[Physicist]

Extra-dimension models in general imply higher-mode graviton resonances, corresponding to non-ground-state excitations of a graviton's Schrödinger wave function. In the (massless) ground state, one half of a graviton's Schrödinger wavelength would fit along the (invisible, orthogonal) extra dimension. (You know, the old particle-in-a-box problem from chapter 2 of whatever quantum textbook you use.) This implies the existence of a state where a full wavelength fits along that dimension, and another state with one and a half, etc. If a graviton could be kicked into one of these states by, say, a powerful enough particle collision, it would carry a momentum component along the hidden direction, which would manifest itself in our space as a mass (let the graviton itself be ever so massless in 5-dimensional reality). So as you increase the collision energy, you would see a series of gigantic resonances, occurring at the effective (i.e. 4-dimensional) masses of these states.

[RightWingAtheist]

Thanks, guys!

[grey_whiskers]

Sorry, came upon this thread *very* late whilst looking for something else.

What is the shape of the potential well comprising the "box" in the invisible, orthogonl dimension? Is it shaped in any way so as to allow for tunneling, or are the barriers too wide and steep for that?

Cheers!