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P. Klaja

Publications and source records attributed to P. Klaja.

43 records · Page 3Linked to original sources
arXiv2005

Isospin dependence of the eta' meson production in nucleon--nucleon collisions

According to the quark model, the masses of eta and eta' mesons should be almost equal. However, the empirical values of these masses differ by more than the factor of two. Similarly, though the almost the same quark-antiquark content, the total cross section for the creation of these mesons close to the kinematical thresholds in the pp --> ppX reaction differs significantly. Using the COSY-11 detection setup we intend to determine whether this difference will also be so significant in the case of the production of these mesons in the proton-neutron scattering. Additionally, the comparison of the pp --> pp eta' and pn --> pn eta' total cross sections will allow to learn about the production of the eta' meson in the channels of isospin I = 0 and I = 1 and to investigate aspects of the gluonium component of the eta' meson.

hep-ex↗
arXiv2004

Open strangeness threshold production at COSY-11

The open strangeness production near threshold is investigated at the internal experiment COSY-11 in different reaction channels. Recently, the main focus has been to extend measurements of the hyperon production pp->pK+Lambda/Sigma0 in different isospin channels as well as the associated strangeness production in pp->ppK+K-. The experimental technique is based on the reconstruction of the four momentum for all positively charged ejectiles. Neutrons are detected in addition using a neutral particle detector. The unregistered hyperon or meson is identified by means of the missing mass technique. The present status of the analysis for both reaction channels is presented. In case of the reaction pp->ppK+K-, very preliminary cross sections are shown.

hep-ex↗
arXiv2004

Hadronic interaction of the eta meson with two nucleons

The COSY-11 collaboration has conducted experiments aiming at the determination of the excitation function and phase-space population of the p p --> p p eta reaction close to the kinematical threshold. The precise data obtained with the stochastically cooled proton beam of the cooler synchrotron COSY and the high resolution zero-degree magnetic spectrometer allowed for the observation of the significant deviations - in the shape of the excitation function and two-particle invariant masses - from the predictions based on the assumption that the reaction phase space is homogenously populated. Comparison of the shape of the excitation function for the p p --> p p eta and p p --> p p eta-prime reaction allows to distinquish in the model independent way an influence originating from the proton-proton and proton-eta interaction. For the comparison the full data set from experiments performed at COSY and other laboratories is used.

hep-ex↗
arXiv2004

Towards the excitation function of the pp -> ppK+K- reaction at COSY-11

The ongoing discussion concerning the nature of the scalar resonances f_0(980) and a_0(980) implicated to extend the studies of the pp -> ppK+K- reaction near the production threshold. Furthermore, such elementary production processes allow to study the interaction of the outgoing particles due to their low relative momenta. Therefore, final state interactions in the pK or K Anti-K system can be perfectly studied in such experiments. The acquired data at the excess energies Q=10 and 28 MeV have been taken at COSY-11 and the status of the ongoing analysis will be presented.

nucl-ex↗
arXiv2004

Threshold Hyperon Production at COSY-11

The Lambda, Sigma0 and Sigma+ hyperon production in NN collisions is studied at the COSY - 11 installation in order to investigate the production mechanism as well as to extract information about the Y-N interaction.

nucl-ex↗
arXiv2004

Search for Bremsstrahlung radiation in quasi-free n p --> n p gamma reactions

Due to the high sensitivity of the N N --> N N gamma reaction to the nucleon-nucleon potential, Bremsstrahlung radiation is used as a tool to investigate details of the nucleon-nucleon interaction. Such investigations can be performed at the cooler synchrotron COSY in the Research Centre Juelich, by dint of the COSY-11 detection system. The results of the identification of Bremsstrahlung radiation emitted via the d p --> d p gamma reaction in data taken with a proton target and a deuteron beam are presented and discussed.

hep-ex↗