Test of low-energy theorems for 1H(--> gamma, pi(0))(H)in the threshold hegion.
The photon asymmetry in the reaction 1H(--> gamma,pi(0))(1)H close to threshold has been measured for the first time with the photon spectrometer TAPS using linearly polarized photons from the tagged-photon facility at the Mainz Microtron MAMI. The total and differential cross sections were also measured simultaneously with the photon asymmetry. This allowed determination of the S-wave and all three P-wave amplitudes. The values obtained at threshold are E(0+) = [-1.33+/-0.08(stat)+/-0.03(syst)] x 10(-3)/m(pi(+)), P(1) = [9.47 +/- 0.08(stat) +/- 0.29(syst)] x 10(-3)q/m(2)(pi(+)), P(2) = [-9.46 +/- 0.1(stat) +/- 0.29(syst)] x 10(-3)q/m(2)(pi(+)), and P(3) = [11.48 +/- 0.06(stat) +/- 0.35(syst)] x 10(-3)q/m(2)(pi(+)).
Schmidt
A
A
Institut für Kernphysik, Universität Mainz, D-55099 Mainz, Germany.
Achenbach
P
P
Ahrens
J
J
Arends
H J
HJ
Beck
R
R
Bernstein
A M
AM
Hejny
V
V
Kotulla
M
M
Krusche
B
B
Kuhr
V
V
Leukel
R
R
MacGregor
I J
IJ
McGeorge
J C
JC
Metag
V
V
Olmos De León
V M
VM
Rambo
F
F
Siodlaczek
U
U
Ströher
H
H
Walcher
T
T
Weiss
J
J
Wissmann
F
F
Wolf
M
M