Physics – High Energy Physics – High Energy Physics - Theory
Scientific paper
2007-09-24
JCAP0804:001,2008
Physics
High Energy Physics
High Energy Physics - Theory
65 pages, 15 figures, uses iopart. Shortened version, updated references. Matches publication up to appendix B kept on the arX
Scientific paper
10.1088/1475-7516/2008/04/001
The Wilkinson Microwave Anisotropy Probe (WMAP) constraints on string inspired ''brane inflation'' are investigated. Here, the inflaton field is interpreted as the distance between two branes placed in a flux-enriched background geometry and has a Dirac-Born-Infeld (DBI) kinetic term. Our method relies on an exact numerical integration of the inflationary power spectra coupled to a Markov-Chain Monte-Carlo exploration of the parameter space. This analysis is valid for any perturbative value of the string coupling constant and of the string length, and includes a phenomenological modelling of the reheating era to describe the post-inflationary evolution. It is found that the data favour a scenario where inflation stops by violation of the slow-roll conditions well before brane annihilation, rather than by tachyonic instability. Concerning the background geometry, it is established that log(v) > -10 at 95% confidence level (CL), where "v" is the dimensionless ratio of the five-dimensional sub-manifold at the base of the six-dimensional warped conifold geometry to the volume of the unit five-sphere. The reheating energy scale remains poorly constrained, Treh > 20 GeV at 95% CL, for an extreme equation of state (wreh ~ -1/3) only. Assuming the string length is known, the favoured values of the string coupling and of the Ramond-Ramond total background charge appear to be correlated. Finally, the stochastic regime (without and with volume effects) is studied using a perturbative treatment of the Langevin equation. The validity of such an approximate scheme is discussed and shown to be too limited for a full characterisation of the quantum effects.
Lorenz Larissa
Martin Jerome
Ringeval Christophe
No associations
LandOfFree
Brane inflation and the WMAP data: a Bayesian analysis does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Brane inflation and the WMAP data: a Bayesian analysis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brane inflation and the WMAP data: a Bayesian analysis will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-276860