Search for the eta-mesic helium at COSY

We review status and perspectives of the search of the eta-mesic helium at the cooler synchrotron COSY.Comment: Invited talk at the Excited QCD 09 Workshop, 8-14 February 2009, Zakopane, Poland, 6 page

Search for the eta-mesic nuclei by means of COSY-11, WASA-at-COSY and COSY-TOF detector systems

We review status and perspectives of the search for the light eta-mesic nuclei using COSY-11, WASA-at-COSY and COSY-TOF detector systems.Comment: Invited talk at the International Symposium on Mesic Nuclei, Krakow, 16 June 201

Combined analysis of the K+K−K^{+}K^{-} interaction using near threshold pp→ppK+K−pp \to ppK^+K^- data

The $K^{+}K^{-}$ final state interaction was investigated based on both the $K^{+}K^{-}$ invariant mass distributions measured at excess energies of Q = 10 and 28 MeV and the near threshold excitation function for the $pp \to ppK^{+}K^{-}$ reaction. The $K^+K^-$ final state enhancement factor was parametrized using the effective range expansion. The effective range of the $K^+K^-$ interaction was estimated to be: $\mathrm{Re}(b_{K^{+}K^{-}}) = -0.1 \pm 0.4_{stat} \pm 0.3_{sys} \mathrm{fm}$ and $\mathrm{Im}(b_{K^{+}K^{-}}) = 1.2^{+0.1_{stat}+0.2_{sys}}_{-0.2_{stat}-0.0_{sys}} \mathrm{fm}$, and the determined real and imaginary parts of the $K^+K^-$ scattering length amount to: $|\mathrm{Re}(a_{K^{+}K^{-}})| = 8.0^{+6.0_{stat}}_{-4.0_{stat}} \mathrm{fm}$ and $\mathrm{Im}(a_{K^{+}K^{-}}) = 0.0^{+20.0_{stat}}_{-5.0_{stat}} \mathrm{fm}$.Comment: 5 pages, 3 figures, article accepted for publication in Phys. Rev.

Study of the eta meson production with the polarised proton beam

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 --> ppeta 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 eta-proton interaction, independently of the theoretical paradigm used.Comment: To be published in J. Phys. Conf. Ser. in the second quarter of 201

Etaprime and Eta Mesons with Connection to Anomalous Glue

We review the present understanding of etaprime and eta meson physics and these mesons as a probe of gluon dynamics in low-energy QCD. Recent highlights include the production mechanism of eta and etaprime mesons in proton-nucleon collisions from threshold to high-energy, the etaprime effective mass shift in the nuclear medium, searches for possible eta and etaprime bound states in nuclei as well as precision measurements of eta decays as a probe of light-quark masses. We discuss recent experimental data, theoretical interpretation of the different measurements and the open questions and challenges for future investigation.Comment: Review, 25 pages, 11 figures, to appear in Reviews of Modern Physic

Multimeson production in pp interactions as a background for eta and eta' decays

Multimeson production in pp interactions comprises important background for eta, omega and eta' mesons production experiments and for the studies of their decays planned with WASA detector at COSY. The available information about the reactions is summarized and the need for efforts to describe the processes is stressed.Comment: Proceedings of MENU07 Conference Julich, Germany 200

Luminosity determination for the deutron-deutron reactions using free and quasi-free reactions with WASA-at-COSY detector

Two methods of the luminosity determination for the experiment performed by WASA collaboration to search for $^{4} {-0.03cm}{He}$-$\eta$ bound state are presented. During the measurement the technique of continous change of the beam momentum in one accelerator cycle (called ramped beam) was applied. This imposes the requirement to determine not only the total integrated luminosity, but also its variation as a function of the beam momentum.Comment: Symposium on Applied Nuclear Physics and Innovative Technologies, Krakow (Poland), 24-27.09.201

Study of the Decoherence of Entangled Kaons by the Interaction with Thermal Photons

The KLOE-2 detector is a powerful tool to study the temporal evolution of quantum entangled pairs of kaons. The accuracy of such studies may in principle be limited by the interaction of neutral kaons with thermal photons present inside the detector. Therefore, it is crucial to estimate the probability of this effect and its influence on the interference patterns. In this paper we introduce the phenomenology of the interaction of photons with neutral kaons and present and discuss the obtained quantitative results.Comment: Proceeding from 2nd Young Researchers Workshop: Physics Challenges in the LHC Era, Frascati, May 10 and 13, 2010; 6 pages, 4 figure

Proton spin structure and the axial U(1) problem

We emphasise the relation between the spin structure of the proton and the axial U(1) problem. New experiments motivated by the proton spin problem which could shed light on the nature of U(1) symmetry breaking in QCD are discussed.Comment: Invited talk at the Workshop on the Spin Structure of the Proton and Polarized Collider Physics, Trento (July 23-28, 2001), 6 pages, 1 figur