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-Soding). 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.
Highlights
Central production mediated by the “fusion” of two exchanged pomerons [1, 2] is an important diffractive process for the investigation of properties of di-pion resonances, in particular, for search of gluonic bound states
Some time ago two of us have formulated a Regge-type model of the dipion continuum for the exclusive reaction pp → ppπ+π− with parameters fixed from phenomenological analysis of total and elastic NN and πN scattering [13]
In [19] we show that the tensor pomeron is consistent with the STAR pp elastic scattering data [20]
Summary
Central production mediated by the “fusion” of two exchanged pomerons [1, 2] is an important diffractive process for the investigation of properties of di-pion resonances, in particular, for search of gluonic bound states (glueballs). The experimental groups such as the COMPASS [3, 4], ISR [5, 6], STAR [7, 8], CDF Tevatron [9], ALICE [10], and CMS [11] all show visible structures in the π+π− invariant mass. Diagram (b): The double-pomeron/reggeon and photon mediated central exclusive scalar and tensor resonance production and their subsequent decays into π+π−. The coupling parameters of tensor pomeron/reggeon exchanges was fixed based on the HERA experimental data for the γp → ρ0 p reaction. Due to the photon propagators occurring in diagrams we expect these processes to be most important when at least one of the protons undergoes only a very small |t1,2|
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
