Study of theηmeson production with the polarised proton beam

Abstract

The azimuthally symmetric WASA detector and the polarised proton beam of COSY, enable investigations of energy and angular dependence of the beam analysing power in the pp → ppη reaction. The aim of the studies is the determination of the partial wave contributions via interference terms which are inaccessible from spin averaged observables. The partial wave decomposition is mandatory for the understanding of the reaction dynamics and for the determination of the η-proton interaction, independently of the theoretical paradigm used.

Determination of the COSY Proton Beam Polarization Using the WASA Detector

“…In order to determine A y more accurately, the axially symmetric WASA detector [38] and the vertically polarized proton beam of COSY have been used to collect a high statistics data sample. An experiment was conducted for the beam momenta of 2026 MeV/c and 2188 MeV/c which correspond to excess energies of 15 MeV and 72 MeV, respectively [35,39]. The trigger was set to select events corresponding to the pp → ppη and pp → pp reactions.…”

Polarization determination for the studies of the eta meson production

“…So far, a high statistics measurement of the pp → pp reaction was made with the large acceptance and symmetric WASA detector [5] installed on the COSY accelerator. The measurement was conducted for beam momenta of 2026 MeV/c and 2188 MeV/c [6] which correspond to excess energies of 15 MeV and 72 MeV, respectively. Proton ejectiles were registered in the forward part of the WASA detector, while the η meson decay products (e.g.…”

Determination of the analysing power for the $\vec p$$p$ $\rightarrow pp\eta$ reaction using WASA-at-COSY detector system

“…In November 2010 the high statistics sample of pp → ppη reaction has been collected using the azimuthally symmetric WASA-at-COSY detector [18]. Measurements were taken with two beam momenta of 2026 MeV/c and 2188 MeV/c, corresponding to 15 MeV and 72 MeV excess energies, respectively.…”