KKbar molecules with momentum-dependent interactions

It is shown that the momentum-dependent kaon-antikaon interactions generated via vector meson exchange from the standard SU_V(3) x SU_A(3) interaction Lagrangian lead to a non-local potential in coordinate space that can be incorporated without approximation into a non-relativistic version of the Bethe-Salpeter wave equation containing a radial-dependent effective kaon mass appearing in a fully symmetrized kinetic energy operator, in addition to a local potential. Estimates of the mass and decay widths of f_0(980) and a_0(980), considered as KKbar molecules of isospin 0 and 1, as well as for K^+K^- atomic bound states (kaonium) are presented, and compared with previous studies of a similar nature. It is argued that without a better knowledge of hadronic form factors it is not possible to distinguish between the molecular versus elementary particle models for the structure of the light scalar mesons.Comment: 14 pages, 2 tables, 5 figures. Added subsection on s-channel exchange, additional remarks on the possible effect of gluon exchange, and 1 additional figur

Intensity limitations of a gas cell for stopping, storing and guiding of radioactive ions

The possibility to use a gas cell filled by noble gas (He or Ar) for thermalizing, storing and transporting radioactive ions is explored by studying experimentally ion - electron recombination of stable Ni, resonantly ionized by laser light. Combined with a literature study on ionization chambers, especially developed for high-intensity applications, conclusions are drawn on the maximum intensity of the incoming ion beam. A practical limit is encountered when the space-charge induced voltage fully counteract the applied voltage on the electrodes collecting the electrons

HD 178892 - a cool Ap star with extremely strong magnetic field

We report a discovery of the Zeeman resolved spectral lines, corresponding to the extremely large magnetic field modulus =17.5 kG, in the cool Ap star HD 178892. The mean longitudinal field of this star reaches 7.5 kG, and its rotational modulation implies the strength of the dipolar magnetic component Bp>=23 kG. We have revised rotation period of the star using the All Sky Automated Survey photometry and determined P=8.2478 d. Rotation phases of the magnetic and photometric maxima of the star coincide with each other. We obtained Geneva photometric observation of HD 178892 and estimated Teff=7700+/-250 K using photometry and the hydrogen Balmer lines. Preliminary abundance analysis reveals abundance pattern typical of rapidly oscillating Ap stars.Comment: Accepted by Astronomy & Astrophysics; 4 pages, 4 figure

Progress on Neutron-Target Multipoles above 1 GeV

We report a new extraction of nucleon resonance couplings using pi- photoproduction cross sections on the neutron. The world database for the process gn-->pi-p above 1 GeV has quadrupled with the addition of new differential cross sections from the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab in Hall B. Differential cross sections from CLAS have been improved with a new final-state interaction determination using a diagrammatic technique taking into account the SAID phenomenological NN and piN final-state interaction amplitudes. Resonance couplings have been extracted and compared to previous determinations. With the addition of these new cross sections, significant changes are seen in the high-energy behavior of the SAID cross sections and amplitudes.Comment: 4 pages, 3 figures, 1 table; talk given at 12th International Workshop on Meson Production, Properties and Interaction (MESON2012), 31 May - 5 June 2012, Krakow, Poland; will be published online in European Journal Web of Conference

Oscillons in dilaton-scalar theories

It is shown by both analytical methods and numerical simulations that extremely long living spherically symmetric oscillons appear in virtually any real scalar field theory coupled to a massless dilaton (DS theories). In fact such "dilatonic" oscillons are already present in the simplest non-trivial DS theory -- a free massive scalar field coupled to the dilaton. It is shown that in analogy to the previously considered cases with a single nonlinear scalar field, in DS theories there are also time periodic quasibreathers (QB) associated to small amplitude oscillons. Exploiting the QB picture the radiation law of the small amplitude dilatonic oscillons is determined analytically.Comment: extended discussion on stability, to appear in JHEP, 29 pages, 7 figure

Dual Chamber Laser Ion Source at Lisol

A new type of the gas cell for the resonance ionization laser ion source at the Leuven Isotope Separator On Line (LISOL) has been developed and tested at off-line and on-line conditions. Two-step selective laser ionization is applied to produce purified beams of radioactive isotopes. The selectivity of the ion source has been increased by more than one order of magnitude by separation of the stopping and laser ionization regions. This allows to use electrical fields for further ion purification.Comment: 14 figure

Cobalt-based ZIF-68 and ZIF-69 as the precursors of non-platinum electrocatalysts for oxygen reduction

We report the microwave-assisted synthesis of Co-based ZIF-68 and ZIF-69 zeolitic imidazolate frameworks, which were enriched with iron(ii) acetate and 1,10-phenanthroline and then pyrolyzed to form heterogeneous catalysts. The materials demonstrated high activity in oxygen reduction and suitability as Pt-free catalysts for low-temperature fuel cell

Scalar meson production in nucleon-nucleon collisions near threshold

We establish the model-independent spin structure of the matrix elements for the near-threshold scalar meson production in $pp-$ and $np$-collisions, when the final particles are emitted in S-state. Polarization phenomena are derived in a general form. The properties of the $t-$channel dynamics, which is based on different meson exchanges, are studied in terms of the $s-$channel parametrization of the matrix element. The prediction of a 'realistic' model, based on $\pi+\sigma$-exchanges are also presented.Comment: 16 pages 6 figure