Helicity dependence of gammap --> Npi below 450 MeV and contribution to the Gerasimov-Drell-Hearn sum rule.
The helicity dependence of the single pion photoproduction on the proton has been measured in the energy range from 200 to 450 MeV for the first time. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam, and a frozen-spin target. The data obtained provide new information for multipole analyses of pion photoproduction and determine the main contributions to the Gerasimov-Drell-Hearn sum rule and the forward spin polarizability gamma(0).
Ahrens
J
J
Institut für Kernphysik, Universität Mainz, D-55099 Mainz, Germany. arends@kph.uni-mainz.de
Altieri
S
S
Annand
J R
JR
Anton
G
G
Arends
H
H
Aulenbacher
K
K
Beck
R
R
Bradtke
C
C
Braghieri
A
A
Degrande
N
N
d'Hose
N
N
Dutz
H
H
Goertz
S
S
Grabmayr
P
P
Hansen
K
K
Harmsen
J
J
von Harrach
D
D
Hasegawa
S
S
Hasegawa
T
T
Heid
E
E
Helbing
K
K
Holvoet
H
H
Van Hoorebeke
L
L
Horikawa
N
N
Iwata
T
T
Jennewein
P
P
Kageya
T
T
Kiel
B
B
Klein
F
F
Kondratiev
R
R
Kossert
K
K
Krimmer
J
J
Lang
M
M
Lannoy
B
B
Leukel
R
R
Lisin
V
V
Matsuda
T
T
McGeorge
J C
JC
Meier
A
A
Menze
D
D
Meyer
W
W
Michel
T
T
Naumann
J
J
Owens
R O
RO
Panzeri
A
A
Pedroni
P
P
Pinelli
T
T
Preobrajenski
I
I
Radtke
E
E