Kaluza-Klein Mode Emission Into Extra Dimensions

(lores animated gif version. for higher quality, follow the links below

It is possible that we live in a world that has more than the usual 1 time + 3 space dimensional world of everyday life experience. Indeed, one way to explain the peculiar properties of gravity is that the universe inhabits 4+n dimensional space (the Bulk) while we are trapped to live in the familiar 4 dimensional world (the Brane).

The movie shown here illustrates a process that might occur in such a scenario. The bulk here is shown as the big black void containing our brane, which is the represented by the box grid populated by galaxies, stars and familiar elementary particles.

Two such particles, for example a proton and an antiproton, shown as generic blue balls, can collide on the brane and if the energy is high enough, produce a graviton (particle that mediates the force of gravity on the brane), an array of familiar elementary particles (all shown as generic blue balls) and a Kaluza-Klein mode (a particle that lives in the bulk) which flies out of the brane. The graviton is the only particle that couples to the curvature of space-time and here it is shown as a ripple of the space-time grid.

An observer on the brane witnessing the outcome of the collision would see the usual particles produced in such experiments, a graviton (if she is lucky and capable of detecting gravitons, which so far no one has been able to do) and missing energy attributed to the Kaluza-Klein mode. The only way to infer the existence of the Kaluza-Klein mode would be to demonstrate its definite absence on our brance.

Created by Liubo Borissov working under the commission, guidance and inspiration of Joe Lykken. For questions/comments feel free to contact liubo@fnal.gov. This material is copyleft and available freely. You can download the movie as hi-res quicktime (10Mb), broadcast quality quicktime (30Mb) or flash (16 Mb). You may also want to see a short documentory I made about detectors available here .