Eur. Phys. J. C (2018) 78: 733
https://doi.org/10.1140/epjc/s10052-018-6218-x

Regular Article - Theoretical Physics

Explaining low anomalies in the CMB power spectrum with resonant superstring excitations during inflation

¹ Department of Physics, Center for Astrophysics, University of Notre Dame, Notre Dame, IN, 46556, USA
² Theory Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata, 700064, India
³ National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588, Japan
⁴ Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
⁵ Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
⁶ International Research Center for Big-Bang Cosmology and Element Genesis, and School of Physics and Nuclear Energy Engineering, Beihang University, Beijing, 100083, China

^* e-mail: mayukh.raj@saha.ac.in

Received: 22 April 2018
Accepted: 31 August 2018
Published online: 12 September 2018

Abstract

We explore the possibility that both the suppression of the multipole moment of the power spectrum of cosmic microwave background temperature fluctuations and the possible dip for –30 can be explained as well as a possible new dip for as the result of the resonant creation of sequential excitations of a fermionic (or bosonic) closed superstring that couples to the inflaton field. We consider a D26 closed bosonic string with one toroidal compact dimension as an illustration of how string excitations might imprint themselves on the CMB. We analyze the existence of successive momentum states, winding states or oscillations on the string as the source of the three possible dips in the power spectrum. Although the evidence of these dips are of marginal statistical significance, this might constitute the first observational evidence of successive superstring excitations in Nature.