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arXiv · 1103.3821

Differential cross sections and spin density matrix elements for gamma p -> phi p from CLAS

Biplab Dey·Curtis A. Meyer
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Abstract

Preliminary differential cross-sections and the $ρ^0_{MM'}$ spin density matrix elements (SDME) for the reaction $γp \to ϕp$ for both charged- ($ϕ\to K^+ K^-$) and neutral-mode ($ϕ\to K^0_L K^0_S$) topologies obtained from CLAS are presented. Our kinematic coverage is from near production threshold ($\sqrt{s} \sim 1.97$ GeV) to $\sqrt{s} = 2.84$ GeV, with a wide coverage in the production angle. As seen in previous LEPS results, the differential cross-sections show a localized "bump" between $\sqrt{s} \sim 2$ and 2.2 GeV that is not expected from a simple Pomeron exchange picture. Comparisons between the charged- and neutral-mode results and possible effects from the $K^+ Λ(1520)$ channel are discussed. Our SDME results confirm the well-known deviations from t-channel helicity conservation (TCHC) for Pomeron exchange, but s-channel helicity conservation (SCHC) is also seen to be broken.

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Biplab Dey, Curtis A. Meyer. 2011-03-31. Differential cross sections and spin density matrix elements for gamma p -> phi p from CLAS. https://doi.org/10.1063/1.3647381

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