Hydrodynamical analysis of symmetric nucleus-nucleus collisions at CERN/SPS energies

We present a coherent theoretical study of ultrarelativistic heavy-ion data obtained at the CERN/SPS by the NA35/NA49 Collaborations using 3+1-dimensional relativistic hydrodynamics. We find excellent agreement with the rapidity spectra of negative hadrons and protons and with the correlation measurements in two experiments: $S+S$ at 200 $AGeV$ and $Pb+Pb$ at 160 $AGeV$ (preliminary results). Within our model this implies that for $Pb+Pb$ ($S+S$) a quark-gluon-plasma of initial volume 174 $fm^3$ (24 $fm^3$) with a lifetime 3.4 $fm/c$ (1.5 $fm/c$) was formed. It is found that the Bose-Einstein correlation measurements do not determine the maximal effective radii of the hadron sources because of the large contributions from resonance decay at small momenta. Also within this study we present an NA49 acceptance corrected two-pion Bose-Einstein correlation function in the invariant variable, $Q_{inv}$.Comment: 21 pages, 11 Postscript figures (1 File, 775654 Bytes, has to be requested for submission via e.mail from [email protected]

Confirmation of a pi_1^0 Exotic Meson in the \eta \pi^0 System

The exclusive reaction $\pi^- p \to \eta \pi^0 n$, $\eta \to \pi^+ \pi^- \pi^0$ at 18 GeV$/c$ has been studied with a partial wave analysis on a sample of 23~492 $\eta \pi^0 n$ events from BNL experiment E852. A mass-dependent fit is consistent with a resonant hypothesis for the $P_+$ wave, thus providing evidence for a neutral exotic meson with $J^{PC} = 1^{-+}$, a mass of $1257 \pm 20 \pm 25$ MeV$/c^2$, and a width of $354 \pm 64 \pm 60$ MeV$/c^2$. New interpretations of the meson exotics in neutral $\eta \pi^0$ system observed in E852 and Crystal Barrel experiments are discussed.Comment: p3, rewording the paragraph (at the bottom) about the phase variations. p4, rewording paragrath "The second method ..." . p4, at the bottom of paragrath "The third method ..." added consistent with the results of methods 1 and 2

The effect of weathering on U-Th-Pb and oxygen isotope systems of ancient zircons from the Jack Hills, Western Australia.

We report the result of a SIMS U–Th–Pb and O–OH study of 44 ancient zircons from the Jack Hills in Western Australia with ages ranging from 4.3 Ga to 3.3 Ga. We have investigated the behaviour of oxygen isotopes and water in the grains by determining δ18O and OH values at a number of locations on the polished surfaces of each grain. We have divided the zircons into five groups on the basis of their U–Th–Pb and OH-oxygen isotopic behaviour. The first group has concordant U–Th–Pb ages, minimal common Pb, δ18O values consistent with zircons derived from mantle source rocks and no detectable OH content. U–Th–Pb systems in zircons from Groups 2, 3 and 4 vary from concordant to extremely discordant where influenced by cracks. Discordia intercepts with concordia at approximately zero Ma age are interpreted as disturbance of the zircon U–Th–Pb systems by weathering solutions during the extensive, deep weathering that has affected the Archean Yilgarn Craton of Western Australia since at least the Permian. Weathering solutions entering cracks have resulted in an influx of Th and U. δ18O values of Group 2 grains fall approximately within the “mantle” range and OH is within background levels or slightly elevated. δ18O values of Group 3 grains are characterised by an initial trend of decreasing δ18O with increasing OH content. With further increase in OH this trend reverses and δ18O becomes heavier with increasing OH. Group 4 grains have a distinct trend of increasing δ18O with increasing OH. These trends are explained in terms of the reaction of percolating water with the metamict zircon structure and appear to be independent of analytical overlap with cracks. Group five zircons are characterised by U–Pb systems that appear to consist of more than one age but show only minor U–Pb discordance. Nevertheless trends in δ18O versus OH in this group of grains resemble trends seen in the other groups. The observed trends of δ18O with OH in the Jack Hills zircons are similar to those reported in a previous study of zircons from an Archean granite from south-western Australia

Long-range rapidity correlations between mean transverse momenta in the model with string fusion

The long-range correlation between mean-event transverse momenta, being robust against the volume fluctuations and the details of the centrality determination, enables to obtain the signatures of string fusion at the initial stage of hadronic interaction in relativistic heavy ion collisions. The dependence of the correlation strength between mean-event transverse momenta on the collision centrality and initial energy is analyzed in a simple model with quark-gluon string fusion on the transverse lattice. It is shown that above RHIC energy the dependence reveals the decline of the correlation coefficient for most central collisions, reflecting the attenuation of color field fluctuations due to the string fusion at large string density. It is also found that contrary to the correlation between transverse momenta of single particles the strength of the correlation between mean-event transverse momenta of particles in two separated rapidity intervals is not decreasing with the total number of produced strings, remaining significant even in the case of Pb-Pb collisions, in which the total number of strings can reach several thousand

ЭТНИЧЕСКОЕ И РЕЛИГИОЗНОЕ МНОГООБРАЗИЕ РОССИИ

Коллективная монография представляет фундаментальное междисциплинарное исследование для ответа на вопрос, в какой мере культурная сложность российского общества является потенциалом развития и каковы возможные риски. Общероссийский контекст объясняет историческую и современную динамику полиэтничного состава населения и характер межэтнических отношений, а также государственного устройства и управления в Российской Федерации. Рассмотрены вопросы формирования гражданской и этнической идентичности россиян. Раскрываются темы формирования историко-культурных брендов регионов как ресурс развития, проблемы языковой политики в сфере образования, аспекты религиозной ситуации. Содержится анализ современной ситуации на Северном Кавказе, в Крыму, других российских регионах,положение коренных малочисленных народов Севера и Сибири, проблемы цыганского населения и мигрантов. Рекомендации направлены на учет и обеспечение прав и запросов российских граждан в сфере этнокультурных и религиозных отношений. Труд написан ведущими российскими этнологами, социологами, религиоведами в рамках проекта Российского фонда фундаментальных исследований №15-31-11109/17-ОГОН. Материалы содержат новое научное знание об этнокультурном облике России и представляют интерес для ученых гуманитарных дисциплин, преподавателей и учащихся вузов, специалистов в области реализации государственной этнокультурной, языковой и миграционной политики