1305.5887 (Belle Collaboration et al.)

Measurement of exclusive $Υ(1S)$ and $Υ(2S)$ decays into
Vector-Pseudoscalar final states    [PDF]

Belle Collaboration, C. P. Shen, C. Z. Yuan, I. Adachi, H. Aihara, D. M. Asner, V. Aulchenko, A. M. Bakich, A. Bala, B. Bhuyan, M. Bischofberger, A. Bozek, M. Bračko, T. E. Browder, V. Chekelian, A. Chen, P. Chen, B. G. Cheon, K. Chilikin, I. -S. Cho, K. Cho, V. Chobanova, Y. Choi, D. Cinabro, J. Dalseno, M. Danilov, J. Dingfelder, Z. Doležal, Z. Drásal, A. Drutskoy, D. Dutta, K. Dutta, S. Eidelman, D. Epifanov, H. Farhat, J. E. Fast, T. Ferber, A. Frey, V. Gaur, N. Gabyshev, S. Ganguly, R. Gillard, Y. M. Goh, B. Golob, J. Haba, T. Hara, K. Hayasaka, H. Hayashii, Y. Hoshi, W. -S. Hou, H. J. Hyun, T. Iijima, A. Ishikawa, R. Itoh, Y. Iwasaki, T. Julius, D. H. Kah, J. H. Kang, E. Kato, T. Kawasaki, C. Kiesling, D. Y. Kim, H. J. Kim, J. B. Kim, J. H. Kim, K. T. Kim, Y. J. Kim, K. Kinoshita, J. Klucar, B. R. Ko, P. Kodyš, S. Korpar, P. Križan, P. Krokovny, T. Kumita, A. Kuzmin, Y. -J. Kwon, S. -H. Lee, R. Leitner, J. Li, Y. Li, J. Libby, C. Liu, Y. Liu, Z. Q. Liu, D. Liventsev, P. Lukin, D. Matvienko, K. Miyabayashi, H. Miyata, G. B. Mohanty, A. Moll, T. Mori, N. Muramatsu, R. Mussa, Y. Nagasaka, E. Nakano, M. Nakao, Z. Natkaniec, M. Nayak, E. Nedelkovska, C. Ng, N. K. Nisar, S. Nishida, O. Nitoh, S. Ogawa, S. Okuno, S. L. Olsen, W. Ostrowicz, P. Pakhlov, C. W. Park, H. Park, H. K. Park, T. K. Pedlar, T. Peng, R. Pestotnik, M. Petrič, L. E. Piilonen, M. Ritter, M. Röhrken, A. Rostomyan, S. Ryu, H. Sahoo, T. Saito, Y. Sakai, S. Sandilya, L. Santelj, T. Sanuki, Y. Sato, V. Savinov, O. Schneider, G. Schnell, C. Schwanda, K. Senyo, O. Seon, M. Shapkin, V. Shebalin, T. -A. Shibata, J. -G. Shiu, B. Shwartz, A. Sibidanov, F. Simon, P. Smerkol, Y. -S. Sohn, A. Sokolov, E. Solovieva, S. Stanič, M. Starič, M. Steder, M. Sumihama, T. Sumiyoshi, U. Tamponi, K. Tanida, G. Tatishvili, Y. Teramoto, T. Tsuboyama, M. Uchida, S. Uehara, Y. Unno, S. Uno, P. Urquijo, C. Van Hulse, P. Vanhoefer, G. Varner, V. Vorobyev, M. N. Wagner, C. H. Wang, P. Wang, X. L. Wang, M. Watanabe, Y. Watanabe, E. Won, H. Yamamoto, J. Yamaoka, Y. Yamashita, S. Yashchenko, Y. Yook, Y. Yusa, C. C. Zhang, Z. P. Zhang, A. Zupanc

Using samples of 102 million $\Upsilon(1S)$ and 158 million $\Upsilon(2S)$ events collected with the Belle detector, we study exclusive hadronic decays of these two bottomonium resonances to $\ks K^+ \pi^-$ and charge-conjugate (c.c.) states, $\pi^+ \pi^- \pi^0 \pi^0$, and $\pi^+ \pi^- \pi^0$, and to the two-body Vector-Pseudoscalar ($K^{\ast}(892)^0\bar{K}^0+ {\rm c.c.}$, $K^{\ast}(892)^-K^+ + {\rm c.c.}$, $\omega\pi^0$, and $\rho\pi$) final states. For the first time, signals are observed in the modes $\Upsilon(1S) \to \ks K^+ \pi^- + {\rm c.c.}$, $\pi^+ \pi^- \pi^0 \pi^0$, and $\Upsilon(2S) \to \pi^+ \pi^- \pi^0 \pi^0$, and evidence is found for the modes $\Upsilon(1S)\to \pi^+ \pi^- \pi^0$, $K^{\ast}(892)^0 \bar{K}^0+ {\rm c.c.}$, and $\Upsilon(2S) \to \ks K^+ \pi^- + {\rm c.c.}$ Branching fractions are measured for all the processes, while 90% confidence level upper limits on the branching fractions are also set for the modes with a statistical significance of less than $3\sigma$. The ratios of the branching fractions of $\Upsilon(2S)$ and $\Upsilon(1S)$ decays into the same final state are used to test a perturbative QCD prediction for OZI-suppressed bottomonium decays.

View original: http://arxiv.org/abs/1305.5887