High-statistics study of neutral-pion pair production in two-photon collisions
Year: 2009
Type: article
Abstract: The differential cross sections for the process $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ have been measured in the kinematic range $0.6\text{ }\text{ }\mathrm{GeV}<W<4.1\text{ }\text{ }\mathrm{GeV}$, $|\mathrm{cos}{\ensuremath{\theta}}^{*}|<0.8$ in energy and pion scattering angle, respectively, in the $\ensuremath{\gamma}\ensuremath{\gamma}$ center-of-mass system. The results are based on a $223\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected with the Belle detector at the KEKB ${e}^{+}{e}^{\ensuremath{-}}$ collider. The differential cross sections are fitted in the energy region $1.7\text{ }\text{ }\mathrm{GeV}<W<2.5\text{ }\text{ }\mathrm{GeV}$ to confirm the two-photon production of two pions in the $G$ wave. In the higher-energy region, we observe production of the ${\ensuremath{\chi}}_{c0}$ charmonium state and obtain the product of its two-photon decay width and branching fraction to ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$. 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 ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ channel, and in addition we find that the cross section ratio, $\ensuremath{\sigma}({\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})/\ensuremath{\sigma}({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$, is $0.32\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.05$ on average in the 3.1--4.1 GeV region.
Authors: S. Uehara, Y. Watanabe, H. Nakazawa, H. Aihara, K. Arinstein, V. Aulchenko, A. M. Bakich, E. Barberio, K. Belous, V. Bhardwaj, A. Bondar, A. Bozek, M. Bračko, T. E. Browder, A. Chen, B. G. Cheon, R. Chistov, I.-S. Cho, S.-K. Choi, Y. Choi, M. Dash, S. Eidelman, D. Epifanov, N. Gabyshev, P. Goldenzweig, H. Ha, J. Haba, B.-Y. Han, K. Hayasaka, H. Hayashii, M. Hazumi, Y. Hoshi, W.-S. Hou, H. J. Hyun, K. Inami, A. Ishikawa, Y. Iwasaki, N. J. Joshi, D. H. Kah, N. Katayama, T. Kawasaki, H. Kichimi, H. O. Kim, Y. I. Kim, Y. J. Kim, S. Korpar, P. Križan, P. Krokovny, A. Kuzmin, Y.-J. Kwon, M. J. Lee, T. Lesiak, Y. Liu, D. Liventsev, R. Louvot, S. McOnie, H. Miyata, R. Mizuk, Y. Nagasaka, M. Nakao, S. Nishida, K. Nishimura, O. Nitoh, S. Ogawa, T. Ohshima, S. Okuno, P. Pakhlov, G. Pakhlova, C. W. Park, H. Park, H. K. Park, R. Pestotnik, L. E. Piilonen, A. Poluektov, H. Sahoo, Y. Sakai, O. Schneider, K. Senyo, M. Shapkin, J.-G. Shiu, B. Shwartz, M. Starič, T. Sumiyoshi, M. Tanaka, Y. Teramoto, I. Tikhomirov, T. Uglov, Y. Unno, S. Uno, Y. Usov, G. Varner, K. Vervink, A. Vinokurova, C. H. Wang, P. Wang, B. D. Yabsley, Y. Yamashita, C. C. Zhang, Z. P. Zhang, V. Zhilich, V. Zhulanov, T. Zivko, A. Zupanc, O. Zyukova
Institutions: High Energy Accelerator Research Organization, Kanagawa University, National Central University, The University of Tokyo, Novosibirsk State University, Budker Institute of Nuclear Physics, The University of Sydney, The University of Melbourne, Institute for High Energy Physics, Panjab University, Institute of Nuclear Physics, Polish Academy of Sciences, Jožef Stefan Institute, University of Maribor, University of Hawaiʻi at Mānoa, University of Hawaii System, Hanyang University, Institute for Theoretical and Experimental Physics, Yonsei University, Gyeongsang National University, Sungkyunkwan University, Virginia Tech, University of Cincinnati, Korea University, Nagoya University, Nara Women's University, Tohoku Gakuin University, National Taiwan University, Kyungpook National University, Saga University, Tata Institute of Fundamental Research, Niigata University, The Graduate University for Advanced Studies, SOKENDAI, University of Ljubljana, Seoul National University, Cracow University of Technology, École Polytechnique Fédérale de Lausanne, Hiroshima Institute of Technology, Tokyo University of Agriculture and Technology, Toho University, Tokyo Metropolitan University, Osaka City University, National United University, Chinese Academy of Sciences, Institute of High Energy Physics, Nippon Dental University, University of Science and Technology of China
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: U.S. Department of Energy, Ministry of Education, Culture, Sports, Science and Technology, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, National Natural Science Foundation of China, National Science Council, Ministry of Education and Science of the Russian Federation, Korea Science and Engineering Foundation, Javna Agencija za Raziskovalno Dejavnost RS, National Institute of Informatics, Japan Society for the Promotion of Science
OpenAlex ID: W2148489446