Evidence for Planck-scale resonant particle production during inflation from the CMB power spectrum

TL;DR

The paper suggests that a slight dip in the CMB power spectrum may be due to resonant creation of massive particles during inflation, hinting at physics beyond the Planck scale.

Contribution

It proposes a novel interpretation of CMB features as evidence for Planck-scale resonant particle production during inflation.

Findings

Identifies a dip in the CMB power spectrum at multipoles 10-30.

Links the dip to resonant creation of fermions with masses around 8-11 times the Planck mass.

Provides a model connecting the dip to particle creation parameters.

Abstract

The power spectrum of the cosmic microwave background from both the {\it Planck} and {\it WMAP} data exhibits a slight dip for multipoles in the range of $l= 10-30$. We show that such a dip could be the result of the resonant creation of massive particles that couple to the inflaton field. For our best-fit models, the epoch of resonant particle creation reenters the horizon at a wave number of $k_* \sim 0.0011 \pm 0.0004 $ ($h$ Mpc$^{-1}$). The amplitude and location of this feature corresponds to the creation of a number of degenerate fermion species of mass $\sim (8-11) /\lambda^{3/2} $ $m_{pl}$ during inflation where $\lambda \sim (1.0 \pm 0.5) N^{-2/5}$ is the coupling constant between the inflaton field and the created fermion species, while $N$ is the number of degenerate species. Although the evidence is of marginal statistical significance, this could constitute new observational hints of unexplored physics beyond the Planck scale