Supersymmetric D-term Inflation and B-ball Baryogenesis

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. [email protected]; [email protected] The MSSM [1] is known to admit non-topological solitons in its spectrum [2]; in particular, B-balls (Q-balls [3, 4] with baryonic charge) can exist. In a cosmological scenario which includes inflation these can be copiously produced by the breakdown of scalar condensates along flat directions of the MSSM. In the case of gauge-mediated SUSY breaking, extensively discussed in references [5-10], the B-balls are stable and could account for cold dark matter [6]. In the case of gravity-mediated breaking, studied in [11, 12], the B-balls are unstable but nevertheless, if they can survive thermalization, they are typically long-lived enough to decay much after the electroweak phase transition, leading to a variant of the Affleck-Dine mechanism [14] which we call B-ball Baryogenesis (BBB) [11, 12]. The requirement that they can survive thermalization implies that the B-balls in R-parity conserving models originate from a d=6 AD condensate and imposes an upper bound on the reheating temperature of 10 GeV [11, 12]. Such B-balls can protect a B asymmetry originating in the AD condensate from the effects of additional B-L violating interactions, which would otherwise wash out the B asymmetry when combined with anomalous B+L violation [11]. In addition, if the reheating temperature is sufficiently low that the B-balls decay below the freeze-out temperature of the lightest SUSY particle (LSP), then cold dark matter can mostly come from B-ball decays rather than from thermal relics. This opens up the possibility of relating the number density of dark matter particles to that of the baryons, allowing for an explaination of their observed similarity for the case of dark matter particles with weak scale masses [12]. Since BBB requires low reheating temperatures, it is important to consider whether low reheating temperatures are a natural feature of realistic SUSY inflation models. We will show that in D-term inflation models [15, 16] very low reheating temperatures are indeed a natural feature. In general, SUSY inflation models can be classified as either For D-term inflation models, depending on whether the energy density during inflation comes from the FDepending on the details of the hidden sector and its interaction with the observable sector, it is conceivable that SUSY breaking could be suppressed for large values of the condensate field, leading to stable B-balls in the case of gravity-mediated SUSY breaking [13].