Mechanism of near-threshold production of the eta meson.
Measurements of the analyzing power for the pp-->pp eta reaction have been performed at excess energies of Q=10 and 36 MeV. The determined analyzing power is essentially consistent with zero, implying dominance of the s wave at both excess energies. The angular dependence of the analyzing power, combined with the isospin dependence of the total cross section for the eta meson production in nucleon-nucleon collisions, reveal that the excitation of the nucleon to the S11(1535) resonance is predominantly due to the exchange of the pi meson between the colliding nucleons.
Czyzykiewicz
R
R
Institute of Physics, Jagellonian University, 30-059 Cracow, Poland.
Moskal
P
P
Adam
H-H
HH
Budzanowski
A
A
Czerwiński
E
E
Gil
D
D
Grzonka
D
D
Hodana
M
M
Janusz
M
M
Jarczyk
L
L
Kamys
B
B
Khoukaz
A
A
Kilian
K
K
Klaja
P
P
Lorentz
B
B
Oelert
W
W
Piskor-Ignatowicz
C
C
Przerwa
J
J
Rejdych
B
B
Ritman
J
J
Sefzick
T
T
Siemaszko
M
M
Smyrski
J
J
Täschner
A
A
Ulbrich
K
K
Winter
P
P
Wolke
M
M
Wüstner
P
P
Zipper
W
W