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Natural inflation, strong dynamics, and the role of generalized anomalies

Anber, Mohamed M. and Baker, Stephen (2020) 'Natural inflation, strong dynamics, and the role of generalized anomalies.', Physical Review D, 102 (10). p. 103515.


We revisit models of natural inflation and show that the single-field effective theory described by the potential V ( a ) ∼ cos a f breaks down as the inflaton a makes large-field excursions, even for values of f smaller than the Planck scale. To remedy the problem, we modify the potential in order to account for the heavy degrees of freedom (hadrons) that become intertwined with the light inflaton as the latter rolls down its potential. By embedding the low-energy degrees of freedom into an ultraviolet-complete gauge theory, we argue that the intertwining between the two scales can be explained as the result of a generalized mixed ’t Hooft anomaly between the discrete chiral symmetry and background fractional fluxes in the baryon number, color, and flavor directions. Further, we study the multifield inflation and show that it entertains rich dynamics. Inflating near the hilltop excites the hadrons and spoils the slow-roll parameters, in contradistinction with the expectations in the single-field inflation. Nevertheless, we identify a safe zone where inflation can proceed successfully. We determine the conditions under which the Universe inflates by at least 60 e -foldings and inflation leads to a power spectrum and tensor to scalar ratio that are consistent with the cosmic microwave background data.

Item Type:Article
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Publisher statement:Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Date accepted:13 October 2020
Date deposited:04 October 2021
Date of first online publication:13 November 2020
Date first made open access:04 October 2021

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