Charm production nearby threshold in pA-interactions at 70 GeV

The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70 GeV proton beam with C, Si and Pb targets were studied to detect decays of charmed $D^0$, $\overline D^0$, $D^+$, $D^-$ mesons and $\Lambda _c^+$ baryon near their production threshold. Measurements of lifetimes and masses are shown a good agreement with PDG data. The inclusive cross sections of charm production and their A-dependencies were obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measured cross section of the total open charm production ($\sigma _{\mathrm {tot}}(c\overline c)$ = 7.1 $\pm$ 2.3(stat) $\pm$1.4(syst) $\mu$b/nucleon) at the collision c.m. energy $\sqrt {s}$ = 11.8 GeV is well above the QCD model predictions. The contributions of different species of charmed particles to the total cross section of the open charm production in proton-nucleus interactions vary with energy.Comment: 4 pages, 6 pages, 38th International Conference on High Energy Physics 3-10 August 2016, Chicago, US

Исследование фазовых равновесий тройной системы Zn—Se—Fe для лазерных технологий

The problem of obtaining crystalline ZnSe doped with d-elements for obtaining high-efficiency laser materials with characteristics in a wide IR range don’t possible successfully solved without reliable data on phase equilibrium and solubility of the components entering the system. The theoretical and experimental analysis of the three-component Zn—Se—Fe system for obtaining new fundamental information on phase using X-ray analysis (XRD) and inductively coupled plasma mass spectrometry (ICP-MS) was carried out. New experimental data of isothermal annealing in the ternary Zn—Se—Fe system at the temperatures 730 K (I, II), 814 K (III, IV), 1073 K (V), as well as information on Fe solubility in bi- and monovariant conditions by X-ray studies have shown the existence of the coexistence of the following phases: Fe3Zn10-Fe11Zn40-Zn-ZnSe (I), ZnSe-FeSe2-Fe7Se8 (II), ZnSe-Fe3Zn10-Fe (III), FeSe2-Fe7Se8-Se (IV), ZnSe-FeSe- Fe3Se4 (V), ZnSe-FeSe (VI) and confirmed the reliability of theoretical isothermal sections.Проведен теоретический и экспериментальный анализ фазовых равновесий в тройной системе Zn—Se—Fe с применением рентгенофазового анализа и масс-спектрометрии с индуктивно связанной плазмой. Получены данные о моновариантных равновесиях в изотермических сечениях при температуре 730, 814 и 1073 К, а также сведения о растворимости железа в условиях би- и моновариантных равновесий при 1073 К. Определен фазовый состав образцов системы Zn—Se—Fe, синтезированных при различных температурах и разном валовом составе. Подтверждена достоверность теоретически построенных изотермических сечений Т—Х—Y-проекции P—T— Х—Y-диаграммы тройной системы Zn—Se—Fe

Interferometry of Direct Photons in Central 280Pb+208Pb Collisions at 158A GeV

Two-particle correlations of direct photons were measured in central 208Pb+208Pb collisions at 158 AGeV. The invariant interferometric radii were extracted for 100<K_T<300 MeV/c and compared to radii extracted from charged pion correlations. The yield of soft direct photons, K_T<300 MeV/c, was extracted from the correlation strength and compared to theoretical calculations.Comment: 5 pages, 4 figure

Multiplicity Distributions and Charged-neutral Fluctuations

Results from the multiplicity distributions of inclusive photons and charged particles, scaling of particle multiplicities, event-by-event multiplicity fluctuations, and charged-neutral fluctuations in 158$\cdot A$ GeV Pb+Pb collisions are presented and discussed. A scaling of charged particle multiplicity as $N_{part}^{1.07\pm 0.05}$ and photons as $N_{part}^{1.12\pm 0.03}$ have been observed, indicating violation of naive wounded nucleon model. The analysis of localized charged-neutral fluctuation indicates a model-independent demonstration of non-statistical fluctuations in both charged particles and photons in limited azimuthal regions. However, no correlated charged-neutral fluctuations are observed.Comment: Talk given at the International Symposium on Nuclear Physics (ISNP-2000), Mumbai, India, 18-22 Dec 2000, Proceedings to be published in Pramana, Journal of Physic

Clinical and laboratory evaluation of workers metallurgical production dental diseases prevention effectiveness

