Evidence of the purely leptonic decay B- --> tau- nu(tau).
We present the first evidence of the decay B- --> tau- nu(tau), using 414 fb(-1) of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics and measure the branching fraction to be B(B- --> tau- nu(tau)) = (1.79(-0.49) +0.56(stat)(-0.51) +0.46(syst)) x 10(-4). This implies that fB = 0.229(-0.031) +0.036(stat)(-0.037) +0.034(syst) GeV and is the first direct measurement of this quantity.
Ikado
K
K
Nagoya University, Nagoya.
Abe
K
K
Abe
K
K
Adachi
I
I
Aihara
H
H
Akai
K
K
Akemoto
M
M
Anipko
D
D
Arinstein
K
K
Aulchenko
V
V
Aushev
T
T
Aziz
T
T
Bakich
A M
AM
Balagura
V
V
Barbero
M
M
Bay
A
A
Bedny
I
I
Belous
K
K
Bitenc
U
U
Bizjak
I
I
Bondar
A
A
Bozek
A
A
Bracko
M
M
Browder
T E
TE
Chang
P
P
Chen
A
A
Chen
W T
WT
Choi
Y
Y
Cole
S
S
Dalseno
J
J
Danilov
M
M
Dash
M
M
Eidelman
S
S
Epifanov
D
D
Flanagan
J
J
Fratina
S
S
Furukawa
K
K
Gabyshev
N
N
Gershon
T
T
Go
A
A
Gokhroo
G
G
Golob
B
B
Gorisek
A
A
Ha
H
H
Haba
J
J
Hara
K
K
Hara
T
T
Hastings
N C
NC
Hayasaka
K
K
Hayashii
H
H
Hazumi
M
M
Hinz
L
L
Hokuue
T
T
Hoshi
Y
Y
Hou
S
S
Hou
W-S
WS
Iida
N
N
Iijima
T
T
Imoto
A
A
Inami
K
K
Ishikawa
A
A
Ishino
H
H
Itoh
R
R
Iwasaki
M
M
Iwasaki
Y
Y
Kamitani
T
T
Kang
J H
JH
Kataoka
S U
SU
Katayama
N
N
Kawai
H
H
Kawasaki
T
T
Kichimi
H
H
Kikutani
E
E
Kim
H J
HJ
Kim
H O
HO
Kinoshita
K
K
Koiso
H
H
Korpar
S
S
Krizan
P
P
Krokovny
P
P
Kulasiri
R
R
Kumar
R
R
Kuo
C C
CC
Kuzmin
A
A
Kwon
Y-J
YJ
Lange
J S
JS
Leder
G
G
Lee
J
J
Lesiak
T
T
Limosani
A
A
Lin
S-W
SW
Liventsev
D
D
Marlow
D
D
Matsumoto
T
T
Matyja
A
A
McOnie
S
S
Michizono
S
S
Mimashi
T
T
Mitaroff
W
W
Miyabayashi
K
K
Miyata
H
H
Miyazaki
Y
Y
Mizuk
R
R
Nagamine
T
T
Nakamura
I
I
Nakamura
T T
TT
Nakano
E
E
Nakao
M
M
Nishida
S
S
Nitoh
O
O
Noguchi
S
S
Nozaki
T
T
Ogawa
S
S
Ogawa
Y
Y
Ohmi
K
K
Ohshima
T
T
Ohuchi
N
N
Oide
K
K
Okabe
T
T
Okuno
S
S
Olsen
S L
SL
Onuki
Y
Y
Ostrowicz
W
W
Ozaki
H
H
Pakhlov
P
P
Park
C W
CW
Park
H
H
Pestotnik
R
R
Piilonen
L E
LE
Poluektov
A
A
Rozanska
M
M
Sakai
Y
Y
Schietinger
T
T
Schneider
O
O
Schwanda
C
C
Senyo
K
K
Sevior
M E
ME
Shapkin
M
M
Shibuya
H
H
Shidara
T
T
Shwartz
B
B
Sidorov
V
V
Sokolov
A
A
Somov
A
A
Stanic
S
S
Staric
M
M
Stoeck
H
H
Sumisawa
K
K
Sumiyoshi
T
T
Suzuki
S
S
Tajima
O
O
Takasaki
F
F
Tamai
K
K
Tamura
N
N
Tanaka
M
M
Tawada
M
M
Taylor
G N
GN
Teramoto
Y
Y
Tian
X C
XC
Trabelsi
K
K
Tsuboyama
T
T
Tsukamoto
T
T
Uehara
S
S
Uglov
T
T
Ueno
K
K
Unno
Y
Y
Uno
S
S
Usov
Y
Y
Varner
G
G
Villa
S
S
Wang
C C
CC
Wang
C H
CH
Watanabe
Y
Y
Won
E
E
Yabsley
B D
BD
Yamaguchi
A
A
Yamashita
Y
Y
Yamauchi
M
M
Yoshida
M
M
Yusa
Y
Y
Zhang
L M
LM
Zhang
Z P
ZP
Zhilich
V
V
Zürcher
D
D