Рослинний покрив урочища “Хілінські гори” на Поліссі

The unique complex of pine forest and mire vegetation of landscape unit Khilinski Gory are characterized. New locations of rare species of flora Polesie (Jurinea cyanoides, Luzula sylvatica, Otites eugeniae, Polypodium vulgare, Tragopogon ukrainicus) are described. Recommendations for vegetation protection are proposed.Охарактеризовано унікальний комплекс борової та болотної рослинності урочища “Хілінські Гори”. Описано нові місцезнаходження рідкісних видів флори Полісся (Jurinea cyanoides, Luzula sylvatica, Otites eugeniae, Polypodium vulgare, Tragopogon ukrainicus). Запропоновано рекомендації щодо охорони рослинного покриву урочища

Нові місцезнаходження рідкісних видів вищих рослин у південно-західній частині Житомирського Полісся

New locations of 8 rare species of higher plants in south-west region of Zhytomyr Polesye are described. Among them 2 species of moss – Cinсlidotus fontinaloides (Hedw.) A. Beauv., Fontinalis antipiretica Hedw., 2 species of ferns – Matteuccia struthiopteris (L.) Tod., Phegopteris connectilis (Michx.) Watt and 4 species of flowering plants – Phyteuma spicatum L., Polemonium caeruleum L., Genista germanica L., Dactylorhiza majalis (Reichenb.) P.F. Hunt et Summerhayes. Geographical distribution and habitats of these species in territory of Zhytomyr Polesye are considered.Описано нові місцезнаходження 8 рідкісних видів вищих рослин у південно-західній частині Житомирського Полісся. Серед них 2 види мохів – Cinсlidotus fontinaloides (Hedw.) A. Beauv., Fontinalis antipiretica Hedw., 2 види папоротей – Matteuccia struthiopteris (L.) Tod., Phegopteris connectilis (Michx.) Watt і 4 види покритонасінних рослин – Phyteuma spicatum L., Polemonium caeruleum L., Genista germanica L., Dactylorhiza majalis (Reichenb.) P.F. Hunt et Summerhayes. Розглянуто географічне поширення цих видів у регіоні та охарактеризовано екологоценотичні умови їхніх місцезростань

Study of the process of thermal dissociation of tantal pentachloride in vacuum

The dependence of the degree of dissociation of TaCl₅α(T, P) vapors on the temperature in the range of 1470...1820 K in a vacuum of 1.33·10⁻² Pa was by using of equilibrium chemical thermodynamics obtained. The experimental data on the dependence of αex(Т, Р) on temperature and vapor mass flow TaCl₅ were analyzed and compared with calculations.У рамках рівноважної хімічної термодинаміки отримана залежність ступеня дисоціації парів TaCl₅α(T, P) від температури в інтервалі 1470…1820 К і вакуумі 1,33·10⁻² Па. Проаналізовано та порівняно з розрахунковими експериментальні дані залежності αексп(Т, Р) від температури і масового потоку парів TaCl₅.В рамках равновесной химической термодинамики получена зависимость степени диссоциации паров TaCl₅α(T, P) от температуры в интервале 1470…1820 К и вакууме 1,33·10⁻² Па. Проанализированы и сравниваются расчетные данные с экспериментальными данными зависимости αэксп(Т, Р) от температуры и массового потока паров TaCl₅

Heavy Quarks and Heavy Quarkonia as Tests of Thermalization

We present here a brief summary of new results on heavy quarks and heavy quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma Thermalization" Workshop in Vienna, Austria in August 2005, directly following the International Quark Matter Conference in Hungary.Comment: 8 pages, 5 figures, Quark Gluon Plasma Thermalization Workshop (Vienna August 2005) Proceeding

