Cross section energy dependence

[kaksmet]

Hey,

The hard cross-section of a 2 to 2 inelastic scattering goes as 1/E^2, where E is the center of mass energy. However, the cross-section in proton proton collisions increases with energy.
My question is; does anybody have a good explanation for this and/or a good reference where I can read about it.

Thanks
T

 

[earth2]

Concerning the increasing crosssection bit, there is a nice book by Forshaw and Ross called "Pomeron something something" (sorry, forgot the full title). Alternatively check http://arxiv.org/abs/hep-ph/9503226

Hope i could help!
earth2

 

[Drakkith]

I'm assuming the cross section increases with energy because protons repel each other. The more energy they have the less they are deflected per time/distance.

 

[earth2]

I'm assuming the cross section increases with energy because protons repel each other. The more energy they have the less they are deflected per time/distance.

Does that even make sense on physical grounds? In any case it is not true since the cross section of pp collisions and ppbar collision is the same at high energies, so your argument breaks down.

Without being able to reproduce the full explanation, i think i remember that the increase has something to do with the "reggezation" of the gluons being exchanged in that collision...as i said i can't reproduce the argument but there should be something in the two reference i mentionened in my first posting.

 

[Drakkith]

Does that even make sense on physical grounds? In any case it is not true since the cross section of pp collisions and ppbar collision is the same at high energies, so your argument breaks down.

Without being able to reproduce the full explanation, i think i remember that the increase has something to do with the "reggezation" of the gluons being exchanged in that collision...as i said i can't reproduce the argument but there should be something in the two reference i mentionened in my first posting.

Oh, I had no idea. I was throwing out a guess based on my understanding that protons repel each other, and I would think that with higher energies the cross section would increase. I assumed that the protons that didn't collide at lower energies might collide at higher energies because they are able to get closer without being pushed away as far. Sorry, I have a tendency to stick my nose into things I don't really know about lol.