# Symmetry breaking indication for supergravity inflation in light of the Planck 2015

## Abstract

Supergravity (SUGRA) theories with exact global U(1) symmetry or shift symmetry in Kähler potential provide natural frameworks for inflation. However, quadratic inflation is disfavoured by the new results on primordial tensor fluctuations from the Planck Collaboration. To be consistent with the new Planck data, we point out that the explicit symmetry breaking is needed, and study these two SUGRA inflation in detail. For SUGRA inflation with global U(1) symmetry, the symmetry breaking term leads to a trigonometric modulation on inflaton potential. Coefficient of the U(1) symmetry breaking term is of order 10{sup −2}, which is sufficient large to improve the inflationary predictions while its higher order corrections are negligible. Such models predict sizeable tensor fluctuations and highly agree with the Planck results. In particular, the model with a linear U(1) symmetry breaking term predicts the tensor-to-scalar ratio around r∼0.01 and running spectral index α{sub s}∼−0.004, which comfortably fit with the Planck observations. For SUGRA inflation with breaking shift symmetry, the inflaton potential is modulated by an exponential factor. The modulated linear and quadratic models are consistent with the Planck observations. In both types of models the tensor-to-scalar ratio can be of order 10{sup −2}, which will be tested by themore »

- Authors:

- State Key Laboratory of Theoretical Physics, and Kavli Institute for Theoretical Physics China (KITPC), Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China)
- (China)
- George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX 77843 (United States)
- (HARC), Mitchell Campus, Woodlands, TX 77381 (United States)
- (Greece)

- Publication Date:

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

- OSTI Identifier:
- 22458369

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 09; Other Information: PUBLISHER-ID: JCAP09(2015)006; OAI: oai:repo.scoap3.org:11629; 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; COSMOLOGICAL INFLATION; SCALAR FIELDS; SUPERGRAVITY; SUPERSYMMETRY; SYMMETRY BREAKING; TENSOR FIELDS; U-1 GROUPS

### Citation Formats

```
Li, Tianjun, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, Li, Zhijin, Nanopoulos, Dimitri V., Astroparticle Physics Group, Houston Advanced Research Center, and Academy of Athens, Division of Natural Sciences, 28 Panepistimiou Avenue, Athens 10679.
```*Symmetry breaking indication for supergravity inflation in light of the Planck 2015*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/09/006.

```
Li, Tianjun, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, Li, Zhijin, Nanopoulos, Dimitri V., Astroparticle Physics Group, Houston Advanced Research Center, & Academy of Athens, Division of Natural Sciences, 28 Panepistimiou Avenue, Athens 10679.
```*Symmetry breaking indication for supergravity inflation in light of the Planck 2015*. United States. doi:10.1088/1475-7516/2015/09/006.

```
Li, Tianjun, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, Li, Zhijin, Nanopoulos, Dimitri V., Astroparticle Physics Group, Houston Advanced Research Center, and Academy of Athens, Division of Natural Sciences, 28 Panepistimiou Avenue, Athens 10679. Tue .
"Symmetry breaking indication for supergravity inflation in light of the Planck 2015". United States.
doi:10.1088/1475-7516/2015/09/006.
```

```
@article{osti_22458369,
```

title = {Symmetry breaking indication for supergravity inflation in light of the Planck 2015},

author = {Li, Tianjun and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 and Li, Zhijin and Nanopoulos, Dimitri V. and Astroparticle Physics Group, Houston Advanced Research Center and Academy of Athens, Division of Natural Sciences, 28 Panepistimiou Avenue, Athens 10679},

abstractNote = {Supergravity (SUGRA) theories with exact global U(1) symmetry or shift symmetry in Kähler potential provide natural frameworks for inflation. However, quadratic inflation is disfavoured by the new results on primordial tensor fluctuations from the Planck Collaboration. To be consistent with the new Planck data, we point out that the explicit symmetry breaking is needed, and study these two SUGRA inflation in detail. For SUGRA inflation with global U(1) symmetry, the symmetry breaking term leads to a trigonometric modulation on inflaton potential. Coefficient of the U(1) symmetry breaking term is of order 10{sup −2}, which is sufficient large to improve the inflationary predictions while its higher order corrections are negligible. Such models predict sizeable tensor fluctuations and highly agree with the Planck results. In particular, the model with a linear U(1) symmetry breaking term predicts the tensor-to-scalar ratio around r∼0.01 and running spectral index α{sub s}∼−0.004, which comfortably fit with the Planck observations. For SUGRA inflation with breaking shift symmetry, the inflaton potential is modulated by an exponential factor. The modulated linear and quadratic models are consistent with the Planck observations. In both types of models the tensor-to-scalar ratio can be of order 10{sup −2}, which will be tested by the near future observations.},

doi = {10.1088/1475-7516/2015/09/006},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 09,

volume = 2015,

place = {United States},

year = {Tue Sep 01 00:00:00 EDT 2015},

month = {Tue Sep 01 00:00:00 EDT 2015}

}