Double pomeron exchange in the reaction pp→ppπ+π-

The cross section for pp→ppπ+π- in the kinematical region for which two-pomeron exchange is important, assuming dominance of the pion-exchange pole is computed. Effects due to absorption, final-state interaction, and interference between the two contributing Feynman diagrams are included. These effects have been ignored in previous calculations. Consequently, the predicted cross section is smaller than previous predictions by a factor of approximately 3, and is consistent with experimental indications. The background cross section in the double pomeron exchange region is calculated and it is found that it is sizable even at s approximately 3000 GeV2. The two-particle inclusive process pp→ppX is discussed. (Auth.)