Measurement of the e+e- -->pi+pi- J/psi cross section via initial-state radiation at Belle.
The cross section for e(+)e(-)-->pi(+)pi(-)J/psi between 3.8 and 5.5 GeV/c(2) is measured using a 548 fb(-1) data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c(2), corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c(2). A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement.
Yuan
C Z
CZ
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing.
Shen
C P
CP
Wang
P
P
McOnie
S
S
Adachi
I
I
Aihara
H
H
Aulchenko
V
V
Aushev
T
T
Bahinipati
S
S
Balagura
V
V
Barberio
E
E
Bedny
I
I
Bitenc
U
U
Bondar
A
A
Bozek
A
A
Bracko
M
M
Brodzicka
J
J
Browder
T E
TE
Chang
M-C
MC
Chang
P
P
Chen
A
A
Chen
K-F
KF
Chen
W T
WT
Cheon
B G
BG
Chistov
R
R
Cho
I-S
IS
Choi
Y
Y
Dalseno
J
J
Danilov
M
M
Dash
M
M
Eidelman
S
S
Fratina
S
S
Gabyshev
N
N
Golob
B
B
Ha
H
H
Haba
J
J
Hayasaka
K
K
Hayashii
H
H
Hazumi
M
M
Heffernan
D
D
Hokuue
T
T
Hoshi
Y
Y
Hou
W-S
WS
Hsiung
Y B
YB
Hyun
H J
HJ
Iijima
T
T
Ikado
K
K
Inami
K
K
Ishikawa
A
A
Itoh
R
R
Iwasaki
Y
Y
Kah
D H
DH
Kaji
H
H
Kang
J H
JH
Katayama
N
N
Kawai
H
H
Kawasaki
T
T
Kichimi
H
H
Kim
Y J
YJ
Kinoshita
K
K
Korpar
S
S
Krizan
P
P
Krokovny
P
P
Kumar
R
R
Kuo
C C
CC
Kuzmin
A
A
Kwon
Y-J
YJ
Lee
S E
SE
Lesiak
T
T
Lin
S-W
SW
Liu
Y
Y
Liventsev
D
D
Mandl
F
F
Marlow
D
D
Matyja
A
A
Medvedeva
T
T
Mitaroff
W
W
Miyabayashi
K
K
Miyake
H
H
Miyata
H
H
Miyazaki
Y
Y
Mizuk
R
R
Mori
T
T
Nagasaka
Y
Y
Nakao
M
M
Natkaniec
Z
Z
Nishida
S
S
Nitoh
O
O
Ogawa
S
S
Ohshima
T
T
Okuno
S
S
Olsen
S L
SL
Ozaki
H
H
Pakhlov
P
P
Pakhlova
G
G
Palka
H
H
Park
H
H
Park
K S
KS
Peak
L S
LS
Piilonen
L E
LE
Sakai
Y
Y
Schneider
O
O
Schümann
J
J
Seidl
R
R
Senyo
K
K
Sevior
M E
ME
Shapkin
M
M
Shibuya
H
H
Shiu
J-G
JG
Shwartz
B
B
Singh
J B
JB
Sokolov
A
A
Somov
A
A
Staric
M
M
Sumiyoshi
T
T
Takasaki
F
F
Tanaka
M
M
Taylor
G N
GN
Teramoto
Y
Y
Tikhomirov
I
I
Uehara
S
S
Unno
Y
Y
Uno
S
S
Usov
Y
Y
Varner
G
G
Varvell
K E
KE
Vervink
K
K
Villa
S
S
Vinokurova
A
A
Wang
C C
CC
Wang
C H
CH
Wang
X L
XL
Watanabe
Y
Y
Won
E
E
Yabsley
B D
BD
Yamaguchi
A
A
Yamashita
Y
Y
Zhang
C C
CC
Zhang
Z P
ZP
Zhilich
V
V
Zhulanov
V
V
Zupanc
A
A