Показано, что проведение комплексной профилактики стоматологических заболеваний у работников металлургического производства снижает величину колебаний pH ротовой жидкости в отдельных пробах в 2 раза, нормализует процент подвижных ядер буккального эпителия (53 %) и отношение амплитуд колебаний плазмолем и ядер (Апл/Ая 1,79). Кроме того, спектроколориметрически показано, что при этом улучшаются функциональные реакции микрокапиллярного русла на жевательную нагрузку и улучшается барьерная защита десен (снижается проницаемость для красителя раствора Шиллера-Писарева).Показано, що проведення комплексної профілактики стоматологічних захворювань у працівників металургійного виробництва знижує величину коливань pH ротової рідини в окремих пробах в 2 рази, нормалізує відсоток рухливих ядер буккального епітелію (53 %) і відношення амплітуд коливань плазмолем і ядер (Апл/Ая 1,79). Крім того, спектроколориметрично показано, що при цьому покращуються функціональні реакції мікрокапілярного русла на жувальне навантаження і бар'єрний захист ясен (знижується проникність їх для фарбника розчину Шилера-Писарєва).Metallurgical industry occupies a leading position by level of occupational morbidity of workers, which requires the development of effective comprehensive prevention programs, including dental diseases. The aim of the work was to evaluate the influence of the developed complex prevention of major dental diseases metallurgical industry workers on the biophysical parameters of oral liquid, microcapillary bed gums and inflammatory processes in it. Materials and methods. Workers of metallurgical plant (29 persons), in addition to basic therapy, received several times a year, specially designed preventive complex. Was evaluated parameters of oral liquid, buccal epithelium cells, microcapillary bed gums and inflammation in it. Results. Conclusions. Conducted integrated prevention of stomatological diseases among workers of metallurgical production reduces the value in oral liquid of pH oscillations in individual samples in 2 times, normalizes the percentage of mobile nuclei of buccal epithelium (53%) and the ratio of the amplitudes of oscillations plazmolem and nuclei (Apl / An 1.79) improves functional microcapillary reaction of gum to chewing load and barrier protection

Scaling of Particle and Transverse Energy Production in 208Pb+208Pb collisions at 158 A GeV

Transverse energy, charged particle pseudorapidity distributions and photon transverse momentum spectra have been studied as a function of the number of participants (N_{part}) and the number of binary nucleon-nucleon collisions (N_{coll}) in 158 A GeV Pb+Pb collisions over a wide impact parameter range. A scaling of the transverse energy pseudorapidity density at midrapidity as N_{part}^{1.08 \pm 0.06} and N_{coll}^{0.83 \pm 0.05} is observed. For the charged particle pseudorapidity density at midrapidity we find a scaling as N_{part}^{1.07 \pm 0.04} and N_{coll}^{0.82 \pm 0.03}. This faster than linear scaling with N_{part} indicates a violation of the naive Wounded Nucleon Model.Comment: 13 pages, 16 figures, submitted to European Physical Journal C (revised results for scaling exponents

Event-by-Event Fluctuations in Particle Multiplicities and Transverse Energy Produced in 158.A GeV Pb+Pb collisions

Event-by-event fluctuations in the multiplicities of charged particles and photons, and the total transverse energy in 158$\cdot A$ GeV Pb+Pb collisions are studied for a wide range of centralities. For narrow centrality bins the multiplicity and transverse energy distributions are found to be near perfect Gaussians. The effect of detector acceptance on the multiplicity fluctuations has been studied and demonstrated to follow statistical considerations. The centrality dependence of the charged particle multiplicity fluctuations in the measured data has been found to agree reasonably well with those obtained from a participant model. However for photons the multiplicity fluctuations has been found to be lower compared to those obtained from a participant model. The multiplicity and transverse energy fluctuations have also been compared to those obtained from the VENUS event generator.Comment: To appear in Physical Review C; changes : more detailed discussion on errors and few figures modifie

Systematics of Inclusive Photon Production in 158 AGeV Pb Induced Reactions on Ni, Nb, and Pb Targets

The multiplicity of inclusive photons has been measured on an event-by-event basis for 158 AGeV Pb induced reactions on Ni, Nb, and Pb targets. The systematics of the pseudorapidity densities at midrapidity (rho_max) and the width of the pseudorapidity distributions have been studied for varying centralities for these collisions. A power law fit to the photon yield as a function of the number of participating nucleons gives a value of 1.13+-0.03 for the exponent. The mean transverse momentum, , of photons determined from the ratio of the measured electromagnetic transverse energy and photon multiplicity, remains almost constant with increasing rho_max. Results are compared with model predictions.Comment: 16 pages including 4 figure

Centrality Dependence of Neutral Pion Production in 158 A GeV Pb + Pb Collisions

The production of neutral pions in 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied for the range 0.3 GeV/c < mT-m0 < 4.0 GeV/c. The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons which is most naturally explained by assuming an equilibrated system.Comment: 5 pages, Latex, including 3 eps figures, submitted to Phys.Rev.Lett; updated pQCD comparison due to new input from the author, updated references, corrected plotting error in figure