The production of $\Sigma^0$ hyperons in proton proton collisions at a beam
kinetic energy of 3.5 GeV impinging on a liquid hydrogen target was
investigated using data collected with the HADES setup. ...The total production
cross section is found to be $\mathrm{\sigma (pK^{+}\Sigma^{0}) \mu b = 17.7
\pm 1.7 (stat) \pm 1.6 (syst)}$. Differential cross section distributions of
the exclusive channel $\mathrm{pp \rightarrow pK^{+}\Sigma^{0}}$ were analyzed
in the center-of-mass, Gottfried-Jackson and helicity reference frames for the
first time at the excess energy of 556 MeV. The data support the interplay
between pion and kaon exchange mechanisms and clearly demonstrate the
contribution of interfering nucleon resonances decaying to
$\mathrm{K^{+}\Sigma^{0}}$. The Bonn-Gatchina partial wave analysis was
employed to analyse the data. Due to the limited statistics, it was not
possible to obtain an unambiguous determination of the relative contribution of
intermediate nucleon resonances to the final state. However nucleon resonances
with masses around 1.710 $\mathrm{GeV/c^{2}}$ ($\mathrm{N^{*}(1710)}$) and
1.900 $\mathrm{GeV/c^{2}}$ ($\mathrm{N^{*}(1900)}$ or
$\mathrm{\Delta^{*}(1900)}$) are preferred by the fit.
Microstructure, revealed by X-ray diffraction, transmission electron microscopy and Moessbauer spectroscopy, and magnetic properties such as magnetic susceptibility, its disaccommodation, core losses ...and approach to magnetic saturation in bulk amorphous (Fe sub(0.61Co) sub(0).10Zr sub(0.025Hf) sub(0).025Ti sub(0.02W) sub(0).0 2B sub(0.20)) sub(1)00-xY sub(x (x=0, 2, 3 or 4) alloys in the as-cast state and after the annealing in vacuum at 720 K for 15 min. are studied. The investigated alloys are ferromagnetic at room temperature. The average hyperfine field induction decreases with Y concentration. Due to annealing out of free volumes its value increases after the heat treatment of the samples. The magnetic susceptibility and core losses point out that the best thermal stability by the amorphous (Fe) sub(0).61Co sub(0.10Zr) sub(0).025Hf sub(0.025Ti) sub(0).02W sub(0.0 2B) sub(0).20) sub(97Y) sub(3) alloy is exhibited. Moreover, from Moessbauer spectroscopy investigations it is shown that the mentioned above alloy is the most homogeneous. The atom packing density increases with Y concentration, which is proved by the magnetic susceptibility disaccommodation and approach to magnetic saturation studies.
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at inline image have been measured by the ALICE Collaboration at the LHC. The data are presented for central and ...peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in
The production of \(\Sigma^0\) hyperons in proton proton collisions at a beam kinetic energy of 3.5 GeV impinging on a liquid hydrogen target was investigated using data collected with the HADES ...setup. The total production cross section is found to be \(\mathrm{\sigma (pK^{+}\Sigma^{0}) \mu b = 17.7 \pm 1.7 (stat) \pm 1.6 (syst)}\). Differential cross section distributions of the exclusive channel \(\mathrm{pp \rightarrow pK^{+}\Sigma^{0}}\) were analyzed in the center-of-mass, Gottfried-Jackson and helicity reference frames for the first time at the excess energy of 556 MeV. The data support the interplay between pion and kaon exchange mechanisms and clearly demonstrate the contribution of interfering nucleon resonances decaying to \(\mathrm{K^{+}\Sigma^{0}}\). The Bonn-Gatchina partial wave analysis was employed to analyse the data. Due to the limited statistics, it was not possible to obtain an unambiguous determination of the relative contribution of intermediate nucleon resonances to the final state. However nucleon resonances with masses around 1.710 \(\mathrm{GeV/c^{2}}\) (\(\mathrm{N^{*}(1710)}\)) and 1.900 \(\mathrm{GeV/c^{2}}\) (\(\mathrm{N^{*}(1900)}\) or \(\mathrm{\Delta^{*}(1900)}\)) are preferred by the fit.
After annealing alloys below crystallization temperatures, the decrease of the average hyperfine field due to the invar effect is observed. At early stages of crystallization, the iron content in the ...amorphous matrix is the same as in the as-quenched state. The amorphous samples show broad disaccommodation spectra with activation energies from 0.6 to 0.9eV. The highest initial magnetic susceptibility was obtained for the nanocrystalline Fe85.4Zr5.8Nb1B6.8Cu1 alloy. However, the best thermal stability of the susceptibility is observed for the Fe85.4Zr6.8B6.8Cu1 alloy.
We stated that crystalline grains in the nanocrystalline alloys obtained by a proper annealing consist of the ordered α-FeCo phase. However, in the partially crystallized alloys during a rapid ...solidification α-FeCo phase is completely disordered. In both, the amorphous and nanocrystalline samples broad disaccommodation spectra are observed. The activation energies of relaxation processes range from 1.00 to 1.34eV and from 1.47 to 1.82eV for the amorphous and nanocrystalline samples, respectively.
PDF
