title: Mechanism of near-threshold production of the eta meson.
abstract: 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.
authors.affiliation: Institute of Physics, Jagellonian University, 30-059 Cracow, Poland.
authors.forename: R
authors.initials: R
authors.lastname: Czyzykiewicz
authors.forename: P
authors.initials: P
authors.lastname: Moskal
authors.forename: H-H
authors.initials: HH
authors.lastname: Adam
authors.forename: A
authors.initials: A
authors.lastname: Budzanowski
authors.forename: E
authors.initials: E
authors.lastname: Czerwiński
authors.forename: D
authors.initials: D
authors.lastname: Gil
authors.forename: D
authors.initials: D
authors.lastname: Grzonka
authors.forename: M
authors.initials: M
authors.lastname: Hodana
authors.forename: M
authors.initials: M
authors.lastname: Janusz
authors.forename: L
authors.initials: L
authors.lastname: Jarczyk
authors.forename: B
authors.initials: B
authors.lastname: Kamys
authors.forename: A
authors.initials: A
authors.lastname: Khoukaz
authors.forename: K
authors.initials: K
authors.lastname: Kilian
authors.forename: P
authors.initials: P
authors.lastname: Klaja
authors.forename: B
authors.initials: B
authors.lastname: Lorentz
authors.forename: W
authors.initials: W
authors.lastname: Oelert
authors.forename: C
authors.initials: C
authors.lastname: Piskor-Ignatowicz
authors.forename: J
authors.initials: J
authors.lastname: Przerwa
authors.forename: B
authors.initials: B
authors.lastname: Rejdych
authors.forename: J
authors.initials: J
authors.lastname: Ritman
authors.forename: T
authors.initials: T
authors.lastname: Sefzick
authors.forename: M
authors.initials: M
authors.lastname: Siemaszko
authors.forename: J
authors.initials: J
authors.lastname: Smyrski
authors.forename: A
authors.initials: A
authors.lastname: Täschner
authors.forename: K
authors.initials: K
authors.lastname: Ulbrich
authors.forename: P
authors.initials: P
authors.lastname: Winter
authors.forename: M
authors.initials: M
authors.lastname: Wolke
authors.forename: P
authors.initials: P
authors.lastname: Wüstner
authors.forename: W
authors.initials: W
authors.lastname: Zipper