Exclusive central diffractive production of scalar and pseudoscalar mesons; tensorial vs. vectorial pomeron

Abstract

We discuss consequences of the models of "tensorial pomeron" and "vectorial pomeron" for exclusive diffractive production of scalar and pseudoscalar mesons in proton-proton collisions. Diffractive production of f 0 (980), f 0 (1370), f 0 (1500), η, and η ′ (958) mesons is discussed. Different pomeronpomeron-meson tensorial coupling structures are possible in general. In most cases two lowest orbital angular momentum -spin couplings are necessary to describe experimental differential distributions. For f 0 (980) and η production reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data. Correlations in azimuthal angle between outgoing protons, distributions in rapidities and transverse momenta of outgoing protons and mesons, in a special "glueball filter variable", as well as some two-dimensional distributions are presented. We discuss differences between results of the vectorial and tensorial pomeron models. We show that high-energy central production, in particular of pseudoscalar mesons, could provide crucial information on the spin structure of the soft pomeron.

Witten-Veneziano mechanism and pseudoscalar glueball-meson mixing in holographic QCD

“…Up to partial integrations, the tensorial structure of the two terms in (5.1) is in fact in one-to-one correspondence to the two couplings g PPM and g PPM for two tensor pomerons with one pseudoscalar meson in[58].…”

Diffractive Physics at the LHC

“…Exclusive pions can also be produced via resonances, e.g. f 0 [18]. Although the dominant diagram of the exclusive pion pair continuum production is a Pomeron-induced one, the production of a photoninduced continuum is also possible.…”

Tensor Pomeron and low- x deep inelastic scattering

“…In [11] the tensor pomeron was introduced for soft reactions and many of its properties were derived from comparisons with experiment. Further applications of the tensorpomeron concept were given for photoproduction of pion pairs in [13] and for a number of exclusive central-production reactions in [14,15,16,17,18,19,20]. In [21] the helicity structure of small-|t| proton-proton elastic scattering was calculated in three models for the pomeron: tensor, vector, and scalar.…”