Cosmological gravitino production in gauge mediated supersymmetry breaking models

Abstract

We study the cosmological gravitino production in gauge mediated supersymmetry breaking models, while properly taking into account the existence of the messenger mass scale. It is found that for sizable parameter range of the model the messenger sector contribution leads to more stringent upper bound on the reheat temperature obtained from the condition that the universe should not be overclosed by relic gravitinos. However it turns out that in the limit of relatively low messenger scale and large gravitino mass, the relic gravitino mass density can be smaller than the critical density independently of the reheat temperature, suggesting the possibility in this limit to have a high reheat temperature without the dilution of gravitinos at late time.

Axino cold dark matter revisited

“…[59]. The relevant 2-body scattering cross sections are summarized in table 2, keeping in mind that the physical cross-sections are eq.…”

Gravitino thermal production revisited and a new cosmological scenario of gauge mediation

“…An explicit calculation of the goldstino production shows that the goldstino relic abundance is not necessarily proportional to T R [28], which contradicts with the estimation in supergravity. We examine this apparent contradiction by calculating the scattering amplitudes of goldstino/gravitino production process both with a global SUSY Lagrangian and a supergravity Lagrangian.…”

“…However, it has been argued in ref. [28], those estimates should be modified in GMSB models for a temperature higher than the messenger scale M mess . The authors of ref.…”

“…[28] is clear in terms of global SUSY, it seems somewhat obscure in the supergravity description. In the global SUSY case, the MSSM fields couple to the goldstino (the longitudinal component of the gravitino) only though the loops of the messenger fields.…”

Light gravitinos at colliders and implications for cosmology

“…For example, in our discussion we have neglected the nonthermal contribution to the gravitino abundance from out-of-equilibrium decays of other supersymmetric particles. There may also be other significant modes of gravitino production or dilution, including processes involving the messenger particles responsible for GMSB [39][40][41][42][43][44], nonthermal production via oscillations of the inflaton field [45], Q-ball decays [46], and various other mechanisms [47]. There may thus be other reasons why the gravitino abundance or temperature differs from those in the canonical thermal-production scenario; this may be true even if mG & 30 eV.…”