Normalization discrepancies in photoproduction reactions

Recent CLAS photoproduction results using a tagged bremsstrahlung photon beam for the ground-state pseudoscalar meson photoproduction channels ($K^+ Λ$, $K^+ Σ^0$, $ηp$, $π^+ n$ and $π^0 p$) show a normalization discrepancy with older results from SLAC, DESY and CEA that used an untagged bremsstrahlung beam. The CLAS results are roughly a factor of two smaller than the older data. The CLAS $K^+Λ$ and $K^+Σ^0$ results are in excellent agreement with the latest LEPS results that also employed a tagged beam. For the vector meson ($ωp$ and $ϕp$) channels, CLAS agrees with SLAC results that employed a linearly polarized beam using laser back-scattering, as well as Daresbury data that also came from tagged photon experiment. We perform a global survey of these normalization issues and stress on their significant effect on the coupling constants used in various partial wave analyses.

No reviews yet.

No comments yet.