Belle CollaborationUehara, S.Watanabe, Y.Nakazawa, H.Aihara, H.Arinstein, K.Aulchenko, V.Bakich, A.Barberio, E.Belous, K.Bhardwaj, V.Bondar, A.Bozek, A.Bračko, M.Browder, T.Chen, A.Cheon, B.Chistov, R.Cho, I.-S.Choi, S.-K.Choi, Y.Dash, M.Eidelman, S.Epifanov, D.Gabyshev, N.Goldenzweig, P.Ha, H.Haba, J.Han, B.-Y.Hayasaka, K.Hayashii, H.Hazumi, M.Hoshi, Y.Hou, W.-S.Hyun, H.Inami, K.Ishikawa, A.Iwasaki, Y.Joshi, N.Kah, D.Katayama, N.Kawasaki, T.Kichimi, H.Kim, H.Kim, Y.Kim, Y.Korpar, S.Križan, P.Krokovny, P.Kuzmin, A.Kwon, Y.-J.Lee, M.Lesiak, T.Liu, Y.Liventsev, D.Louvot, R.Mconie, S.Miyata, H.Mizuk, R.Nagasaka, Y.Nakao, M.Nishida, S.Nishimura, K.Nitoh, O.Ogawa, S.Ohshima, T.Okuno, S.Pakhlov, P.Pakhlova, G.Park, C.Park, H.Park, H.Pestotnik, R.Piilonen, L.Poluektov, A.Sahoo, H.Sakai, Y.Schneider, O.Senyo, K.Shapkin, M.Shiu, J.-G.Shwartz, B.Starič, M.Sumiyoshi, T.Tanaka, M.Teramoto, Y.Tikhomirov, I.Uglov, T.Unno, Y.Uno, S.Usov, Y.Varner, G.Vervink, K.Vinokurova, A.Wang, C.Wang, P.Yabsley, B.Yamashita, Y.Zhang, C.Zhang, Z.Zhilich, V.Zhulanov, V.Zivko, T.Zupanc, A.Zyukova, O.2010-11-052010-11-052010-11-05200910.1103/PhysRevD.79.052009https://infoscience.epfl.ch/handle/20.500.14299/56961WOS:000264762400016The differential cross sections for the process gamma gamma -> pi(0)pi(0) have been measured in the kinematic range 0.6 GeV < W < 4.1 GeV, vertical bar cos theta* vertical bar < 0.8 in energy and pion scattering angle, respectively, in the gamma gamma center-of-mass system. The results are based on a 223 fb(-1) data sample collected with the Belle detector at the KEKB e(+)e(-) collider. The differential cross sections are fitted in the energy region 1.7 GeV < W < 2.5 GeV to confirm the two-photon production of two pions in the G wave. In the higher-energy region, we observe production of the chi(c0) charmonium state and obtain the product of its two-photon decay width and branching fraction to pi(0)pi(0). We also compare the observed angular dependence and ratios of cross sections for neutral-pion and charged-pion pair production to QCD models. The energy and angular dependence above 3.1 GeV are compatible with those measured in the pi(+)pi(-) channel, and in addition we find that the cross section ratio, sigma(pi(0)pi(0))/sigma(pi(+)pi(-)), is 0.32 +/- 0.03 +/- 0.05 on average in the 3.1-4.1 GeV region.BelleEnergiesGammaKktext::journal::journal article::research article