of the MSSM for those values where it is strong enough. In the latter we give a systematic computation of the baryon asymmetry due the CP-violating force acting on charginos in the vicinity of the bubble wall. We find that a …
We consider the construction of inverted hybrid inflation models in which the vacuum energy during inflation is at the TeV scale, and the inflaton couples to the Higgs field. Such models are of interest in the context of some recently proposed models of electroweak baryogenesis. We demonstrate how constraints on these models arise from quantum corrections, and how self-consistent examples may be constructed, albeit at the expense of fine-tuning. We discuss two possible ways in which the baryon asymmetry of the universe may be produced in these models. One of them is based on preheating and a c…
Thermal inflation can solve serious cosmological problems such as overproduction of gravitinos and moduli. However, it also dilutes the preexisting baryon asymmetry. We investigate a possibility that Affleck-Dine mechanism works after thermal inflation and generate the baryon number at an acceptable level using lattice calculation. We find that a proper amount of baryon number can be generated for appropriate model parameters.
