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ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2010, vol. 82, p. -

Observation of an enhancement in e+e-→Υ(1S) πn+n-→Υ(2S)n+n- and (3S)n+n- production near s = 10.89 GeV

Chen K. F., Hou W. S., Adachi I., Aihara H., Aushev T., Bakich A. M., Balagura V., Bay A., Belous K., Bhardwaj V., Bischofberger M., Bondar A., Bozek A., Bračko M., Brodzicka J., Browder T. E., Chang M. C., Chang P., Chao Y., Chen A., Chen P., Cheon B. G., Chiang C. C., Chistov R., Cho I. S., Choi Y., Dalseno J., Drutskoy A., Eidelman S., Epifanov D., Gabyshev N., Goldenzweig P., Ha H., Han B. Y., Hayasaka K., Hayashii H., Hazumi M., Hoshi Y., Hsiung Y. B., Hyun H. J., Iijima T., Inami K., Itoh R., Iwabuchi M., Iwasaki Y., Julius T., Kah D. H., Kang J. H., Katayama N., Kiesling C., Kim H. O., Kim Y. I., Kim Y. J., Kinoshita K., Ko B. R., Korpar S., Kriaan P., Krokovny P., Kwon Y. J., Kyeong S. H., Lange J. S., Lee S. H., Li J., Liu C., Liu Y., Liventsev D., Louvot R., MacNaughton J., Matyja A., McOnie S., Miyabayashi K., Miyata H., Miyazaki Y., Mizuk R., Nagasaka Y., Nakano E., Nakao M., Nishida S., Nishimura K., Nitoh O., Nozaki T., Ogawa S., Ohshima T., Okuno S., Pakhlova G., Park H., Park H. K., Pestotnik R., Petrič M., Piilonen L. E., Ryu S.

We measure the production cross sections for e+e -→Υ(1S)π+π-, Υ(2S)π+π-, and Υ(3S) π+π- as a function of √s between 10.83 GeV and 11.02 GeV. The data consist of 8.1fb-1 collected with the Belle detector at the KEKB e+e- collider. We observe enhanced production in all three final states that does not agree well with the conventional Υ(10860) line shape. A fit using a Breit-Wigner resonance shape yields a peak mass of [10888.4-2.6+2.7(stat)±1.2(syst)]MeV/c2 and a width of [30.7-7.0+8.3(stat)±3.1(syst)]MeV/c2. © 2010 The American Physical Society.