Single Electrons from Heavy Flavor Decays in p+p Collisions at sqrt(s) = 200 GeV

The invariant differential cross section for inclusive electron production in p+p collisions at sqrt(s) = 200 GeV has been measured by the PHENIX experiment at the Relativistic Heavy Ion Collider over the transverse momentum range $0.4 <= p_T <= 5.0 GeV/c at midrapidity (eta <= 0.35). The contribution to the inclusive electron spectrum from semileptonic decays of hadrons carrying heavy flavor, i.e. charm quarks or, at high p_T, bottom quarks, is determined via three independent methods. The resulting electron spectrum from heavy flavor decays is compared to recent leading and next-to-leading order perturbative QCD calculations. The total cross section of charm quark-antiquark pair production is determined as sigma_(c c^bar) = 0.92 +/- 0.15 (stat.) +- 0.54 (sys.) mb.Comment: 329 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Nuclear Modification of Electron Spectra and Implications for Heavy Quark Energy Loss in Au+Au Collisions at sqrt(s_NN)=200 GeV

The PHENIX experiment has measured mid-rapidity transverse momentum spectra (0.4 < p_T < 5.0 GeV/c) of electrons as a function of centrality in Au+Au collisions at sqrt(s_NN)=200 GeV. Contributions from photon conversions and from light hadron decays, mainly Dalitz decays of pi^0 and eta mesons, were removed. The resulting non-photonic electron spectra are primarily due to the semi-leptonic decays of hadrons carrying heavy quarks. Nuclear modification factors were determined by comparison to non-photonic electrons in p+p collisions. A significant suppression of electrons at high p_T is observed in central Au+Au collisions, indicating substantial energy loss of heavy quarks.Comment: 330 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Dilepton mass spectra in p+p collisions at sqrt(s)= 200 GeV and the contribution from open charm

The PHENIX experiement has measured the electron-positron pair mass spectrum from 0 to 8 GeV/c^2 in p+p collisions at sqrt(s)=200 GeV. The contributions from light meson decays to e^+e^- pairs have been determined based on measurements of hadron production cross sections by PHENIX. They account for nearly all e^+e^- pairs in the mass region below 1 GeV/c^2. The e^+e^- pair yield remaining after subtracting these contributions is dominated by semileptonic decays of charmed hadrons correlated through flavor conservation. Using the spectral shape predicted by PYTHIA, we estimate the charm production cross section to be 544 +/- 39(stat) +/- 142(syst) +/- 200(model) \mu b, which is consistent with QCD calculations and measurements of single leptons by PHENIX.Comment: 375 authors from 57 institutions, 18 pages, 4 figures, 2 tables. Submitted to Physics Letters B. v2 fixes technical errors in matching authors to institutions. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Inclusive cross section and double helicity asymmetry for \pi^0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton

The PHENIX experiment presents results from the RHIC 2005 run with polarized proton collisions at sqrt(s)=200 GeV, for inclusive \pi^0 production at mid-rapidity. Unpolarized cross section results are given for transverse momenta p_T=0.5 to 20 GeV/c, extending the range of published data to both lower and higher p_T. The cross section is described well for p_T < 1 GeV/c by an exponential in p_T, and, for p_T > 2 GeV/c, by perturbative QCD. Double helicity asymmetries A_LL are presented based on a factor of five improvement in uncertainties as compared to previously published results, due to both an improved beam polarization of 50%, and to higher integrated luminosity. These measurements are sensitive to the gluon polarization in the proton, and exclude maximal values for the gluon polarization.Comment: 375 authors, 7 pages, 3 figures. Submitted to Phys. Rev. D, Rapid Communications. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration

Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (p_T), elliptic flow, two-particle correlations, non-statistical fluctuations, and suppression of particle production at high p_T. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted to Nuclear Physics A as a regular article; v3 has minor changes in response to referee comments. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

System Size and Energy Dependence of Jet-Induced Hadron Pair Correlation Shapes in Cu+Cu and Au+Au Collisions at sqrt(s_NN) = 200 and 62.4 GeV

We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from {dijets} in Cu+Cu and Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from \Delta\phi=\pi in central and semi-central collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.Comment: 464 authors from 60 institutions, 6 pages, 3 figures, 2 tables. Submitted to Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm