Related papers: Feasibility study of the eta-prime -> pi+pi-pi0 de…
One of the objectives of the physics programme of the WASA-at-COSY facility is to study the isospin violating eta hadronic decays into pi+pi-pi0$ systems driven by the term of QCD Lagrangian which depends on the d and u quark mass…
Isospin violating hadronic decays of the \eta and \eta' mesons into 3\pi mesons are driven by a term in the QCD Lagrangian proportional to the mass difference of the d and u quarks. The source giving large yield of the mesons for such decay…
An exclusive measurement of the decay eta --> pi+ pi- gamma has been performed at the WASA facility at COSY. The eta mesons were produced in the fusion reaction pd --> 3He X at a proton beam momentum of 1.7 GeV/c. Efficiency corrected…
It is known that the Standard Model does not describe all phenomena related to subatomic particles. This thesis presents feasibility studies of the measurement of eta meson decay using WASA-at-COSY detector which tests predictions of the…
The upper limit of the total cross section for quasi-free pn -> pn eta-prime reaction has been determined in the excess energy range near the kinematic threshold. The measurement has been carried out at the COSY-11 detection setup using a…
Since the eta meson is a short-lived neutral particle, it is not possible to investigate its structure via classical methods of particle scattering. To learn about its quark wave function, one studies those decay processes of this meson in…
The production of eta mesons has been measured in the proton-proton interaction close to the reaction threshold using the COSY-11 internal facility at the cooler synchrotron COSY. Total cross sections were determined for eight different…
At the turn of October and November 2008, the WASA-at-COSY collaboration performed an experiment to collect data on the eta meson decays in pd-->3He eta reactions. This report presents results of a study of the eta-->e+e-g conversion decay.…
Charge conjugation C is one of the fundamental symmetries in nature which transforms particles into antiparticles. This symmetry was studied in weak interaction where it is fully violated, but it is poorly known in the strong and…
We study the inclusive near-threshold production of $\eta^\prime$ mesons in $\pi^-$ meson-nucleus reactions on the basis of the first-collision model relying on the nuclear spectral function and including incoherent processes of…
Recent results obtained by the COSY-11 collaboration concerning the production of eta and eta' mesons in the pp --> pp Meson reaction are presented. A comparison of the production amplitude for the pi(0), eta and eta' mesons at the same…
Intensive quest for the eta and eta' bound states is currently ongoing at both theoretical and experimental levels e.g. at COSY, ELSA, GSI, JINR, JPARC, LPI, and MAMI. These studies were already supported by data provided by the COSY-11…
The analysing power measurements for the p(pol)p -> pp eta reaction studied in this dissertation are used in the determination of the reaction mechanism of the eta meson production in nucleon-nucleon collisions. Measurements have been…
The WASA-at-COSY experiment has collected $3\times10^{7}$ events with $\eta$-mesons produced via the reaction $pd\rightarrow{^{3}\textrm{He}}\eta$ at $\textrm{T} = 1.0 \textrm{GeV}$. Using this data set, we evaluate the branching ratios of…
The cross sections of the pd -> 3He eta, pd -> 3He pi0 pi0 pi0 and pd -> 3He pi+ pi- pi0 reactions have been measured at beam kinetic energies T_p= 1360 MeV and T_p= 1450 MeV using the CELSIUS/WASA detector setup. At both energies, the…
The article describes experimental status of EtaPrime->Pi+Pi-Eta and EtaPrime->Pi+Pi-Pi0 decays. A theoretical framework used for description of the decays mechanism is also reviewed. The possibilities for the measurements with WASA-at-COSY…
The pp-> pp eta reaction was investigated at excess energies of 15 MeV and 72 MeV using the azimuthally symmetric WASA detector and a polarized proton beam of the Cooler Synchrotron COSY. The aim of the studies is the determination of…
Measurements on the eta meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY Juelich. Here we present preliminary results on total and differential cross sections for the pd --> 3He eta…
The low emittance and small momentum spread of the proton and deuteron beams of the Cooler Synchrotron COSY combined with the high mass resolution of the COSY-11 detection system permit to study the creation of mesons in the nucleon-nucleon…
Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high degree of the polarized proton beam of COSY, the reaction pp{\to} pp{\eta} has been measured close to threshold to explore the analyzing…