About
The early Universe is an efficient source of particle production, particularly for light scalar fields. We study the generation of stable scalars that interact only through gravity, focusing on their production during inflation and throughout single- and multi-stage reheating. Gravitational particle production mechanisms are known to be highly efficient and can easily lead to an overabundant relic density, threatening the viability of non-thermal dark-matter scenarios such as freeze-in. We extend previous studies by deriving the scalar abundance for general reheating histories and demonstrate how additional reheating stages can significantly modify the final relic density. Our results show that avoiding overproduction without fine-tuning the gravitational Wilson coefficients typically requires low reheating temperatures.
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The talk
Credits and licence
- Institution
- CERN
- Speaker
- Francesco Costa
- Year
- 2026
- Language
- English
- Subjects
- Physics
- Source
- CERN
- Licence
- CERN, as CERN states it. CERN's terms
- Attribution
- © CERN. CERN provides its audiovisual media free of charge for educational and informational use, credited to CERN; this lecture is shown in CERN's own player.
- Who can watch
- CERN gives no rating. Invisible Network shows it to Tweens profiles and older, judged from what the source says about it. How courses are placed