Uehara, S.Watanabe, Y.Nakazawa, H.Adachi, I.Aihara, H.Arinstein, K.Aulchenko, V.Bakich, A.M.Belous, K.Bondar, A.Bračko, M.Browder, T.E.Chang, P.Chen, A.Cheon, B.G.Chistov, R.Choi, Y.Crnkovic, J.Dalseno, J.Dash, M.Eidelman, S.Epifanov, D.Gabyshev, N.Garmash, A.Goldenzweig, P.Ha, H.Hayasaka, K.Hayashii, H.Horii, Y.Hoshi, Y.Hou, W.-S.Hyun, H.J.Iijima, T.Inami, K.Ishikawa, A.Itoh, R.Iwasaki, M.Iwasaki, Y.Kang, J.H.Kawai, H.Kichimi, H.Kiesling, C.Kim, H.O.Kim, J.H.Kim, Y.I.Kim, Y.J.Ko, B.R.Krokovny, P.Kumar, R.Kuzmin, A.Kwon, Y.-J.Kyeong, S.-H.Lee, S.-H.Li, J.Limosani, A.Liu, C.Liventsev, D.Louvot, R.Matyja, A.McOnie, S.Miyabayashi, K.Miyata, H.Miyazaki, Y.Mizuk, R.Mori, T.Nagasaka, Y.Nakano, E.Nakao, M.Nishida, S.Nishimura, K.Nitoh, O.Ogawa, S.Ohshima, T.Okuno, S.Palka, H.Park, C.W.Park, H.Park, H.K.Poluektov, A.Sahoo, H.Sakai, Y.Schneider, O.Schwanda, C.Senyo, K.Sevior, M.E.Shapkin, M.Shebalin, V.Shen, C.P.Shiu, J.-G.Shwartz, B.Singh, J.B.Sokolov, A.Stanič, S.Starič, M.Sumiyoshi, T.Taylor, G.N.Teramoto, Y.Unno, Y.Uno, S.Urquijo, P.Usov, Y.Varner, G.Vervink, K.Vinokurova, A.Wang, C.H.Wang, P.Wedd, R.Won, E.Yamashita, Y.Zhang, C.C.Zhang, Z.P.Zhilich, V.Zhulanov, V.Zivko, T.Zupanc, A.Zyukova, O.2010-11-052010-11-052010-11-05200910.1103/PhysRevD.80.0320012-s2.0-69549095608https://infoscience.epfl.ch/handle/20.500.14299/56839WOS:000269641100008The differential cross section for the process γγ→η π0 has been measured in the kinematic range 0.84GeV<W<4.0GeV, θ*|<0.8, where W and θ* are the energy and π0 (or η) scattering angle, respectively, in the γγ center-of-mass system. The results are based on a 223fb-1 data sample collected with the Belle detector at the KEKB e+e- collider. Clear peaks due to the a0(980) and a2(1320) are visible. The differential cross sections are fitted in the energy region 0.9GeV<W<1.46GeV to obtain the parameters of the a0(980). Its mass, width and ΓγγB(ηπ0) are measured to be 982.3-0.7-4.7+0.6+3. 1MeV/c2, 75.6±1.6-10.0+17.4MeV and 128-2-43+3+502eV, respectively. The energy and angular dependences above 3.1 GeV are compared with those measured in the π0π0 channel. The integrated cross section over θ*|<0. 8 has a W-n dependence with n=10.5±1.2±0.5, which is slightly larger than that for π0π0. The differential cross sections show a sin-4θ* dependence similar to γγ→π0π0. The measured cross section ratio, σ(ηπ0)/σ(π0π0)=0. 48±0.05±0.04, is consistent with a QCD-based prediction. © 2009 The American Physical Society.Photon-Photon CollisionsBelleEnergiesGammatext::journal::journal article::research article