Vector Meson Photoproduction, Amplittjde Structure and S-channel Iielicity Conservation Viola’i’ion in Pomeron Exchange Reactions”
نویسندگان
چکیده
The experimental &?la on vector meson photoproduction and Compton scattering is analyzed by utilizing the dual absorptive model. The s-channel helicity conserving (SIIC) PO~UXOII exchange amplitude in p” and + photo:>ro&uction is found to shrink with s, in the same way as in Fand K-~-nucleon elastic scattering. The small SEX!-violatjng amplitudzs’are al.so studied. The ratio of amplitudes for 1 MI = 1 to m= 0 at the y-p vertex is shown to be similar to the ratio of correspor;ding TN amplitudes at. the proton vertex and both seem to depend only weakly on s.
منابع مشابه
The Donnachie-landshoff Pomeron and Gauge Invariance
The pomeron model of Donnachie and Landshoff does not conserve the electromagnetic current when applied to diffractive reactions such as electroproduction of a quarkantiquark pair or of a vector meson. We propose a treatment of this problem which ensures a physical behaviour of cross sections in the photoproduction limit and show that it leads to results rather similar to those obtained from tw...
متن کاملDiffraction at Hera
diiractive dissociation at high Q 2. The partonic structure of the pomeron has been measured and found to be dominated by hard gluons. Factorization has been found to be valid within the current sensitivity and measurements range. Figure 34: Results from events with central rapidity gaps, (a) Points before (open circles) and after (full circles) detector corrections. (b) Fit as explained in the...
متن کاملVector Meson Photoproduction in the Quark Model
We present a quark model study of the ω meson photoproduction near threshold. With a limited number of parameters, all the data in history are reproduced. The roles played by the sand u-channel processes (resonance excitations and nucleon pole terms), as well as the t-channel natural (Pomeron) and unnatural parity (pion) exchanges are clarified. This approach provides a framework for systematic...
متن کاملDiffractive Photoproduction of Heavy Vector Mesons
Diffractive vector meson production is described on the one hand within the phenomenological framework based on Regge theory, and on the other hand by perturbative QCD calculations. Light vector mesons in the photoproduction regime (where no hard scale is present) agree well with non-perturbative Regge based descriptions. Perturbative effects are measured in the presence of a hard scale for lig...
متن کاملDiffractive Vector Meson Photoproduction from Dual String Theory
We study diffractive vector meson photoproduction using string theory via AdS/CFT. The large s behavior of the cross sections for the scattering of the vector meson V on a proton is dominated by the soft Pomeron, σV ∼ s2ǫ−2α′P/B, where from the string theory model of [9], ǫ is approximately 1/7 below 10 GeV, and 1/11 for higher, but still sub-Froissart, energies. This is due to the production o...
متن کامل