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

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

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

Authors

Description

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.
12 pages, 4 figures, submitted to PLB