# Low reheating temperatures in monomial and binomial inflationary models

## Abstract

We investigate the allowed range of reheating temperature values in light of the Planck 2015 results and the recent joint analysis of Cosmic Microwave Background (CMB) data from the BICEP2/Keck Array and Planck experiments, using monomial and binomial inflationary potentials. While the well studied ϕ{sup 2} inflationary potential is no longer favored by current CMB data, as well as ϕ{sup p} with p>2, a ϕ{sup 1} potential and canonical reheating (w{sub re}=0) provide a good fit to the CMB measurements. In this last case, we find that the Planck 2015 68% confidence limit upper bound on the spectral index, n{sub s}, implies an upper bound on the reheating temperature of T{sub re}≲6×10{sup 10} GeV, and excludes instantaneous reheating. The low reheating temperatures allowed by this model open the possibility that dark matter could be produced during the reheating period instead of when the Universe is radiation dominated, which could lead to very different predictions for the relic density and momentum distribution of WIMPs, sterile neutrinos, and axions. We also study binomial inflationary potentials and show the effects of a small departure from a ϕ{sup 1} potential. We find that as a subdominant ϕ{sup 2} term in the potential increases, firstmore »

- Authors:

- Department of Physics and Astronomy, UCLA,475 Portola Plaza, Los Angeles, CA 90095 (United States)

- Publication Date:

- Sponsoring Org.:
- SCOAP3, CERN, Geneva (Switzerland)

- OSTI Identifier:
- 22454562

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 06; Other Information: PUBLISHER-ID: JCAP06(2015)039; OAI: oai:repo.scoap3.org:10793; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AXIONS; COSMOLOGICAL INFLATION; GEV RANGE; MEV RANGE; NEUTRINOS; NONLUMINOUS MATTER; RELICT RADIATION; UNIVERSE; WIMPS

### Citation Formats

```
Rehagen, Thomas, and Gelmini, Graciela B.
```*Low reheating temperatures in monomial and binomial inflationary models*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/06/039.

```
Rehagen, Thomas, & Gelmini, Graciela B.
```*Low reheating temperatures in monomial and binomial inflationary models*. United States. doi:10.1088/1475-7516/2015/06/039.

```
Rehagen, Thomas, and Gelmini, Graciela B. Tue .
"Low reheating temperatures in monomial and binomial inflationary models". United States.
doi:10.1088/1475-7516/2015/06/039.
```

```
@article{osti_22454562,
```

title = {Low reheating temperatures in monomial and binomial inflationary models},

author = {Rehagen, Thomas and Gelmini, Graciela B.},

abstractNote = {We investigate the allowed range of reheating temperature values in light of the Planck 2015 results and the recent joint analysis of Cosmic Microwave Background (CMB) data from the BICEP2/Keck Array and Planck experiments, using monomial and binomial inflationary potentials. While the well studied ϕ{sup 2} inflationary potential is no longer favored by current CMB data, as well as ϕ{sup p} with p>2, a ϕ{sup 1} potential and canonical reheating (w{sub re}=0) provide a good fit to the CMB measurements. In this last case, we find that the Planck 2015 68% confidence limit upper bound on the spectral index, n{sub s}, implies an upper bound on the reheating temperature of T{sub re}≲6×10{sup 10} GeV, and excludes instantaneous reheating. The low reheating temperatures allowed by this model open the possibility that dark matter could be produced during the reheating period instead of when the Universe is radiation dominated, which could lead to very different predictions for the relic density and momentum distribution of WIMPs, sterile neutrinos, and axions. We also study binomial inflationary potentials and show the effects of a small departure from a ϕ{sup 1} potential. We find that as a subdominant ϕ{sup 2} term in the potential increases, first instantaneous reheating becomes allowed, and then the lowest possible reheating temperature of T{sub re}=4 MeV is excluded by the Planck 2015 68% confidence limit.},

doi = {10.1088/1475-7516/2015/06/039},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 06,

volume = 2015,

place = {United States},

year = {Tue Jun 23 00:00:00 EDT 2015},

month = {Tue Jun 23 00:00:00 EDT 2015}

}