18 research outputs found
Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs
We present a determination of the gluon polarization Delta G/G in the
nucleon, based on the helicity asymmetry of quasi-real photoproduction events,
Q^2<1(GeV/c)^2, with a pair of large transverse-momentum hadrons in the final
state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV
polarized muon beam scattered on a polarized 6-LiD target. The helicity
asymmetry for the selected events is = 0.002 +- 0.019(stat.) +-
0.003(syst.). From this value, we obtain in a leading-order QCD analysis Delta
G/G=0.024 +- 0.089(stat.) +- 0.057(syst.) at x_g = 0.095 and mu^2 =~ 3
(GeV}/c)^2.Comment: 10 pages, 3 figure
Measurement of the Spin Structure of the Deuteron in the DIS Region
We present a new measurement of the longitudinal spin asymmetry A_1^d and the
spin-dependent structure function g_1^d of the deuteron in the range 1 GeV^2 <
Q^2 < 100 GeV^2 and 0.004< x <0.7. The data were obtained by the COMPASS
experiment at CERN using a 160 GeV polarised muon beam and a large polarised
6-LiD target. The results are in agreement with those from previous experiments
and improve considerably the statistical accuracy in the region 0.004 < x <
0.03.Comment: 10 pages, 6 figures, subm. to PLB, revised: author list, Fig. 4,
details adde
Search for the Phi(1860) Pentaquark at COMPASS
Narrow Xi-pi+- and Xi-bar+pi+- resonances produced by quasi-real photons have
been searched for by the COMPASS experiment at CERN. The study was stimulated
by the recent observation of an exotic baryonic state decaying into Xi-pi-, at
a mass of 1862 MeV, interpreted as a pentaquark. While the ordinary hyperon
states Xi(1530)^0 and Xi-bar(1530)^0 are clearly seen, no exotic baryon is
observed in the data taken in 2002 and 2003.Comment: 10 pages, 5 figure
Analysis of parameters for a computer system for electrical impulses of the human body control.
A facilities and various types of nerve impulse reading systems are considered. Various methods of reading nerve impulses are analyzed, their advantages and disadvantages are highlighted. The future directions of developing and research are pointed.Рассмотрены особенности и различные типы систем считывания нервных импульсов. Проанализированы методы считывания нервных импульсов, выделены их преимущества и недостатки. Намечены направления дальнейшей разработки и исследований
New vector/scalar Overhauser DNP magnetometers POS-4 for magnetic observatories and directional oil drilling support
This paper covers same results of the research directed at developing an absolute vector proton magnetometer POS-4 based on the switching bias magnetic fields methods. Due to the high absolute precision and stability magnetometer POS-4 found application not only for observatories and to directional drilling support of oi and gas well. Also we discuss the some basic errors of measurements and discuss the long-term experience in the testing of magnetic observatories ART and PARATUNKA
Comparative Study of Methanogenic Pathways in the Sediments of Thermokarst and Polygenetic Yamal Lakes
Comparative study of methanogen diversity and potential activity of different methanogenic pathways in the sediments of young thermokarst and mature polygenetic Yamal lakes was carried out. The hydrogenotrophic pathway of methanogenesis played an important role in methane formation in thermokarst lakes. The acetoclastic and methylotrophic pathways were also revealed there. In a polygenetic lake with a dissolved organic matter content closest to that of the thermokarst lakes, methanogenesis proceeded more intensively, and the relative abundance of methanogens, especially acetoclastic ones, was higher than in thermokarst lakes. The activity of methyl-reducing methanogens was also assumed there. Methanogens of the genera Methanothrix and Methanoregula, as well as representatives of the family Methanomassiliicoccaceae were identified in the sediments of all lakes. Methane-oxidizing bacteria (Methylobacter, Candidatus "Methylomirabilis") and archaea (Ca. "Methanoperedens") were also detected