Towards the resolution of the e+e- --> Nbar N puzzle
arXiv:hep-ph/0112047 · doi:10.1016/S0920-5632(02)01309-9
Abstract
We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) is somewhat greater than sigma(e+e- --> pbar p). We discuss an interpretation in terms of a two-step process, via an intermediate coherent isovector state serving as an intermediary between e+e- and the baryon-antibaryon system. We provide evidence that the isovector channel dominates both e+e- --> pions and from Nbar N annihilation at rest, and show that the observed ratio of sigma(e+e- --> nbar n)/sigma(e+e- --> pbar p) can be understood quantitatively in this picture.
Invited talk at the Int. Workshop "Light-cone Physics: Particles and Strings", Trento, Sept. 3-11, 2001