Measurement of the CP asymmetry in B-->Xs gamma.
Direct CP violation in the b-->sgamma process is a sensitive probe of physics beyond the standard model. We report a measurement of the CP asymmetry in B-->X(s)gamma, where the hadronic recoil system X(s) is reconstructed using a pseudoreconstruction technique. In this approach there is negligible contamination from b-->dgamma decays, which are expected to have a much larger CP asymmetry. We find A(CP)=0.002+/-0.050(stat)+/-0.030(syst) for B-->X(s)gamma events having recoil mass smaller than 2.1 GeV/c(2). The analysis is based on a data sample of 140 fb(-1) recorded at the upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring.
Nishida
S
S
High Energy Accelerator Research Organization (KEK), Tsukuba.
Abe
K
K
Abe
K
K
Abe
T
T
Aihara
H
H
Asano
Y
Y
Aushev
T
T
Bahinipati
S
S
Bakich
A M
AM
Ban
Y
Y
Banas
E
E
Bay
A
A
Bitenc
U
U
Bizjak
I
I
Blyth
S
S
Bondar
A
A
Bozek
A
A
Bracko
M
M
Brodzicka
J
J
Browder
T E
TE
Chang
M-C
MC
Chang
P
P
Chen
K-F
KF
Cheon
B G
BG
Chistov
R
R
Choi
S-K
SK
Choi
Y
Y
Chuvikov
A
A
Cole
S
S
Danilov
M
M
Dash
M
M
Dong
L Y
LY
Dragic
J
J
Eidelman
S
S
Eiges
V
V
Enari
Y
Y
Epifanov
D
D
Fang
F
F
Fratina
S
S
Garmash
A
A
Gershon
T
T
Gokhroo
G
G
Golob
B
B
Haba
J
J
Hara
T
T
Hastings
N C
NC
Hayashii
H
H
Hazumi
M
M
Higuchi
T
T
Hinz
L
L
Hoshi
Y
Y
Hou
W-S
WS
Hsiung
Y B
YB
Iijima
T
T
Inami
K
K
Ishikawa
A
A
Ishino
H
H
Itoh
R
R
Iwasaki
M
M
Iwasaki
Y
Y
Kang
J H
JH
Kang
J S
JS
Kapusta
P
P
Kataoka
S U
SU
Katayama
N
N
Kawasaki
T
T
Kichimi
H
H
Kim
H J
HJ
Kim
S K
SK
Kim
T H
TH
Koppenburg
P
P
Korpar
S
S
Krizan
P
P
Krokovny
P
P
Kuzmin
A
A
Kwon
Y-J
YJ
Lange
J S
JS
Leder
G
G
Lee
S E
SE
Lee
S H
SH
Li
J
J
Lin
S-W
SW
MacNaughton
J
J
Majumder
G
G
Mandl
F
F
Matsumoto
T
T
Matyja
A
A
Mitaroff
W
W
Miyake
H
H
Mizuk
R
R
Mohapatra
D
D
Moloney
G R
GR
Murakami
A
A
Nagamine
T
T
Nagasaka
Y
Y
Nakano
E
E
Nakao
M
M
Nakazawa
H
H
Natkaniec
Z
Z
Nitoh
O
O
Nozaki
T
T
Ogawa
S
S
Ohshima
T
T
Okabe
T
T
Okuno
S
S
Olsen
S L
SL
Ozaki
H
H
Pakhlov
P
P
Palka
H
H
Park
C W
CW
Park
H
H
Peters
M
M
Piilonen
L E
LE
Ronga
F J
FJ
Rozanska
M
M
Sakai
Y
Y
Schneider
O
O
Schümann
J
J
Schwanda
C
C
Semenov
S
S
Seuster
R
R
Sevior
M E
ME
Shibuya
H
H
Shwartz
B
B
Somov
A
A
Soni
N
N
Stamen
R
R
Stanic
S
S
Staric
M
M
Sugiyama
A
A
Sumiyoshi
T
T
Suzuki
S
S
Tajima
O
O
Takasaki
F
F
Tamai
K
K
Tanaka
M
M
Teramoto
Y
Y
Tomura
T
T
Trabelsi
K
K
Tsuboyama
T
T
Tsukamoto
T
T
Uehara
S
S
Uglov
T
T
Ueno
K
K
Unno
Y
Y
Uno
S
S
Ushiroda
Y
Y
Varner
G
G
Varvell
K E
KE
Wang
C H
CH
Wang
M-Z
MZ
Watanabe
Y
Y
Yabsley
B D
BD
Yamada
Y
Y
Yamaguchi
A
A
Yamashita
Y
Y
Yamauchi
M
M
Yang
Heyoung
H
Ying
J
J
Zhang
Z P
ZP
Zhilich
V
V
Ziegler
T
T
Zontar
D
D
Zürcher
D
D