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arXiv · 1604.02525

First observation of $\gamma \gamma \to p \bar{p} K^+ K^-$ and search for exotic baryons in $pK$ systems

Belle Collaboration·C. P. Shen·C. Z. Yuan·I. Adachi·H. Aihara·D. M. Asner·V. Aulchenko·T. Aushev·R. Ayad·V. Babu·I. Badhrees·A. M. Bakich·E. Barberio·P. Behera·V. Bhardwaj·B. Bhuyan·J. Biswal·A. Bobrov·G. Bonvicini·A. Bozek·M. Bračko·T. E. Browder·D. Červenkov·P. Chang·V. Chekelian·A. Chen·B. G. Cheon·K. Chilikin·R. Chistov·K. Cho·V. Chobanova·S. -K. Choi·Y. Choi·D. Cinabro·J. Dalseno·M. Danilov·N. Dash·Z. Doležal·Z. Drásal·D. Dutta·S. Eidelman·W. X. Fang·J. E. Fast·T. Ferber·B. G. Fulsom·V. Gaur·N. Gabyshev·A. Garmash·R. Gillard·R. Glattauer·P. Goldenzweig·O. Grzymkowska·J. Haba·K. Hayasaka·H. Hayashii·W. -S. Hou·T. Iijima·K. Inami·G. Inguglia·A. Ishikawa·R. Itoh·Y. Iwasaki·I. Jaegle·H. B. Jeon·K. K. Joo·T. Julius·K. H. Kang·E. Kato·C. Kiesling·D. Y. Kim·J. B. Kim·K. T. Kim·S. H. Kim·Y. J. Kim·P. Kodyš·S. Korpar·D. Kotchetkov·P. Križan·P. Krokovny·A. Kuzmin·Y. -J. Kwon·J. S. Lange·C. H. Li·H. Li·L. Li·Y. Li·L. Li Gioi·J. Libby·D. Liventsev·M. Lubej·T. Luo·M. Masuda·T. Matsuda·D. Matvienko·K. Miyabayashi·H. Miyata·R. Mizuk·G. B. Mohanty·S. Mohanty·A. Moll
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Abstract

The process $\gamma \gamma \to p \bar{p} K^+ K^-$ and its intermediate processes are measured for the first time using a 980~fb$^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The production of $p \bar{p} K^+ K^-$ and a $\Lambda(1520)^0~(\bar{\Lambda}(1520)^0)$ signal in the $pK^-$~($\bar{p} K^+$) invariant mass spectrum are clearly observed. However, no evidence for an exotic baryon near 1540~MeV/$c^2$, denoted as $\Theta(1540)^0$~($\bar{\Theta}~(1540)^0$) or $\Theta(1540)^{++}$~($\Theta(1540)^{--}$), is seen in the $p K^-$~($\bar{p}K^+$) or $pK^+$~($\bar{p} K^-$) invariant mass spectra. Cross sections for $\gamma \gamma \to p \bar{p} K^+ K^-$, $\Lambda(1520)^0 \bar{p} K^+ +c.c.$ and the products $\sigma(\gamma \gamma \to \Theta(1540)^0 \bar{p} K^+ +c.c.)\BR(\Theta(1540)^0 \to p K^{-})$ and $\sigma(\gamma \gamma \to \Theta(1540)^{++} \bar{p} K^- +c.c.)\BR(\Theta(1540)^{++}\to p K^{+})$ are measured. We also determine upper limits on the products of the $\chi_{c0}$ and $\chi_{c2}$ two-photon decay widths and their branching fractions to $p \bar{p} K^+ K^-$ at the 90\% credibility level.

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Belle Collaboration, C. P. Shen, C. Z. Yuan, I. Adachi, H. Aihara, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Bakich, E. Barberio, P. Behera, V. Bhardwaj, B. Bhuyan, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, D. Červenkov, P. Chang, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, R. Chistov, K. Cho, V. Chobanova, S. -K. Choi, Y. Choi, D. Cinabro, J. Dalseno, M. Danilov, N. Dash, Z. Doležal, Z. Drásal, D. Dutta, S. Eidelman, W. X. Fang, J. E. Fast, T. Ferber, B. G. Fulsom, V. Gaur, N. Gabyshev, A. Garmash, R. Gillard, R. Glattauer, P. Goldenzweig, O. Grzymkowska, J. Haba, K. Hayasaka, H. Hayashii, W. -S. Hou, T. Iijima, K. Inami, G. Inguglia, A. Ishikawa, R. Itoh, Y. Iwasaki, I. Jaegle, H. B. Jeon, K. K. Joo, T. Julius, K. H. Kang, E. Kato, C. Kiesling, D. Y. Kim, J. B. Kim, K. T. Kim, S. H. Kim, Y. J. Kim, P. Kodyš, S. Korpar, D. Kotchetkov, P. Križan, P. Krokovny, A. Kuzmin, Y. -J. Kwon, J. S. Lange, C. H. Li, H. Li, L. Li, Y. Li, L. Li Gioi, J. Libby, D. Liventsev, M. Lubej, T. Luo, M. Masuda, T. Matsuda, D. Matvienko, K. Miyabayashi, H. Miyata, R. Mizuk, G. B. Mohanty, S. Mohanty, A. Moll. 2016-04-09. First observation of $\gamma \gamma \to p \bar{p} K^+ K^-$ and search for exotic baryons in $pK$ systems. https://doi.org/10.1103/physrevd.93.112017

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