Statistical Approach to the Cosmological-Constant Problem on Brane Worlds

TL;DR

This paper analyzes braneworld models to determine the likelihood of small versus large cosmological constants, finding that small values are statistically favored across the parameter space.

Contribution

It provides a statistical analysis of solutions in braneworld scenarios, showing the natural tendency toward small effective cosmological constants without additional assumptions.

Findings

Solutions with small Hubble parameters are more probable.

The distribution of solutions tends to a delta function for continuous parameter coverage.

Small cosmological constants are statistically favored in the model.

Abstract

We investigate the physically accepted solutions of general Braneworld scenarios, scanning uniformly the associated parameter space. Without making any further assumptions we find that solutions which give "small" Hubble parameters on the physical brane, and therefore "small" effective cosmological constants on the 4D Universe, are far more probable than those with "large" ones. Eventually, their distribution tends to the $\delta$-function in the limit of continuous covering of the parameter space.