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Late-decaying particles naturally arise in many extensions of the Standard Model, directly impacting key cosmological processes in the early universe, such as Big Bang Nucleosynthesis (BBN). BBN studies often consider electromagnetic energy…
We study soft leptogenesis in gauge mediated supersymmetry breaking models with an enhanced A-term for the right-handed neutrino. We find that this scenario can explain the baryon asymmetry of the present universe, consistently with the…
Gravitino production and decay in the inflationary universe are reexamined. Assuming that the gravitino mainly decays into a photon and a photino, we calculate the upperbound on the reheating temperature. Compared to previous works, we have…
Interactions of heavy Majorana neutrinos in the thermal phase of the early universe may be the origin of the cosmological matter-antimatter asymmetry. This mechanism of baryogenesis implies stringent constraints on light and heavy Majorana…
We explore here a new mechanism by which the out of equilibrium decay of heavy gravitinos, followed by possible R-parity violating decays in the Minimal Supersymmetric Standard Model (MSSM) can generate the baryon asymmetry of the universe.…
At high temperatures, gravitinos are generated in inelastic scattering processes with particles that are in thermal equilibrium with the hot primordial plasma. We consider the regeneration of gravitinos that starts with completion of…
The low reheat temperature at the end of inflation from the gravitino bound constrains the creation of heavy Majorana neutrinos associated with models of leptogenesis. However, a detailed view of the reheating of the Universe at the end of…
Stable particle dark matter may well originate during the decay of long-lived relic particles, as recently extensively examined in the cases of the axino, gravitino, and higher-dimensional Kaluza-Klein (KK) graviton. It is shown that in…
In recent work, it has been argued that multi-TeV masses for scalar superpartners are not unnatural. Indeed, they appear to have significant phenomenological virtues. Here we explore the implications of such `focus point' supersymmetry for…
We examine a scenario in which the reheating temperature $T_R$ after inflation is so low that it is comparable to, or lower than, the freeze out temperature of ordinary WIMPs. In this case the dark matter relic abundance is reduced, thus…
We consider the dynamics of the supersymmetry-breaking scalar field and the production of dark matter gravitinos via its decay in a gauge-mediated supersymmetry breaking model with metastable vacuum. We find that the scalar field amplitude…
Popular extensions of the standard model of particle physics feature new fields and symmetries which could, for example, dynamically generate neutrino masses from $B-L$ spontaneous symmetry breaking. If a new light scalar that decays into…
In all supersymmetric theories, gravitinos, with mass suppressed by the Planck scale, are an obvious candidate for dark matter; but if gravitinos ever reached thermal equilibrium, such dark matter is apparently either too abundant or too…
We examine various predictions of the minimal supersymmetric standard model coupled to minimal supergravity. The model is characterised by a small set of parameters at the unification scale. The supersymmetric particle spectrum at low…
We revisit astrophysical constraints on models with an ultra-light gravitino, in particular extending the analysis to more general models and the case of R-parity breaking. These constraints allow to restrict the value of the gravitino mass…
Gravitino production and decay in the inflationary universe are reexanimed. Assuming that gravitino mainly decays into photon and photino, we have calculated the upperbound of the reheating temperature. Compared to previous works, we have…
We consider heavy stable neutral particles in the context of supergravity and show that a gravitationally suppressed inflaton decay can produce such particles in cosmologically interesting abundances within a wide mass range $10^3 {\rm GeV}…
Affleck-Dine baryogenesis, accompanied by the formation and subsequent decay of Q-balls, can generate both the baryon asymmetry of the universe and dark matter in the form of gravitinos. The gravitinos from Q-ball decay dominate over the…
In the supersymmetric standard model there exist pure gravity contributions to the soft mass parameters which arise via the superconformal anomaly. We consider the low-energy phenomenology with a mass spectrum dominated by the…
SuperWeakly-Interacting Massive Particles (superWIMPs) produced in the late decays of other particles are well-motivated dark matter candidates and may be favored over standard Weakly-Interacting Massive Particles (WIMPs) by small scale…