Forward coherent $ϕ$-meson photoproduction from deuterons near threshold

W. C. Chang; K. Horie; S. Shimizu; M. Miyabe; D. S. Ahn; J. K. Ahn; H. Akimune; Y. Asano; S. Date; H. Ejiri; S. Fukui; H. Fujimura; M. Fujiwara; S. Hasegawa; K. Hicks; T. Hotta; K. Imai; T. Ishikawa; T. Iwata; Y. Kato; H. Kawai; Z. Y. Kim; K. Kino; H. Kohri; N. Kumagai; P. J. Lin; S. Makino; T. Matsuda; T. Matsumura; N. Matsuoka; T. Mibe; Y. Miyachi; M. Morita; N. Muramatsu; T. Nakano; M. Niiyama; M. Nomachi; Y. Ohashi; H. Ohkuma; T. Ooba; D. S. Oshuev; C. Rangacharyulu; A. Sakaguchi; T. Sasaki; P. M. Shagin; Y. Shiino; A. Shimizu; H. Shimizu; Y. Sugaya; M. Sumihama; Y. Toi; H. Toyokawa; A. Wakai; C. W. Wang; S. C. Wang; K. Yonehara; T. Yorita; M. Yoshimura; M. Yosoi; R. G. T. Zegers

doi:10.1016/j.physletb.2007.11.009

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Forward coherent $ϕ$-meson photoproduction from deuterons near threshold

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Abstract

Differential cross sections and decay asymmetries for coherent $ϕ$-meson photoproduction from deuterons were measured for the first time at forward angles using linearly polarized photons at $E_γ$= 1.5-2.4 GeV. This reaction offers a unique way to directly access natural-parity Pomeron dynamics and gluon exchange at low energies. The cross sections at zero degrees increase with increasing photon energy. The decay asymmetries demonstrate a complete dominance of natural-parity exchange processes, showing that isovector unnatural-parity $π$-meson exchange is small. Nevertheless the deduced cross sections of $ϕ$-mesons from nucleons contributed by isoscalar t-channel exchange processes are not well described by the conventional Pomeron model.

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W. C. Chang, K. Horie, S. Shimizu, M. Miyabe, D. S. Ahn, J. K. Ahn, H. Akimune, Y. Asano, S. Date, H. Ejiri, S. Fukui, H. Fujimura, M. Fujiwara, S. Hasegawa, K. Hicks, T. Hotta, K. Imai, T. Ishikawa, T. Iwata, Y. Kato, H. Kawai, Z. Y. Kim, K. Kino, H. Kohri, N. Kumagai, P. J. Lin, S. Makino, T. Matsuda, T. Matsumura, N. Matsuoka, T. Mibe, Y. Miyachi, M. Morita, N. Muramatsu, T. Nakano, M. Niiyama, M. Nomachi, Y. Ohashi, H. Ohkuma, T. Ooba, D. S. Oshuev, C. Rangacharyulu, A. Sakaguchi, T. Sasaki, P. M. Shagin, Y. Shiino, A. Shimizu, H. Shimizu, Y. Sugaya, M. Sumihama, Y. Toi, H. Toyokawa, A. Wakai, C. W. Wang, S. C. Wang, K. Yonehara, T. Yorita, M. Yoshimura, M. Yosoi, R. G. T. Zegers. 2008-01-03. Forward coherent $ϕ$-meson photoproduction from deuterons near threshold. https://doi.org/10.1016/j.physletb.2007.11.009

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