“…If regions of rapidity exceeding about 5 units are devoid of particles, only photon and pomeron [2], IP , exchanges are significant, where IP consists mostly of two gluons in a color singlet state with charge parity C = +1. Odderon, O, exchange, with 3 gluons in a C = −1 state [3,4,5], is allowed in pp, but not ep, collisions, and would appear as an enhancement in exclusive J/ψ and ψ(2S) production in pp compared to the expectation from pure photoproduction in ep. Using the CDF II detector at the Fermilab Tevatron, we previously observed [6] p +p → p + e + e − +p in agreement with QED, and found candidates [7] for p +p → p + γγ +p consistent with QCD expectations [8].…”