Gravitino problem in minimal supergravity inflation

Abstract

We study non-thermal gravitino production in the minimal supergravity inflation. In this minimal model utilizing orthogonal nilpotent superfields, the particle spectrum includes only graviton, gravitino, inflaton, and goldstino. We find that a substantial fraction of the cosmic energy density can be transferred to the longitudinal gravitino due to non-trivial change of its sound speed. This implies either a breakdown of the effective theory after inflation or a serious gravitino problem.

Constrained superfields and applications

“…Constrained superfields and non-linear realizations have various applications: For example the Supersymmetric Standard Model [14][15][16], the current de Sitter phase of our universe [17][18][19][20][21][22][23][24][25][26][27], or the inflationary phase [28][29][30][31][32][33][34][35][36][37][38][39]. The String/Brane origin of constrained superfields is also under study [40][41][42][43][44][45][46][47][48][49][50][51].…”

“…Finally we stress that this description is only valid when Let us close this part by reporting a very recent development in the field. It has been shown in [39] that, unless the function g entering the superpotential is very tuned, the models (3.41) might suffer from an explosive gravitino production after inflation.…”

Probing the BSM physics with CMB precision cosmology: an application to supersymmetry

“…Also gravitinos are produced during the preheating stage via its non-perturbative decay of the inflaton [59,60,61,62,63,64,65], from the decay of the supersymmetry breaking field, see e.g. [66,67,68], or other moduli [69,70,71].…”

“…The gravitinos, that are unstable, are produced via thermal scatterings, non-thermal decays of sfermions and possible decays of scalars beyond MSSM such as the inflaton [57,58,59,60,61,62,63,64,65] and the supersymmetry breaking field or other moduli [69,70,71]. Focusing on the MSSM sector the gravitinos dominate the universe either for large enough reheating temperature, T rh 5 × 10 14 (m 3/2 /10 5 GeV) 1/2 GeV, or large enough sfermion masses, mf 2 × 10 8 (m 3/2 /10 5 GeV) 5/6 [42].…”

From linear to non-linear SUSY and back again

“…In this spirit, constrained superfields have been used for the effective description of inflationary models that are embedded in supergravity [15][16][17][18][19][20][21][22][23][24][25][26], but also to study more general brane supersymmetry breaking scenarios in string theory reductions to four dimensions. While explicit string constructions based on tachyon-free non-BPS systems are known since some time [27][28][29] and their non-linear supersymmetry has been studied in detail [30,31], their connection with the constrained superfields are still not fully understood [32][33][34][35][36][37][38].…”