English

Testing String Theory with CMB

High Energy Physics - Theory 2009-11-13 v1 Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology

Abstract

Future detection/non-detection of tensor modes from inflation in CMB observations presents a unique way to test certain features of string theory. Current limit on the ratio of tensor to scalar perturbations, r=T/S, is r < 0.3, future detection may take place for r > 10^{-2}-10^{-3}. At present all known string theory inflation models predict tensor modes well below the level of detection. Therefore a possible experimental discovery of tensor modes may present a challenge to string cosmology. The strongest bound on r in string inflation follows from the observation that in most of the models based on the KKLT construction, the value of the Hubble constant H during inflation must be smaller than the gravitino mass. For the gravitino mass in the usual range, m_{3/2} < O(1) TeV, this leads to an extremely strong bound r < 10^{-24}. A discovery of tensor perturbations with r > 10^{-3} would imply that the gravitinos in this class of models are superheavy, m_{3/2} > 10^{13} GeV. This would have important implications for particle phenomenology based on string theory.

Keywords

Cite

@article{arxiv.0704.0647,
  title  = {Testing String Theory with CMB},
  author = {Renata Kallosh and Andrei Linde},
  journal= {arXiv preprint arXiv:0704.0647},
  year   = {2009}
}

Comments

13 pages, 2 figures