Study of η and dipion transitions in Υ ( 4S ) decays to lower bottomonia

• Published in: Physical review. D 2017-09, Vol.96 (5)
• Main Authors: Guido, E., Mussa, R., Aihara, H., Al Said, S., Asner, D. M., Badhrees, I., Bakich, A. M., Bansal, V., Behera, P., Bhardwaj, V., Biswal, J., Bondar, A., Bozek, A., Bračko, M., Browder, T. E., Cheon, B. G., Chilikin, K., Cho, K., Choi, S. -K., Dash, N., Di Carlo, S., Farhat, H., Fulsom, B. G., Gaur, V., Gabyshev, N., Garmash, A., Haba, J., Hara, T., Hayasaka, K., Hayashii, H., Hou, W. -S., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, Y., Jaegle, I., Jeon, H. B., Joo, K. K., Kang, K. H., Karyan, G., Kim, J. B., Kim, K. T., Kim, S. H., Kim, Y. J., Kodyš, P., Korpar, S., Kotchetkov, D., Kuzmin, A., Kwon, Y. -J., Lange, J. S., Lewis, P., Libby, J., Liventsev, D., Matsuda, T., Matvienko, D., Miyabayashi, K., Miyata, H., Mizuk, R., Moon, H. K., Mori, T., Nanut, T., Nath, K. J., Nisar, N. K., Nishida, S., Ogawa, S., Pal, B., Pardi, S., Park, C. -S., Park, H., Pedlar, T. K., Piilonen, L. E., Pulvermacher, C., Ritter, M., Rostomyan, A., Sakai, Y., Sanuki, T., Savinov, V., Schneider, O., Seino, Y., Sevior, M. E., Shen, C. P., Shibata, T. -A., Shwartz, B., Sokolov, A., Sumisawa, K., Takizawa, M., Tanida, K., Tenchini, F., Trabelsi, K., Vorobyev, V., Vossen, A., Wang, C. H., Wang, P., Wang, X. L., Watanuki, S., Ye, H., Zhilich, V., Zhulanov, V., Zupanc, A.
• Format: Article
• Language: English
• Subjects: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 2470-0010

Here, we study hadronic transitions between bottomonium states using 496fb-1 data collected at the Υ ( 4S ) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. We measure B ( Υ ( 4S ) → π+π- Υ ( 1S ) ) = ( 8.2±0.5 ( stat ) ±0.4 ( syst ) ) ×10-5 , B ( Υ ( 4S ) → π+π- Υ ( 2S ) ) = ( 7.9±1.0 ( stat ) ± 0.4 ( syst ) ) ×10-5 , and B ( Υ ( 4S ) → η Υ ( 1S ) ) = ( 1.70±0.23 ( stat ) ±0.08 ( syst ) ) ×10-4 . We measure the ratio of branching fractions R = B ( Υ ( 4S ) → η Υ ( 1S ) ) / B ( Υ ( 4S ) → π+π- Υ ( 1S ) ) =2.07±0.30 ( stat ) ± 0.11 ( syst ) . We search for the decay Υ ( 1D31,2 ) → η Υ ( 1S ) , but do not find significant evidence for such a transition. We also measure the initial-state radiation production cross sections of the Υ ( 2S,3S ) resonances and we find values compatible with the expected ones. Finally, the analysis of the Υ ( 4S ) → π+π- Υ ( 1S ) events reflects indications for a resonant contribution due to the f0 ( 980 ) meson.