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Title: Drifting oscillations in axion monodromy

In this paper, we study the pattern of oscillations in the primordial power spectrum in axion monodromy inflation, accounting for drifts in the oscillation period that can be important for comparing to cosmological data. In these models the potential energy has a monomial form over a super-Planckian field range, with superimposed modulations whose size is model-dependent. The amplitude and frequency of the modulations are set by the expectation values of moduli fields. We show that during the course of inflation, the diminishing energy density can induce slow adjustments of the moduli, changing the modulations. We provide templates capturing the effects of drifting moduli, as well as drifts arising in effective field theory models based on softly broken discrete shift symmetries, and we estimate the precision required to detect a drifting period. A non-drifting template suffices over a wide range of parameters, but for the highest frequencies of interest, or for sufficiently strong drift, it is necessary to include parameters characterizing the change in frequency over the e-folds visible in the CMB. Finally, we use these templates to perform a preliminary search for drifting oscillations in a part of the parameter space in the Planck nominal mission data.
 [1] ;  [2] ;  [3] ;  [4]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Physics
  2. Cornell Univ., Ithaca, NY (United States). Dept. of Physics
  3. Stanford Univ., CA (United States). Stanford Inst. for Theoretical Physics; SLAC National Accelerator Lab., Menlo Park, CA (United States); Kavli Inst. for Particle Astrophysics and Cosmology, Stanford, CA (United States)
  4. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
Publication Date:
Report Number(s):
Journal ID: ISSN 1475-7516; TRN: US1801057
Grant/Contract Number:
AC02-76SF00515; PHY-0757868; PHY-0756174; PHY11-25915; HZ-NG-603
Accepted Manuscript
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2017; Journal Issue: 10; Journal ID: ISSN 1475-7516
Institute of Physics (IOP)
Research Org:
Cornell Univ., Ithaca, NY (United States); Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
Sponsoring Org:
USDOE; National Science Foundation (NSF); Helmholtz Association of German Research Centres (Germany)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; cosmological parameters from CMBR; inflation; physics of the early universe; string theory and cosmology
OSTI Identifier: