27 research outputs found
Strange meson production in Al+Al collisions at 1.9A GeV
The production of K, K and (1020) mesons is studied in Al+Al
collisions at a beam energy of 1.9A GeV which is close or below the production
threshold in NN reactions. Inverse slopes, anisotropy parameters, and total
emission yields of K mesons are obtained. A comparison of the ratio of
kinetic energy distributions of K and K mesons to the HSD transport
model calculations suggests that the inclusion of the in-medium modifications
of kaon properties is necessary to reproduce the ratio. The inverse slope and
total yield of mesons are deduced. The contribution to K production
from meson decays is found to be [17 3 (stat) (syst)]
%. The results are in line with previous K and data obtained for
different colliding systems at similar incident beam energies.Comment: 16 pages, 11 figure
Centrality dependence of subthreshold meson production in Ni+Ni collisions at 1.9A GeV
We analysed the meson production in central Ni+Ni collisions at the
beam kinetic energy of 1.93A GeV with the FOPI spectrometer and found the
production probability per event of . This new data point allows for the first time
to inspect the centrality dependence of the subthreshold meson
production in heavy-ion collisions. The rise of meson multiplicity per
event with mean number of participants can be parameterized by the power
function with exponent . The ratio of to
production yields seems not to depend within the experimental
uncertainties on the collision centrality, and the average of measured values
was found to be .Comment: 9 pages, 5 figure
Systematics of pion emission in heavy ion collisions in the 1A GeV regime
Using the large acceptance apparatus FOPI, we study pion emission in the
reactions (energies in GeV/nucleon are given in parentheses): 40Ca+40Ca (0.4,
0.6, 0.8, 1.0, 1.5, 1.93), 96Ru+96Ru (0.4, 1.0, 1.5), 96Zr+96Zr (0.4, 1.0,
1.5), 197Au+197Au (0.4, 0.6, 0.8, 1.0, 1.2, 1.5). The observables include
longitudinal and transverse rapidity distributions and stopping, polar
anisotropies, pion multiplicities, transverse momentum spectra, ratios for
positively and negatively charged pions of average transverse momenta and of
yields, directed flow, elliptic flow. The data are compared to earlier data
where possible and to transport model simulations.Comment: 56 pages,42 figures; to be published in Nuclear Physics
Influence of mesons on negative kaons in Ni+Ni collisions at 1.91A GeV beam energy
and K mesons from Ni+Ni collisions at the beam energy of 1.91A GeV
have been measured by the FOPI spectrometer, with a trigger selecting central
and semi-central events amounting to 51% of the total cross section. The phase
space distributions, and the total yield of K, as well as the kinetic
energy distribution and the total yield of mesons are presented. The
\K ratio is found to be , meaning that about 22% of K mesons originate from the
decays of mesons, occurring mostly in vacuum. The inverse slopes of
direct kaons are up to about 15 MeV larger than the ones extracted within the
one-source model, signalling that a considerable share of gap between the
slopes of K and K could be explained by the contribution of
mesons to negative kaons.Comment: 8 pages, 6 figure
The verification of the zinc-lead resources of the Zawiercie I, Zawiercie II, Gołuchowice and Marciszów deposits (Silesian-Cracow Triassic Province)
Zasoby bilansowe złóż: Zawiercie I, Zawiercie II, Gołuchowice i Marciszów wynoszą obecnie ok. 50 mln Mg rudy zawierającej ok. 2,2 mln Mg cynku i ok. 0,8 mln Mg ołowiu. Do obliczeń zasobów wykorzystano archiwalne wyniki prac dokumentacyjnych, aktualne kryteria bilansowości oraz nową metodykę, tzw. promienia autokorelacji. Rudy siarczkowe Zn–Pb występują głównie w okruszcowanych utworach triasu środkowego określanych jako dolomity kruszconośne, obejmujące warstwy gogolińskie i górażdżańskie. Największe udokumentowane geologiczne zasoby bilansowe (w kat. C1 + C2) występują w złożach: Gołuchowice (ok. 28 mln Mg rudy Zn–Pb, w tym ok. 0,95 mln Mg Zn i 0,23 mln Mg Pb) i Zawiercie I (ok. 17 mln Mg rudy Zn–Pb, w tym ok. 1 mln Mg Zn i 0,4 mln Mg Pb). W złożach Zawiercie II i Marciszów zasoby rud oraz obszary złożowe uległy, w stosunku do wcześniejszych wyliczeń opartych na dawnych kryteriach i innej metodyce (tzw. wieloboków Bołdyriewa), znacznemu zmniejszeniu, głównie ze względu na zbyt słabe rozpoznanie siatką wierceń (kat. C2 + D). Obecne, zasoby niezagospodarowanych czterech złóż rejonu zawierciańskiego stanowią ok. 52,4% całkowitych zasobów rud Zn–Pb regionu śląsko-krakowskiego. Złoże Zn–Pb Gołuchowice po skreśleniu z Bilansu zasobów kopalin i wód podziemnych w 1993 r., w wyniku przeprowadzonej weryfikacji zasobów, zostało przywrócone do Bilansu w 2009 r. (wg stanu na 31.12.2008 r.).The total indicated mineral resources calculated for the Zn–Pb deposits of Zawiercie I, Zawiercie II, Gołuchowice and Marciszów are ca. 50 millionMgof sulphide ores containing ca. 2.2 millionMgof zinc and ca. 0.8 millionMgof lead. Recalculation of the resources was based on archive data collected in the second half of the 20th century, current balance criteria, and a new method called radius of autocorrelation. Zinc-lead sulphide ores occur mainly in Middle-Triassic rocks represented by ore-bearing dolomites, which consist of the Gogolin and Góra¿d¿e Beds. The greatest documented recoverable resources (C1+ C2 categories according to the Polish terminology) occur in the Gołuchowice (ca. 28 million Mg of Zn–Pb ores; 0.95 million Mg of Zn and 0.23 million Mg of Pb) and Zawiercie I deposits (ca. 17 million Mg of Zn–Pb ores, including ca. 1 million Mg of Zn and 0.4 million Mg of Pb). Inferred mineral resources and volume of ore fields in the Zawiercie II and Marciszów Zn–Pb deposits decreased as compared with the previous estimations based on the old economic criteria and a different method of ore resources calculation (Bołdyriew’s polygons method). It is mostly due to very weak drilling prospecting (C2 + D categories). The total present value of indicated and inferred mineral resources of these four deposits constitute ca. 52.4% of total Zn–Pb ore resources of the Silesian-Cracow Province. The Gołuchowice Zn–Pb deposit was deleated from the Balance of raw material and groundwater resources in Poland in 1993 and restored in 2009 (as of 31.12.2008)