Parity-violating electron scattering from 4He and the strange electric form factor of the nucleon.
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 4He at an average scattering angle <theta(lab)> = 5.7 degrees and a four-momentum transfer Q2 = 0.091 GeV2 . From these data, for the first time, the strange electric form factor of the nucleon G(E)s can be isolated. The measured asymmetry of A(PV) = (6.72 +/- 0.84(stat) +/- 0.21(syst) x 10(-6) yields a value of G(E)s = -0.038 +/- 0.042(stat) +/- 0.010(syst), consistent with zero.
California State University, Los Angeles, Los Angeles, California 90032, USA.
K A
KA
Aniol
D S
DS
Armstrong
T
T
Averett
H
H
Benaoum
P Y
PY
Bertin
E
E
Burtin
J
J
Cahoon
G D
GD
Cates
C C
CC
Chang
Y-C
YC
Chao
J-P
JP
Chen
Seonho
S
Choi
E
E
Chudakov
B
B
Craver
F
F
Cusanno
P
P
Decowski
D
D
Deepa
C
C
Ferdi
R J
RJ
Feuerbach
J M
JM
Finn
S
S
Frullani
K
K
Fuoti
F
F
Garibaldi
R
R
Gilman
A
A
Glamazdin
V
V
Gorbenko
J M
JM
Grames
J
J
Hansknecht
D W
DW
Higinbotham
R
R
Holmes
T
T
Holmstrom
T B
TB
Humensky
H
H
Ibrahim
C W
CW
de Jager
X
X
Jiang
L J
LJ
Kaufman
A
A
Kelleher
A
A
Kolarkar
S
S
Kowalski
K S
KS
Kumar
D
D
Lambert
P
P
LaViolette
J
J
LeRose
D
D
Lhuillier
N
N
Liyanage
D J
DJ
Margaziotis
M
M
Mazouz
K
K
McCormick
D G
DG
Meekins
Z-E
ZE
Meziani
R
R
Michaels
B
B
Moffit
P
P
Monaghan
C
C
Munoz-Camacho
S
S
Nanda
V
V
Nelyubin
D
D
Neyret
K D
KD
Paschke
M
M
Poelker
R
R
Pomatsalyuk
Y
Y
Qiang
B
B
Reitz
J
J
Roche
A
A
Saha
J
J
Singh
R
R
Snyder
P A
PA
Souder
R
R
Subedi
R
R
Suleiman
V
V
Sulkosky
W A
WA
Tobias
G M
GM
Urciuoli
A
A
Vacheret
E
E
Voutier
K
K
Wang
R
R
Wilson
B
B
Wojtsekhowski
X
X
Zheng