Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at √s=7 TeV

Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at root s = 7 TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dN(ch)/d eta vertical bar(vertical bar eta vertical bar<0.5) = 5.78 +/- 0.01(stat) +/- 0.23(stat) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from root s = 0.9 to 7 TeV is [66.1 +/- 1.0(stat) +/- 4.2(syst)]%. The mean transverse momentum is measured to be 0.545 +/- 0.005(stat) +/- 0.015(syst) GeV/c. The results are compared with similar measurements at lower energies

Search for Charged Higgs Bosons in Decays of Top Quarks in pp Collisions at s=1.96 TeV

We report on the first direct search for charged Higgs bosons decaying into cs in tt events produced by pp collisions at s=1.96 TeV. The search uses a data sample corresponding to an integrated luminosity of 2.2 fb(-1) collected by the CDF II detector at Fermilab and looks for a resonance in the invariant mass distribution of two jets in the lepton+jets sample of tt candidates. We observe no evidence of charged Higgs bosons in top quark decays. Hence, 95% upper limits on the top quark decay branching ratio are placed at B(t -> H(+)b) cs)=1.0. The upper limits on B(t -> H(+)b) are also used as model-independent limits on the decay branching ratio of top quarks to generic scalar charged bosons beyond the standard model.We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A.P. Sloan Foundation; the Bundesministerium für Bildung und Forschung, Germany; the Korean Science and Engineering Foundation and the Korean Research Foundation; the Science and Technology Facilities Council and the Royal Society, UK; the Institut National de Physique Nucleaire et Physique des Particules/CNRS; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovación, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; and the Academy of Finland.Peer reviewe

Mode de glissement des dislocations (010)[001] dans les feldspaths alcalins. methr et modélisation.

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Growth and structural analysis of diluted magnetic oxide Co-doped CeO2−δ films deposited on Si and SrTiO3 (1 0 0)

International audienceFor this study, Co-doped CeO2−δ thin films were grown on silicon and SrTiO3 substrates by pulsed laser deposition. Their structure was analyzed using X-ray diffraction and transmission electron microscopy. On native silicon wafer, the films are textured. The preferential orientation is CeO2 (1 0 0) for a growth under oxygen ambient (0.05 mbar) and CeO2 (1 1 1) for a growth under vacuum (10−6 mbar). When a buffer layer of CeO2 is previously deposited under oxygen ambient, the films adopt the CeO2 (1 0 0) preferential orientation, even if subsequent growth is carried out under vacuum. On SrTiO3 (1 0 0), the films are epitaxied under oxygen ambient or under vacuum with an oxygen-grown CeO2 buffer layer. In epitaxial films grown under vacuum, increasing contents of Co atoms (below 7%) induce an expansion of the CeO2 unit cell and a decrease of crystalline order. The relationship between the structural order and the magnetic behaviour, in particular the magnetic anisotropy, is discussed. The present study suggests that the ferromagnetic behaviour is not related to grain boundaries and that the epitaxy strains are not responsible for the magnetic anisotropy. This strongly supports a ferromagnetism related to point defects (oxygen vacancies) in Co-doped CeO2−δ films

Study of ZnO crystals and Zn1−xMxO (M=Co, Mn) epilayers grown by pulsed laser deposition on Click to view the MathML source substrate.

Crystal defects in Seeded Chemical Vapour Transport (SCVT) and hydrothermal ZnO substrates were characterised mainly by X-ray topography and diffraction. Zn1−xMxO (M=Co, Mn) epilayers were grown on hydrothermal ZnO(OO.1) substrate by Pulsed Laser Deposition (PLD). It is shown that the epitaxy strains are partially relaxed through dislocations in the 10.0 glide planes. The crystal perfection of the epilayers was analysed by high-resolution X-ray diffraction. Almost intrinsic rocking curves were observed for Zn1−xCoxO epilayers and the c-axis parameter increases proportionally with the Co content. This suggests that Co atoms are well located at substitutional sites in the ZnO matrix. A larger distortion of the ZnO matrix is induced by the insertion of Mn atoms. A paramagnetic behaviour was observed in Zn1−xCoxO epilayers with a low proportion of active Co atoms. A weak ferromagnetic behaviour was observed only for Zn1−xCoxO epilayers when a few Al atoms (1.6%) were incorporated

Electron paramagnetic resonance study of Zn1–xCoxO: A predicted high-temperature ferromagnetic semiconductor.

International audienceThe magnetic properties of Co2+ ions in epitaxial (Zn,Co)O layers with 10% Co concentration have been studied by electron paramagnetic resonance spectroscopy. The Co-related EPR spectrum is characterized by a 200-G broad anisotropic single line with g factors close to those of the isolated Co2+ ion. The temperature dependence of the EPR signal follows a Curie-Weiss law with a critical temperature of +12 K. We find no evidence for a high-temperature ferromagnetic state. Magnetocrystalline anisotropy is observed and a canted spin arrangement is suggested

Kinetics of Si capping process of Ge/Si(0 0 1) quantum dots.

The overgrowth of Si on Ge/Si(0 0 1) islands in a UHV chemical-vapor deposition system is investigated by reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), transmission electronic microscopy (TEM), and photoluminescence. It has been shown that the capping process comprises three stages, firstly a shape transition from dome to pyramid induced by strain relaxation due to interdiffusion, followed by a pyramid–dome shape transition, before the smoothening of the surface. This study shows the existence of a strong surface roughness even if the Si cap thickness is higher than the island height. The roughness is then a parameter that should be considered in a multilayer system to explain the mechanism of vertical alignment

Four Three-dimensionnal Lanthanide Coordination Polymers Constructed from Benzene-1,4-dioxyacetic acid.

WOSInternational audienceFour crystalline lanthanide(III) three-dimensional (3D) coordination polymers {[La(BDOA)1.5(H2O)]?H2O}n (1), {[Nd(BDOA)1.5(H2O)]?H2O}n (2), [Tm(BDOA)1.5(H 2O)]n (3) , [Yb(BDOA)1.5(H2O)]n (4) were obtained under hydrothermal conditions and characterized by elemental analysis, IR, as well as single-crystal X-ray diffraction. Compounds 1-2 crystallize in the monoclinic system, space group P21/c, they are isostructural and exhibit the same 321.457.513 topological network constructed from different coordination modes of two BDOA ligands, whereas isostructural 3 and 4 crystallizes in the triclinic system, space group P-1, it holds 39.420.57 topological architecture based on another two different coordination modes BDOA ligands. Moreover, a computational method is applied to evaluate the potential porosity of complex 1

Scanning transmission ion microscopy computed tomography (STIM-CT) for inertial confinement fusion (ICF) targets

ICF target quality control in the laser fusion program is vital to ensure that the energy deposition from the lasers results in uniform compression and minimization of Rayleigh-Taylor instabilities, which requires surface finishes on the order of submicron-scale. During target fabrication process the surface finish and the dimensions of the hohlraum need be well controlled. Density variations and nonspherical or nonconcentric shells might be produced. Scanning transmission ion microscopy computed tomography (STIM-CT) is able to reconstruct the three-dimensional quantitative structure of ICF targets a few tens of micrometers in size. Compared to other types of probe techniques, the main advantage of STIM-CT is that quantitative information about mass density and sphericity can be obtained directly and non-destructively, utilizing specific reconstruction codes. We present a case of ICF target (composed of polyvinyl alcohol) characterization by STIM-CT in order to demonstrate the STIM-CT potential impact in assessing target fabrication processes