Gravitino overproduction in inflaton decay

Masahiro Kawasaki, Fuminobu Takahashi, T. T. Yanagida

Research output: Contribution to journalArticlepeer-review

147 Citations (Scopus)


Most of the inflation models end up with non-vanishing vacuum expectation values of the inflaton fields φ{symbol} in the true vacuum, which induce, in general, non-vanishing auxiliary field Gφ{symbol} for the inflaton potential in supergravity. We show that the presence of nonzero Gφ{symbol} gives rise to inflaton decay into a pair of the gravitinos and are thereby severely constrained by cosmology especially if the gravitino is unstable and its mass is in a range of O (100)   GeV - O (10)   TeV. For several inflation models, we explicitly calculate the values of Gφ{symbol} and find that most of them are excluded or on the verge of being excluded for the gravitino mass in that range. We conclude that an inflation model with vanishing Gφ{symbol}, typically realized in a chaotic inflation, is favored in a sense that it naturally avoids the potential gravitino overproduction problem.

Original languageEnglish
Pages (from-to)8-12
Number of pages5
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number1
Publication statusPublished - 2006 Jun 29


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