Seed perturbations for primordial magnetic fields from MSSM flat directions

We demonstrate that the MSSM flat directions can naturally account for the seed magnetic fields in the early Universe. The non-zero vacuum expectation value of an MSSM flat direction condensate provides masses to the gauge fields and thereby breaks conformal invariance. During inflation the condensate receives spatial perturbations and $SU(2) x U(1)_Y$ gauge currents are generated together with (hyper)magnetic fields. When these long wavelength vector perturbations reenter our horizon they give rise to $U(1)_{em}$ magnetic fields with an amplitude of $10^{-30}$ Gauss, as required by the dynamo mechanism.Comment: 4 pages, RevTeX

Q-ball formation in the wake of Hubble-induced radiative corrections

We discuss some interesting aspects of the $\rm Q$-ball formation during the early oscillations of the flat directions. These oscillations are triggered by the running of soft $({\rm mass})^2$ stemming from the nonzero energy density of the Universe. However, this is quite different from the standard $\rm Q$-ball formation. The running in presence of gauge and Yukawa couplings becomes strong if $m_{1/2}/m_0$ is sufficiently large. Moreover, the $\rm Q$-balls which are formed during the early oscillations constantly evolve, due to the redshift of the Hubble-induced soft mass, until the low-energy supersymmtery breaking becomes dominant. For smaller $m_{1/2}/m_0$, $\rm Q$-balls are not formed during early oscillations because of the shrinking of the instability band due to the Hubble expansion. In this case the $\rm Q$-balls are formed only at the weak scale, but typically carry smaller charges, as a result of their amplitude redshift. Therefore, the Hubble-induced corrections to the flat directions give rise to a successful $\rm Q$-ball cosmology.Comment: 7 revtex pages, few references corrected and added, final version to appear in Phys. Rev.

Reheating as a surface effect

We describe a new mechanism for reheating the Universe through evaporation of a surface charge of a fragmented inflaton condensate. We show that for a range of Yukawa coupling of the inflaton to the matter sector evaporation gives rise to a much smaller reheat temperature compared to the standard perturbative decay. As a consequence, reheating through a surface effect could solve the gravitino and moduli over production problem in inflationary models without fine tuning the Yukawa sector.Comment: 4 page

MSSM Higgses as the source of reheating and all matter

We consider the possibility that the dark energy responsible for inflation is deposited into extra dimensions outside of our observable universe. Reheating and all matter can then be obtained from the MSSM flat direction condensate involving the Higgses $H_u$ and $H_d$, which acquires large amplitude by virtue of quantum fluctuations during inflation. The reheat temperature is $T_{RH} \lesssim 10^9$ GeV so that there is no gravitino problem. We find a spectral index $n_s\approx 1$ with a very weak dependence on the Higgs potential.Comment: 4 page

Curvatons in Supersymmetric Models

We study the curvaton scenario in supersymmetric framework paying particular attention to the fact that scalar fields are inevitably complex in supersymmetric theories. If there are more than one scalar fields associated with the curvaton mechanism, isocurvature (entropy) fluctuations between those fields in general arise, which may significantly affect the properties of the cosmic density fluctuations. We examine several candidates for the curvaton in the supersymmetric framework, such as moduli fields, Affleck-Dine field, $F$- and $D$-flat directions, and right-handed sneutrino. We estimate how the isocurvature fluctuations generated in each case affect the cosmic microwave background angular power spectrum. With the use of the recent observational result of the WMAP, stringent constraints on the models are derived and, in particular, it is seen that large fraction of the parameter space is excluded if the Affleck-Dine field plays the role of the curvaton field. Natural and well-motivated candidates of the curvaton are also listed.Comment: 34 pages, 5 figure

Hybridized Affleck-Dine baryogenesis

We propose a novel scenario for Affleck-Dine baryogenesis in the braneworld, considering the hybrid potential for the Affleck-Dine field. Destabilization of the flat direction is not due to the Hubble parameter, but is induced by a trigger field. The moduli for the brane distance plays the role of the trigger field. Q-balls are unstable in models with large extra dimensions.Comment: 10pages, plain latex2e, references added, to appear in PR

Resonant decay of flat directions

We study preheating, i.e., non-perturbative resonant decay, of flat direction fields, concentrating on MSSM flat directions and the right handed sneutrino. The difference between inflaton preheating and flaton preheating, is that the potential is more constraint in the latter case. The effects of a complex driving field, quartic couplings in the potential, and the presence of a thermal bath are important and cannot be neglected. Preheating of MSSM flat directions is typically delayed due to out-of-phase oscillations of the real and imaginary components and may be preceded by perturbative decay or $Q$-ball formation. Particle production due to the violation of adiabaticity is expected to be inefficient due to back reaction effects. For a small initial sneutrino VEV, $\lesssim m_N/h$ with $m_N$ the mass of the right handed sneutrino and $h$ a yakawa coupling, there are tachyonic instabilities. The $D$-term quartic couplings do not generate an effective mass for the tachyonic modes, making it an efficient decay channel. It is unclear how thermal scattering affects the resonance.Comment: 20 pages, 4 figure

Q ball inflation

We show that inflation can occur in the core of a Q-ball.Comment: 11 pages, latex2e, no figure, references added, final version to appear in PR

Affleck-Dine dynamics and the dark sector of pangenesis

Pangenesis is the mechanism for jointly producing the visible and dark matter asymmetries via Affleck-Dine dynamics in a baryon-symmetric universe. The baryon-symmetric feature means that the dark asymmetry cancels the visible baryon asymmetry and thus enforces a tight relationship between the visible and dark matter number densities. The purpose of this paper is to analyse the general dynamics of this scenario in more detail and to construct specific models. After reviewing the simple symmetry structure that underpins all baryon-symmetric models, we turn to a detailed analysis of the required Affleck-Dine dynamics. Both gravity-mediated and gauge-mediated supersymmetry breaking are considered, with the messenger scale left arbitrary in the latter, and the viable regions of parameter space are determined. In the gauge-mediated case where gravitinos are light and stable, the regime where they constitute a small fraction of the dark matter density is identified. We discuss the formation of Q-balls, and delineate various regimes in the parameter space of the Affleck-Dine potential with respect to their stability or lifetime and their decay modes. We outline the regions in which Q-ball formation and decay is consistent with successful pangenesis. Examples of viable dark sectors are presented, and constraints are derived from big bang nucleosynthesis, large scale structure formation and the Bullet cluster. Collider signatures and implications for direct dark matter detection experiments are briefly discussed. The following would constitute evidence for pangenesis: supersymmetry, GeV-scale dark matter mass(es) and a Z' boson with a significant invisible width into the dark sector.Comment: 51 pages, 7 figures; v2: minor modifications, comments and references added; v3: minor changes, matches published versio

Minimal supersymmetric standard model flat direction as a curvaton

We study in detail the possibility that the flat directions of the Minimal Supersymmetric Standard Model (MSSM) could act as a curvaton and generate the observed adiabatic density perturbations. For that the flat direction energy density has to dominate the Universe at the time when it decays. We point out that this is not possible if the inflaton decays into MSSM degrees of freedom. If the inflaton is completely in the hidden sector, its decay products do not couple to the flat direction, and the flat direction curvaton can dominate the energy density. This requires the absence of a Hubble-induced mass for the curvaton, e.g. by virtue of the Heisenberg symmetry. In the case of hidden radiation, $n=9$ is the only admissible direction; for other hidden equations of state, directions with lower $n$ may also dominate. We show that the MSSM curvaton is further constrained severely by the damping of the fluctuations, and as an example, demonstrate that in no-scale supergravity it would fragment into $Q$ balls rather than decay. Damping of fluctuations can be avoided by an initial condition, which for the $n=9$ direction would require an initial curvaton amplitude of $\sim 10^{-2}M_p$, thereby providing a working example of the MSSM flat direction curvaton