Backward-angle photoproduction of $π^0$ mesons on the proton at $E_γ$ = 1.5--2.4 GeV

M. Sumihama; J. K. Ahn; H. Akimune; Y. Asano; W. C. Chang; S. Daté; H. Ejiri; H. Fujimura; M. Fujiwara; K. Hicks; T. Hotta; K. Imai; T. Ishikawa; T. Iwata; H. Kawai; Z. Y. Kim; K. Kino; H. Kohri; N. Kumagai; S. Makino; T. Matsumura; N. Matsuoka; T. Mibe; M. Miyabe; 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. Sato; P. M. Shagin; Y. Shiino; H. Shimizu; Y. Sugaya; H. Toyokawa; A. Wakai; C. W. Wang; S. C. Wang; K. Yonehara; T. Yorita; M. Yosoi; R. G. T. Zegers

doi:10.1016/j.physletb.2007.10.032

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arXiv · 0708.1600

Backward-angle photoproduction of $π^0$ mesons on the proton at $E_γ$ = 1.5--2.4 GeV

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Abstract

Differential cross sections and photon beam asymmetries for $π^0$ photoproduction have been measured at $E_γ$ = 1.5--2.4 GeV and at the $π^0$ scattering angles, --1 $<$ cos$Θ_{c.m.} <$ --0.6. The energy-dependent slope of differential cross sections for $u$-channel $π^0$ production has been determined. An enhancement at backward angles is found above $E_γ$ = 2.0 GeV. This is inferred to be due to the $u$-channel contribution and/or resonances. Photon beam asymmetries have been obtained for the first time at backward angles. A strong angular dependence has been found at $E_γ>$ 2.0 GeV, which may be due to the unknown high-mass resonances.

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M. Sumihama, J. K. Ahn, H. Akimune, Y. Asano, W. C. Chang, S. Daté, H. Ejiri, H. Fujimura, M. Fujiwara, K. Hicks, T. Hotta, K. Imai, T. Ishikawa, T. Iwata, H. Kawai, Z. Y. Kim, K. Kino, H. Kohri, N. Kumagai, S. Makino, T. Matsumura, N. Matsuoka, T. Mibe, M. Miyabe, 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. Sato, P. M. Shagin, Y. Shiino, H. Shimizu, Y. Sugaya, H. Toyokawa, A. Wakai, C. W. Wang, S. C. Wang, K. Yonehara, T. Yorita, M. Yosoi, R. G. T. Zegers. 2007-08-12. Backward-angle photoproduction of $π^0$ mesons on the proton at $E_γ$ = 1.5--2.4 GeV. https://doi.org/10.1016/j.physletb.2007.10.032

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