Flavour structure of low-energy hadron pair photoproduction

K. Odagiri; R. C. Verma

doi:10.1140/epjc/s10052-007-0337-0

paper

Flavour structure of low-energy hadron pair photoproduction

arXiv:hep-ph/0508114 · doi:10.1140/epjc/s10052-007-0337-0

Abstract

We consider the process $γ γ \to H_{1} H ˉ_{2}$ where $H_{1}$ and $H_{2}$ are either mesons or baryons. The experimental findings for such quantities as the $p p ˉ$ and $K_{S} K_{S}$ differential cross sections, in the energy range currently probed, are found often to be in disparity with the scaling behaviour expected from hard constituent scattering. We discuss the long-distance pole--resonance contribution in understanding the origin of these phenomena, as well as the amplitude relations governing the short-distance contribution which we model as a scaling contribution. When considering the latter, we argue that the difference found for the $K_{S} K_{S}$ and the $K^{+} K^{-}$ integrated cross sections can be attributed to the s-channel isovector component. This corresponds to the $ρ ω \to a$ subprocess in the VMD (vector-meson-dominance) language. The ratio of the two cross sections is enhanced by the suppression of the $ϕ$ component, and is hence constrained. We give similar constraints to a number of other hadron pair production channels. After writing down the scaling and pole--resonance contributions accordingly, the direct summation of the two contributions is found to reproduce some salient features of the $p p ˉ$ and $K^{+} K^{-}$ data.

arXiv comment12 pages, 9 figures, revised version to be published in EPJC

Flavour structure of low-energy hadron pair photoproduction

Abstract

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