exclusive pipi production in proton-proton collisions at 7 tev

The exclusive production of charged pions, are reported in the proton-proton collisions, where the π+π- pair is emitted at the central rapidity, y, and the scattered protons stay intact (p) without detection. This measurement is performed with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 450 μb-1 collected at a center-of-mass energy of  7 TeV. The dipion cross section, measured for single-pion transverse momentum pT > 0.2 GeV/c and rapidity |y| < 2, is 20.5 ± 0.3 (stat) ± 3.1 (syst) ± 0.8 (lumi) μb. The differential cross sections as a function of π+π- invariant mass, is compared to phenomenological predictions.