# What is $\gamma$$\rho$ mixing?

In a previous question, I asked about the apparent universality behaviour in hadron elastic scattering. I was particularly shocked to see that even $$\gamma p$$ showed that universal behaviour with respect the COM energy $$s$$. This can be seen in slides 35 and 36 in this presentation by Kazunori Itakura, Basics of Pomerons and Reggeons (NB: PDF)

As an explanation I received a vague statement about $$\gamma\rho$$ mixing which I do not understand. Could anybody try to explain and provide some references that I can study?

I apologize for asking over and over again, but it seems that Regge Theory is not a popular theory and I have nobody to ask when something puzzles me. Please believe me, I am totally uninterested in "reputation", "badges" and so on.

It is hard for me to believe that a photon is, in reality, a mixed state of a pure EM photon and a vector meson, as suggested in the comments. One of the referenced sources seems to indicate that it is just an effective model.

Could $$\gamma\rho$$ mixing be explained as a high energy renormalization effect induced by virtual quark-antiquark loops? This could be pure nonsense and I apologyze for it in advance in case it is.

• it is basically lost science and knowledge, traditional academics and the "pimp the publishing metrics to get tenure" does not encourage at all keeping around human experience in theories that are not being actively pursued by the communities – lurscher Sep 7 '18 at 12:47
• @lurscher It's so bad I think I gave a conference presentation involving Pomerons (and vector mesons), but I can't even remember where or when, or what was is in (other the rhos). – JEB Sep 7 '18 at 13:15
• @lurscher and JEB. Neither of you are being particularly helpful. Regge theory is the only model that explains the $pp$ and $p\bar p$ elastic scattering experimental data. If it became outmoded at some stage, I can assure you that it's coming back and there are many people trying to learn it. But not explaining anything and not providing references (which you're, of course, free not to do if that's what you wish) does not make things any better. – Carlos L. Janer Sep 7 '18 at 13:30
• – Cosmas Zachos Sep 8 '18 at 8:30
• – Cosmas Zachos Sep 8 '18 at 8:33