1,562 research outputs found
Entanglement of qubits via a nonlinear resonator
Coherent coupling of two qubits mediated by a nonlinear resonator is studied.
It is shown that the amount of entanglement accessible in the evolution depends
both on the strength of nonlinearity in the Hamiltonian of the resonator and on
the initial preparation of the system. The created entanglement survives in the
presence of decoherence.Comment: 6 pages, 10 figure
Determination of the total width of the eta' meson
Taking advantage of both the low-emittance proton-beam of the Cooler
Synchrotron COSY and the high momentum precision of the COSY-11 detector
system, the mass distribution of the eta' meson was measured with a resolution
of 0.33 MeV/c^2 (FWHM), improving the experimental mass resolution by almost an
order of magnitude with respect to previous results. Based on the sample of
more than 2300 reconstructed pp --> pp eta' events the total width of the eta'
meson was determined to be 0.226 +- 0.017(stat.) +- 0.014(syst.) MeV/c^2.Comment: 4 pages, 4 figure
Search for the 3He-eta bound state at COSY-11
We have measured excitation function for dp -> ppp_pi- reaction near the eta
production threshold. We observe an enhancement of the counting rate above the
threshold which can originate from the production of the eta meson in the
reaction dp -> 3He eta and its subsequent absorption on neutron in the 3He
nucleus leading to creation of the p_pi- pair.Comment: Presented at 10th International Workshop on Meson Production,
Properties and Interaction (MESON 2008), Cracow, Poland, 6 - 10 June 2008, 4
pages, 4 figures,references adde
Isospin dependence of the eta prime meson production in nucleon-nucleon collisions
A comparison of the close-to-threshold total cross section for the eta prime
production in pp --> pp eta prime and pn --> pn eta prime reactions constitutes
a tool to investigate the eta prime meson structure and the reaction mechanism
in the channels of isospin I=0 and I=1 and may provide insight into the
flavour-singlet (perhaps also into gluonium) content of the eta prime meson. In
this contribution we present preliminary results of measurement of the
quasi-free production of the eta prime meson in the proton-neutron collisions
conducted using the COSY-11 facility.Comment: Presented at 10th International Workshop on Meson Production,
Properties and Interaction (MESON 2008), Cracow, Poland, 6 - 10 June 200
Hadronic interaction of eta and eta-prime mesons with nucleons
Due to their short life-time, flavour-neutral mesons cannot be utilized as
free secondary beams or targets, and therefore a study of their interaction
with nucleons is not possible via direct scattering experiments.
This interaction is, however, accessible via its influence on the energy
dependence - and on the phase space distributions of the cross sections for
reactions in which these mesons are produced.
In case of the p p --> p p eta reaction the experimentally determined
distributions of the differential cross sections close to the production
threshold cannot be described by taking into account the S-wave proton-proton
and proton-eta interaction only. Here we show that the angular distributions
determined at the COSY-11 facility reveal some evidence for P-wave admixture in
the proton-proton subsystem already at an excess energy as low as Q = 15.5 MeV.
We also present that one can estimate the relative strength of the
eta-nucleon and eta-prime-nucleon interactions by comparison of the eta and
eta-prime production yield.Comment: 4 pages, 3 figures, Talk given at 16th International Conference on
Particles and Nuclei (PANIC 02), Osaka, Japan, 30 Sep - 4 Oct 200
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