Exclusive diffractive production ofπ⁺π⁻continuum and resonances within tensor pomeron approach

Abstract

Abstract. We discuss exclusive central diffractive dipion production in proton-(anti)proton collisions at high energies. The calculation is based on a tensor pomeron model and the amplitudes for the processes are formulated in an effective field-theoretic approach. We include the purely diffractive dipion continuum, and the scalar and tensor resonances decaying into the π + π − pairs as well as the photoproduction contributions (ρ 0 , Drell-Söding). We discuss how two pomerons couple to tensor meson f 2 (1270) and the interference effects of resonance and dipion continuum. The theoretical results are compared with CDF and CMS experimental data. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions for outgoing particles. We find that the relative contribution of resonant f 2 (1270) and dipion continuum strongly depends on the cut on proton transverse momenta (or four-momentum transfer squared t 1,2 ) which may explain some controversial observations made by different ISR experiments in the past. The cuts may play then the role of a ππ resonance filter. We suggest some experimental analyses to fix model parameters related to the pomeron-pomeron-meson coupling.

Central exclusive diffractive production of two-pions from continuum and decays of resonances in the Regge-eikonal model

“…, where p denotes the momenta of final protons. Curves correspond to Λ π = 1 GeV in the off-shell pion form factor (9) and couplings from (12). Solid curves correspond to the sum of all amplitudes and the dotted one in (a) represents the continuum contribution.…”

“…g PPf0(500) = 0.77, 9) and couplings from (12). Solid curves correspond to the sum of all amplitudes and dotted ones represent the continuum contribution.…”

“…In Fig. 11 one can see the recent data from the CMS collaboration and curves of our model, which correspond to Λ π = 1 GeV in the off-shell pion form factor (9) and couplings (12) from the fit to the STAR data on Fig. 6.…”

“…In our approach we have several free parameters: Λ π (for the continuum) and couplings of resonances to Pomeron g PPf , which we can extract from the data. All the distributions are depicted here for Λ π = 1 GeV and couplings from (12). , where p denotes the momenta of final protons.…”

“…, where p denotes the momenta of final protons. Theoretical solid curve correspond to Λ π = 1 GeV in the off-shell pion form factor (9) and couplings from (12). Fluctuations are due to complex Monte-Carlo integration process, and they can be smoothed by increasing the integration accuracy.…”