Study of J/psi-->pp[over],LambdaLambda[over] and observation of eta(c)-->LambdaLambda[over] at Belle.
We study the baryonic charmonium decays of B mesons B+-->etacK+ and B+-->J/psiK+, where the etac and J/psi subsequently decay into a pp[over] or LambdaLambda[over] pair. We measure the J/psi-->pp[over] and LambdaLambda[over] anisotropy parameters alphaB=-0.60+/-0.13+/-0.14 (pp[over]), -0.44+/-0.51+/-0.31 (LambdaLambda[over ]) and compare to results from e;{+}e;{-}-->J/psi formation experiments. We also report the first observation of etac-->LambdaLambda[over]. The measured branching fraction is B(etac-->LambdaLambda[over ])=(0.87(+0.24)/(-0.21)(stat)(+0.09/-0.14) (syst)+/-0.27(PDG))x10-3. This study is based on a 357 fb-1 data sample recorded on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.
Wu
C-H
CH
Department of Physics, National Taiwan University, Taipei, Taiwan.
Wang
M-Z
MZ
Abe
K
K
Adachi
I
I
Aihara
H
H
Aulchenko
V
V
Aushev
T
T
Bahinipati
S
S
Bakich
A M
AM
Balagura
V
V
Bay
A
A
Belous
K
K
Bitenc
U
U
Bizjak
I
I
Blyth
S
S
Bondar
A
A
Bozek
A
A
Browder
T E
TE
Chao
Y
Y
Chen
A
A
Chen
W T
WT
Cheon
B G
BG
Choi
Y
Y
Choi
Y K
YK
Chuvikov
A
A
Cole
S
S
Dalseno
J
J
Danilov
M
M
Dash
M
M
Eidelman
S
S
Gabyshev
N
N
Gershon
T
T
Go
A
A
Gokhroo
G
G
Gorisek
A
A
Ha
H
H
Haba
J
J
Hayasaka
K
K
Hayashii
H
H
Hazumi
M
M
Heffernan
D
D
Hokuue
T
T
Hou
S
S
Hou
W-S
WS
Hsiung
Y B
YB
Iijima
T
T
Inami
K
K
Ishikawa
A
A
Itoh
R
R
Iwasaki
M
M
Iwasaki
Y
Y
Kang
J H
JH
Kataoka
S U
SU
Katayama
N
N
Kawai
H
H
Kawasaki
T
T
Khan
H R
HR
Kichimi
H
H
Kim
H J
HJ
Kim
H O
HO
Kim
Y J
YJ
Krizan
P
P
Krokovny
P
P
Kulasiri
R
R
Kumar
R
R
Kuo
C C
CC
Kuzmin
A
A
Kwon
Y-J
YJ
Leder
G
G
Lee
J
J
Lee
Y-J
YJ
Lesiak
T
T
Lin
S-W
SW
Liventsev
D
D
Majumder
G
G
Mandl
F
F
Matsumoto
T
T
Matyja
A
A
McOnie
S
S
Mitaroff
W
W
Miyabayashi
K
K
Miyake
H
H
Miyata
H
H
Miyazaki
Y
Y
Mizuk
R
R
Mori
T
T
Nakano
E
E
Nakao
M
M
Natkaniec
Z
Z
Nishida
S
S
Nitoh
O
O
Ogawa
S
S
Ohshima
T
T
Okabe
T
T
Okuno
S
S
Olsen
S L
SL
Onuki
Y
Y
Ozaki
H
H
Pakhlov
P
P
Palka
H
H
Park
H
H
Park
K S
KS
Pestotnik
R
R
Piilonen
L E
LE
Sakai
Y
Y
Schietinger
T
T
Schneider
O
O
Schwartz
A J
AJ
Seidl
R
R
Sevior
M E
ME
Shapkin
M
M
Shibuya
H
H
Sidorov
V
V
Sokolov
A
A
Somov
A
A
Soni
N
N
Stanic
S
S
Staric
M
M
Stoeck
H
H
Sumiyoshi
T
T
Takasaki
F
F
Tanaka
M
M
Taylor
G N
GN
Teramoto
Y
Y
Tian
X C
XC
Tsuboyama
T
T
Tsukamoto
T
T
Uehara
S
S
Uglov
T
T
Ueno
K
K
Uno
S
S
Urquijo
P
P
Usov
Y
Y
Varner
G
G
Wang
C C
CC
Wang
C H
CH
Watanabe
Y
Y
Won
E
E
Yabsley
B D
BD
Yamaguchi
A
A
Yamashita
Y
Y
Zhang
L M
LM
Zhang
Z P
ZP