Observation of anomalous upsilon(1S)pi+pi(-) and upsilon(2S)pi+pi(-) production near the upsilon(5S) resonance.
We report the first observation of e;{+}e;{-}-->Upsilon(1S)pi;{+}pi;{-}, Upsilon(2S)pi;{+}pi;{-}, and first evidence for e;{+}e;{-}-->Upsilon(3S)pi;{+}pi;{-}, Upsilon(1S)K+K-, near the peak of the Upsilon(5S) resonance at sqrt[s] approximately 10.87 GeV. The results are based on a data sample of 21.7 fb;{-1} collected with the Belle detector at the KEKB e;{+}e;{-} collider. Attributing the signals to the Upsilon(5S) resonance, the partial widths Gamma(Upsilon(5S)-->Upsilon(1S)pi;{+}pi;{-})=0.59+/-0.04(stat)+/-0.09(syst) MeV and Gamma(Upsilon(5S)-->Upsilon(2S)pi;{+}pi;{-})=0.85+/-0.07(stat)+/-0.16(syst) MeV are obtained from the observed cross sections. These values exceed by more than 2 orders of magnitude the previously measured partial widths for dipion transitions between lower Upsilon resonances.
Chen
K-F
KF
Department of Physics, National Taiwan University, Taipei.
Hou
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Shapkin
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Gabyshev
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Golob
B
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Hayasaka
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Hayashii
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Hazumi
M
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Heffernan
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Hoshi
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Hsiung
Y B
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Iijima
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A
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Ishino
H
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Miyake
H
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Mizuk
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Nakao
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Natkaniec
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Nishida
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Nitoh
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Ogawa
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Ohshima
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Okuno
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Olsen
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Ostrowicz
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Ozaki
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Pakhlov
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Palka
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Park
C W
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Park
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K S
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Pestotnik
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L E
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Sakai
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Schneider
O
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Schwanda
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A J
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Senyo
K
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Sevior
M E
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J-G
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Shwartz
B
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Somov
A
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Stanic
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Staric
M
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Sumiyoshi
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Takasaki
F
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Tamai
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Taylor
G N
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Teramoto
Y
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Trabelsi
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Uehara
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Uglov
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Unno
Y
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Urquijo
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M-Z
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X L
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Watanabe
Y
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B D
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Yamauchi
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Yusa
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Zhang
C C
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Zupanc
A
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