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Title: Fermion production during and after axion inflation

Abstract

We study derivatively coupled fermions in axion-driven inflation, specifically m{sub φ}{sup 2φ2} and monodromy inflation, and calculate particle production during the inflationary epoch and the post-inflationary axion oscillations. During inflation, the rolling axion acts as an effective chemical potential for helicity which biases the gravitational production of one fermion helicity over the other. This mechanism allows for efficient gravitational production of heavy fermion states that would otherwise be highly suppressed. Following inflation, the axion oscillates and fermions with both helicities are produced as the effective frequency of the fermion field changes non-adiabatically. For certain values of the fermion mass and axion-fermion coupling strength, the two helicity states are produced asymmetrically, resulting in unequal number-densities of left- and right-helicity fermions.

Authors:
Publication Date:
OSTI Identifier:
22525185
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2015; Journal Issue: 11; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AXIONS; COUPLING; DENSITY; FERMIONS; GRAVITATION; HELICITY; MASS; OSCILLATIONS; POTENTIALS

Citation Formats

Adshead, Peter, and Sfakianakis, Evangelos I., E-mail: adshead@illinois.edu, E-mail: esfaki@illinois.edu. Fermion production during and after axion inflation. United States: N. p., 2015. Web. doi:10.1088/1475-7516/2015/11/021.
Adshead, Peter, & Sfakianakis, Evangelos I., E-mail: adshead@illinois.edu, E-mail: esfaki@illinois.edu. Fermion production during and after axion inflation. United States. doi:10.1088/1475-7516/2015/11/021.
Adshead, Peter, and Sfakianakis, Evangelos I., E-mail: adshead@illinois.edu, E-mail: esfaki@illinois.edu. Sun . "Fermion production during and after axion inflation". United States. doi:10.1088/1475-7516/2015/11/021.
@article{osti_22525185,
title = {Fermion production during and after axion inflation},
author = {Adshead, Peter and Sfakianakis, Evangelos I., E-mail: adshead@illinois.edu, E-mail: esfaki@illinois.edu},
abstractNote = {We study derivatively coupled fermions in axion-driven inflation, specifically m{sub φ}{sup 2φ2} and monodromy inflation, and calculate particle production during the inflationary epoch and the post-inflationary axion oscillations. During inflation, the rolling axion acts as an effective chemical potential for helicity which biases the gravitational production of one fermion helicity over the other. This mechanism allows for efficient gravitational production of heavy fermion states that would otherwise be highly suppressed. Following inflation, the axion oscillates and fermions with both helicities are produced as the effective frequency of the fermion field changes non-adiabatically. For certain values of the fermion mass and axion-fermion coupling strength, the two helicity states are produced asymmetrically, resulting in unequal number-densities of left- and right-helicity fermions.},
doi = {10.1088/1475-7516/2015/11/021},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 11,
volume = 2015,
place = {United States},
year = {2015},
month = {11}
}