Clockwork axions in cosmology. Is chromonatural inflation chrononatural?
Abstract
Many cosmological models rely on large couplings of axions to gauge fields. Examples include theories of magnetogenesis, inflation on a steep potential, chiral gravitational waves, and chromonatural inflation. Such theories require a mismatch between the axion field range and the mass scale appearing in the aF\tilde{F} coupling. This mismatch suggests an underlying monodromy, with the axion winding around its fundamental period a large number of times. We investigate the extent to which this integer can be explained as a product of smaller integers in a UV completion: in the parlance of our times, can the theory be "clockworked"? We argue that a clockwork construction producing a potential {μ}^4 cos (a/j{F_a}) for an axion of fundamental period F a will obey the constraint μ < F a . For a some applications, including chromonatural inflation with sub-Planckian field range, this constraint obstructs a clockwork UV completion. Alternative routes to a large coupling include fields of large charge (an approach limited by strong coupling) or kinetic mixing (requiring a lighter axion). Our results suggest that completions of axion cosmologies that explain the large parameter in the theory potentially alter the phenomenological predictions of the model.
- Publication:
-
Journal of High Energy Physics
- Pub Date:
- October 2018
- DOI:
- 10.1007/JHEP10(2018)193
- arXiv:
- arXiv:1806.09621
- Bibcode:
- 2018JHEP...10..193A
- Keywords:
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- Anomalies in Field and String Theories;
- Cosmology of Theories beyond the SM;
- High Energy Physics - Theory;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- High Energy Physics - Phenomenology
- E-Print:
- doi:10.1007/JHEP10(2018)193