A stringy mechanism for a small cosmological constant — multimoduli cases
Abstract
Based on the properties of probability distributions of functions of random variables, we proposed earlier a simple stringy mechanism that prefers the metastable vacua with a small cosmological constant Λ. As an illustration of this approach, we study in this paper particularly simple but nontrivial models of the Kähler uplift in the large volume flux compactification scenario in Type IIB string theory, where all parameters introduced in the model are treated either as fixed constants motivated by physics, or as random variables with some given uniform probability distributions. We determine the value w_{0} of the superpotential W_{0} at the supersymmetric minima, and find that the resulting probability distribution P(w_{0}) peaks at w_{0} = 0; furthermore, this peaking behavior strengthens as the number of complex structure moduli increases. The resulting probability distribution P(Λ) for metastable vacua also peaks as Λ → 0, for both positive and negative Λ. This peaking/divergent behavior of P(Λ) strengthens as the number of moduli increases. In some scenarios for Λ > 0, the likely value of Λ decreases exponentially as the number of moduli increases. The light cosmological moduli issue accompanying a very small Λ is also mentioned.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 February 2013
 DOI:
 10.1088/14757516/2013/02/006
 arXiv:
 arXiv:1209.5086
 Bibcode:
 2013JCAP...02..006S
 Keywords:

 High Energy Physics  Theory;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Phenomenology
 EPrint:
 34+11 pages, 45 figures