Testing the existence of higher dimensions

[bascule]

http://www.physorg.com/news67773542.html

 

Yay!

[timo]

Tests for models with additional dimensions are far from being new. Whether astrophysical tests are something new of whether it´s just yet another testing idea I cannot tell.

[SmallIsPower]

I have read of a handful of partial tests, it's good to see another come down the pike. Relativity has survived lots of challenges, odds are it will survive this one.

[Bettina]

I can't wait

 

http://seattlepi.nwsource.com/books/271955_stringtheory29.html

 

Bee

[Severian]

The LHC should answer this question much sooner.

[Martin]

http://www.physorg.com/news67773542.html

 

Yay!

might be good to be a little wary

here is the paper they are talking about

http://arxiv.org/abs/gr-qc/0603061

 

it compares standard 4D Gen Rel with a 5D Randall-Sundrum model

 

(that is' date=' one extra dimension)

 

but it does not make the 5D model actually falsifiable because the R-S model does not say HOW ABUNDANT these little black holes are. their abundance depends on an undetermined parameter. This protects Randall-Sundrum. The 5D model is NOT ACTUALLY AT RISK!

 

In other words if they ask GLAST to look for gammaray fringes (evidence of a tiny black hole that just happened to be between the gamma source and us) and they do NOT find these fringes, then unfortunately it does not shoot down the Randall-Sundrum model.

 

it might be that the R-S model is still valid, but the tiny black holes are not sufficiently abundant. maybe you have to be incredibly lucky to see these fringes because the tiny holes are so rare.

 

(the popularized account makes it more newsworthy and appealing by having the guys sound more confident of having a good test then they actually are in the peer-reviewed publishable paper---which is not too unusual)

 

I tend not to think of it as a rigorous test (at least of R-S) because the 5D R-S model is still made not falsifiable. No new theory is betting its life on seeing fringes. On the other hand if next year we actually DO see diffraction fringes of the gammaray having passed right by a tiny black hole and if we deduce, say, that the solar system is swarming with tiny black holes, that would be extremely interesting. My impression anyway. Havent thought it through a lot.

 

Hmmmm you could say that it is actually [b']Gen Rel[/b] that is being tested! Because if they see fringes it would tend to discredit Gen Rel----the classical theory does not tell us that the solar system is swarming with tiny black holes.

 

As they say in the publicity piece, if fringes were observed this would "disfavor" Gen Rel.

So I think, by the scientists' own words, that it is the standard classical gravity theory that is running the risk, this time.

 

Gen Rel. is also put at risk by observations that confirm the Pioneer anomaly.

 

To me, it isnt clear what alternative would gain credence (there can always be alternative explanations put forth). Interesting situation and at least SOMETHING IS TESTING SOMETHING, but not clear-cut.

[ajb]

This paper might be of interest. It is an introduction to the subject and does talk about experiments.

 

http://arxiv.org/abs/hep-ph/0606153

[ajb]

Here is another paper on the archive that might be of interest

 

http://arxiv.org/abs/hep-th/0606194