Simple energy release question

[humsafar]

Simple energy release question...

I've recently checked out a fermilab link which says proton-antiproton annihilation at rest releases only 1.88 GeV energy, but compare this to annihilation at 2 GeV, it releases far far more energy and also "MORE PHOTONS"...WHY?

 

[Meir Achuz]

I've recently checked out a fermilab link which says proton-antiproton annihilation at rest releases only 1.88 GeV energy, but compare this to annihilation at 2 GeV, it releases far far more energy and also "MORE PHOTONS"...WHY?

They mean that the p and anti=p each have 2GeV kinetic energy, so the total energy in the center of momentum system is about 6 GeV.