In physics, the pomeron is a Regge trajectory — a family of particles with increasing spin — postulated in 1961 to explain the slowly rising cross section of hadronic collisions at high energies.
[citation needed] The identification of the pomeron and the prediction of its properties was a major success of the Regge theory of strong interaction phenomenology.
[citation needed] The modern interpretation of Pomeranchuk's theorem is that the pomeron has no conserved charges—the particles on this trajectory have the quantum numbers of the vacuum.
In high energy proton–proton and proton–antiproton collisions in which it is believed that pomerons have been exchanged, a rapidity gap is often observed: This is a large angular region in which no outgoing particles are detected.
[citation needed] The odderon, the counterpart of the pomeron that carries odd charge parity, was introduced in 1973 by Leszek Łukaszuk and Basarab Nicolescu.