First measurement of the double spin asymmetry in (-->)e(-->)p-->e(prime)pi(+)n in the resonance region.
The double spin asymmetry in the (-->)e(-->)p --> e(prime)pi(+)n reaction has been measured for the first time in the resonance region for four-momentum transfer Q2 = 0.35-1.5 GeV(2). Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH3 target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with Q(2) of the helicity asymmetry A1 for the F(15)(1680) resonance than expected from the analysis of the unpolarized data.
De Vita
R
R
Istituto Nazionale di Fisica Nucleare, Sezione di Genova, and Dipartimento di Fisica dell'Università, 16146 Genova, Italy.
Anghinolfi
M
M
Burkert
V D
VD
Dodge
G E
GE
Minehart
R
R
Taiuti
M
M
Weller
H
H
Adams
G
G
Amaryan
M J
MJ
Anciant
E
E
Armstrong
D S
DS
Asavapibhop
B
B
Asryan
G
G
Audit
G
G
Auger
T
T
Avakian
H
H
Bagdasaryan
H
H
Ball
J P
JP
Barrow
S
S
Battaglieri
M
M
Beard
K
K
Bektasoglu
M
M
Bianchi
N
N
Biselli
A S
AS
Boiarinov
S
S
Bonner
B E
BE
Bosted
P
P
Bouchigny
S
S
Branford
D
D
Brooks
W K
WK
Bueltmann
S
S
Calarco
J R
JR
Capitani
G P
GP
Carman
D S
DS
Carnahan
B
B
Cazes
A
A
Ciciani
L
L
Cole
P L
PL
Coleman
A
A
Connelly
J
J
Cords
D
D
Corvisiero
P
P
Crabb
D
D
Crannell
H
H
Cummings
J P
JP
De Sanctis
E
E
Degtyarenko
P V
PV
Demirchyan
R
R
Denizli
H
H
Dennis
L
L
Dharmawardane
K V
KV
Dhuga
K S
KS
Djalali
C
C
Doughty
D
D
Dragovitsch
P
P
Dugger
M
M
Dytman
S
S
Eckhause
M
M
Egiyan
H
H
Egiyan
K S
KS
Elouadrhiri
L
L
Empl
A
A
Farhi
L
L
Fatemi
R
R
Feuerbach
R J
RJ
Ficenec
J
J
Forest
T A
TA
Frolov
V
V
Funsten
H
H
Gaff
S J
SJ
Gai
M
M
Garçon
M
M
Gavalian
G
G
Gilad
S
S
Gilfoyle
G P
GP
Giovanetti
K L
KL
Girard
P
P
Golovatch
E
E
Griffioen
K
K
Guidal
M
M
Guillo
M
M
Gyurjyan
V
V
Hadjidakis
C
C
Hancock
D
D
Hardie
J
J
Heddle
D
D
Heimberg
P
P
Hersman
F W
FW
Hicks
K
K
Hicks
R S
RS
Holtrop
M
M
Hu
J
J
Hyde-Wright
C E
CE
Ishkanov
B S
BS
Ito
M M
MM
Jenkins
D
D
Joo
K
K
Kelley
J H
JH
Kellie
J D
JD
Khandaker
M
M
Kim
K Y
KY
Kim
K
K
Kim
W
W
Klein
A
A
Klein
F J
FJ
Klusman
M
M
Kossov
M
M
Kramer
L H
LH
Kuang
Y
Y
Kuhn
S E
SE
Lachniet
J
J
Laget
J M
JM
Lawrence
D
D
Li
Ji
J
Livingston
K
K
Longhi
A
A
Loukachine
K
K
Lucas
M
M
Major
W
W
Manak
J J
JJ
Marchand
C
C
McAleer
S
S
McCarthy
J
J
McNabb
J W C
JW
Mecking
B A
BA
Mestayer
M D
MD
Meyer
C A
CA
Mikhailov
K
K
Mirazita
M
M
Miskimen
R
R
Mokeev
V
V
Muccifora
V
V
Mueller
J
J
Mutchler
G S
GS
Napolitano
J
J
Nelson
S O
SO
Niculescu
G
G
Niculescu
I
I
Niczyporuk
B B
BB
Niyazov
R A
RA
Opper
A K
AK
O'Rielly
G V
GV
Osipenko
M
M
Park
K
K
Pasyuk
E
E
Peterson
G
G
Philips
S A
SA
Pivnyuk
N
N
Pocanic
D
D
Pogorelko
O
O
Polli
E
E
Pozdniakov
S
S
Preedom
B M
BM
Price
J W
JW
Prok
Y
Y
Protopopescu
D
D
Qin
L M
LM
Raue
B A
BA
Reolon
A R
AR
Riccardi
G
G
Ricco
G
G
Ripani
M
M
Ritchie
B G
BG
Rock
S
S
Ronchetti
F
F
Rossi
P
P
Rowntree
D
D
Rubin
P D
PD
Sabatié
F
F
Sabourov
K
K
Salgado
C
C
Sapunenko
V
V
Sargsyan
M
M
Schumacher
R A
RA
Serov
V S
VS
Shafi
A
A
Sharabian
Y G
YG
Shaw
J
J
Skabelin
A V
AV
Smith
E S
ES
Smith
T
T
Smith
L C
LC
Sober
D I
DI
Sorrell
L
L
Spraker
M
M
Stavinsky
A
A
Stepanyan
S
S
Stoler
P
P
Strakovsky
I I
II
Taylor
S
S
Tedeschi
D J
DJ
Thompson
R
R
Todor
L
L
Ungaro
M
M
Vineyard
M F
MF
Vlassov
A V
AV
Wang
K
K
Weinstein
L B
LB
Weisberg
A
A
Weygand
D P
DP
Whisnant
C S
CS
Wolin
E
E
Yegneswaran
A
A
Yun
J
J
Zhang
B
B
Zhao
J
J
Zhou
Z
Z