Improved direct measurement of the parity-violation parameter Ab using a mass tag and momentum-weighted track charge.
We present an improved direct measurement of the parity-violation parameter A(b) in the Z boson-b-quark coupling using a self-calibrating track-charge technique applied to a sample enriched in Z-->bb events via the topological reconstruction of the B hadron mass. Manipulation of the Stanford Linear Collider electron-beam polarization permits the measurement of A(b) to be made independently of other Z-pole coupling parameters. From the 1996-1998 sample of 400,000 hadronic Z decays, produced with an average beam polarization of 73.4%, we find A(b)=0.906+/-0.022(stat)+/-0.023(syst).
Nagoya University, Chikusa-ku, Nagoya, 464 Japan.
Kenji
K
Abe
Koya
K
Abe
T
T
Abe
I
I
Adam
H
H
Akimoto
D
D
Aston
K G
KG
Baird
C
C
Baltay
H R
HR
Band
T L
TL
Barklow
J M
JM
Bauer
G
G
Bellodi
R
R
Berger
G
G
Blaylock
J R
JR
Bogart
G R
GR
Bower
J E
JE
Brau
M
M
Breidenbach
W M
WM
Bugg
D
D
Burke
T H
TH
Burnett
P N
PN
Burrows
A
A
Calcaterra
R
R
Cassell
A
A
Chou
H O
HO
Cohn
J A
JA
Coller
M R
MR
Convery
V
V
Cook
R F
RF
Cowan
G
G
Crawford
C J S
CJ
Damerell
M
M
Daoudi
N
N
de Groot
R
R
de Sangro
D N
DN
Dong
M
M
Doser
R
R
Dubois
I
I
Erofeeva
V
V
Eschenburg
S
S
Fahey
D
D
Falciai
J P
JP
Fernandez
K
K
Flood
R
R
Frey
E L
EL
Hart
K
K
Hasuko
S S
SS
Hertzbach
M E
ME
Huffer
X
X
Huynh
M
M
Iwasaki
D J
DJ
Jackson
P
P
Jacques
J A
JA
Jaros
Z Y
ZY
Jiang
A S
AS
Johnson
J R
JR
Johnson
R
R
Kajikawa
M
M
Kalelkar
H J
HJ
Kang
R R
RR
Kofler
R S
RS
Kroeger
M
M
Langston
D W G
DW
Leith
V
V
Lia
C
C
Lin
G
G
Mancinelli
S
S
Manly
G
G
Mantovani
T W
TW
Markiewicz
T
T
Maruyama
A K
AK
McKemey
R
R
Messner
K C
KC
Moffeit
T B
TB
Moore
M
M
Morii
D
D
Muller
V
V
Murzin
S
S
Narita
U
U
Nauenberg
H
H
Neal
G
G
Nesom
N
N
Oishi
D
D
Onoprienko
L S
LS
Osborne
R S
RS
Panvini
C H
CH
Park
I
I
Peruzzi
M
M
Piccolo
L
L
Piemontese
R J
RJ
Plano
R
R
Prepost
C Y
CY
Prescott
B N
BN
Ratcliff
J
J
Reidy
P L
PL
Reinertsen
L S
LS
Rochester
P C
PC
Rowson
J J
JJ
Russell
O H
OH
Saxton
T
T
Schalk
B A
BA
Schumm
J
J
Schwiening
V V
VV
Serbo
G
G
Shapiro
N B
NB
Sinev
J A
JA
Snyder
H
H
Staengle
A
A
Stahl
P
P
Stamer
H
H
Steiner
D
D
Su
F
F
Suekane
A
A
Sugiyama
S
S
Suzuki
M
M
Swartz
F E
FE
Taylor
J
J
Thom
E
E
Torrence
T
T
Usher
J
J
Va'vra
R
R
Verdier
D L
DL
Wagner
A P
AP
Waite
S
S
Walston
A W
AW
Weidemann
E R
ER
Weiss
J S
JS
Whitaker
S H
SH
Williams
S
S
Willocq
R J
RJ
Wilson
W J
WJ
Wisniewski
J L
JL
Wittlin
M
M
Woods
T R
TR
Wright
R K
RK
Yamamoto
J
J
Yashima
S J
SJ
Yellin
C C
CC
Young
H
H
Yuta