Study of double pomeron exchange in pp collisions at √s=31GeV☆

Abstract The reaction pp→pp π + π − at √ s =31GeV was studied at the Split Field Magnet Facility of the CERN-ISR. Selecting events with two leading protons of x >0.9 and a rapidity gap Δy >2 between the protons and both pions a sample of 720 events is obtained representing a cross section of 25±10 μb . The mass distribution of the dipion system, x and p T distributions for the protons are presented and analyzed for the presence of double pomeron exchange.