Gravitational and Cosmological Properties of a Brane-universe
نویسندگان
چکیده
The traditional view on extra-dimensions is the Kaluza-Klein picture: the matter fields live in compact (usually flat) extra-dimensions, and their Fourier expansion along the extra-coordinates lead to an infinite collection of so-called Kaluza-Klein modes, which can be interpreted as four-dimensional fields. Their mass spectrum is very specific since it is discrete with a mass gap of the order of R, where R is the size of the extra dimensions (common for all extra-directions in the simplest cases). The non-observation of Kaluza-Klein modes in present collider experiments therefore provides an upper bound on the size of the extra-dimensions:
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