277 research outputs found

    Micro Raman investigation of graphene synthesized by atmospheric pressure CVD on copper foil from decane

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    In this article we present the results of micro-Raman studies of graphene grown on copper foil surface by atmospheric pressure CVD using decane as precursor, nitrogen as carrier gas with zero flow of hydrogen. Analysis of Raman spectroscopy data showed that film contains spots with single layer thick graphene. We observed significant blue shift of 2D and G bands positions for mono-atomically thick graphene on copper foil. Following literature we relate this shift to the strain induced by the presence of copper substrate. Moreover, we observed changes in the defectiveness of graphene layers after the transfer, which was related to the appearance of chemically-induced defects and defects induced by changes in the mechanical strain

    Measurements of Ξ{\Xi }{^-} and Ξ+\overline{\Xi }{^+} production in proton–proton interactions at sNN\sqrt{s_{NN}}=17.3 GeV = 17.3 GeV in the NA61/SHINE experiment

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    International audienceThe production of Ξ(1321)\Xi (1321)^{-} and Ξ(1321)+\overline{\Xi }(1321)^{+} hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam momentum of 158 GeV ⁣/ ⁣c\hbox {Ge}\hbox {V}\!/\!c. Double differential distributions in rapidity y{y} and transverse momentum pTp_{T} are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both Ξ{\Xi }{^-} and Ξ+\overline{\Xi }{^+} . The rapidity and transverse momentum spectra are compared to transport model predictions. The Ξ{\Xi }{^-} mean multiplicity in inelastic p+p interactions at 158 GeV ⁣/ ⁣c\hbox {Ge}\hbox {V}\!/\!c is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair

    Measurements of Ξ(1530)0{\Xi \left( 1530\right) ^{0}} and Ξ(1530)0{\overline{\Xi }\left( 1530\right) ^{0}} production in proton–proton interactions at sNN\sqrt{s_{NN}} = 17.3  = 17.3  GeV \text{ GeV } in the NA61/SHINE experiment

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    Double-differential yields of Ξ(1530)0\Xi\left(1530\right)^{0} and Ξ(1530)0\overline{\Xi}\left(1530\right)^{0} resonances produced in \pp interactions were measured at a laboratory beam momentum of 158~\GeVc. This measurement is the first of its kind in \pp interactions below LHC energies. It was performed at the CERN SPS by the \NASixtyOne collaboration. Double-differential distributions in rapidity and transverse momentum were obtained from a sample of 26\cdot106^6 inelastic events. The spectra are extrapolated to full phase space resulting in mean multiplicity of Ξ(1530)0\Xi\left(1530\right)^{0} (6.73 ±\pm 0.25 ±\pm 0.67)×104\times10^{-4} and Ξ(1530)0\overline{\Xi}\left(1530\right)^{0} (2.71 ±\pm 0.18 ±\pm 0.18)×104\times10^{-4}. The rapidity and transverse momentum spectra and mean multiplicities were compared to predictions of string-hadronic and statistical model calculations

    Measurements of π±\pi ^\pm , K±K^\pm , p and pˉ\bar{p} spectra in 7^7Be+9^9Be collisions at beam momenta from 19A to 150A GeV ⁣/ ⁣c{\mathrm{Ge} \mathrm{V}}\!/\!c with the NA61/SHINE spectrometer at the CERN SPS

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    The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of π ± π± , K ± K± , p and p ¯ p¯ produced in the 20% most central 7 7 Be+ 9 9 Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150A GeV/c GeV/c . The energy dependence of the K ± K± /π ± π± ratios as well as of inverse slope parameters of the K ± K± transverse mass distributions are close to those found in inelastic p+p reactions. The new results are compared to the world data on p+p and Pb+Pb collisions as well as to predictions of the Epos, Urqmd, Ampt, Phsd and Smash models

    Two-particle correlations in azimuthal angle and pseudorapidity in central 7Be+9Be^7\hbox {Be}+{}^9\hbox {Be} collisions at the CERN Super Proton Synchrotron

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    Erratum to: Measurements of π±\pi ^\pm , K±K^\pm , p and pˉ\bar{p} spectra in 7^7Be+9^9Be collisions at beam momenta from 19A to 150A GeV/c with the NA61/SHINE spectrometer at the CERN SPS – NA61/SHINE Collaboration

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    Measurements of π\pi ^- production in 7^7Be + 9^9Be collisions at beam momenta from 19A to 150A GeV  ⁣/ ⁣cA\,\text{ GeV }\!/\!c in the NA61/SHINE experiment at the CERN SPS

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    The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of π±\pi ^\pm , K±K^\pm , p and pˉ\bar{p} produced in the 20% most central7^7Be+9^9Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150A GeV ⁣/ ⁣c{\mathrm{Ge} \mathrm{V}}\!/\!c. The energy dependence of the K±K^\pm /π±\pi ^\pm ratios as well as of inverse slope parameters of the K±K^\pm transverse mass distributions are close to those found in inelastic p+p reactions. The new results are compared to the world data on p+p and Pb+Pb collisions as well as to predictions of the Epos, Urqmd, Ampt, Phsd and Smash models

    Spectra and mean multiplicities of π\pi^{-} in central 40Ar+45Sc^{40}Ar+^{45} Sc collisions at 13A, 19A, 30A, 40A, 75A and 150A Ge V/c beam momenta measured by the NA61/SHINE spectrometer at the CERN SPS

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    International audienceThe physics goal of the strong interaction program of the NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) is to study the phase diagram of hadronic matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents differential inclusive spectra of transverse momentum, transverse mass and rapidity of π\pi ^{-} mesons produced in central40{}^{40}Ar+45{}^{45}Sc collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150A Ge  V  ⁣/ ⁣cA\,\text{ Ge }\text{ V }\!/\!\textit{c}. Energy and system size dependence of parameters of these distributions – mean transverse mass, the inverse slope parameter of transverse mass spectra, width of the rapidity distribution and mean multiplicity – are presented and discussed. Furthermore, the dependence of the ratio of the mean number of produced pions to the mean number of wounded nucleons on the collision energy was derived. The results are compared to predictions of several models

    Light (anti)nuclei production cross section studies in pp+C collisions at the NA61/SHINE experiment

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    NA61/SHINE is a large-acceptance fixed-target experiment located at the CERN SPS, which studies final hadronic states in interactions of various particles and nuclei. It is unique in terms of providing data on a variety of collision systems at different collision energies. This allows for wide deuteron, antiproton and antideuteron production cross-section studies. The latter are currently considered a possible dark matter interaction signal with exceptionally small background. The measurements on carbon target are important to reduce systematic experimental effects due to experiment-internal antideuteron production, as the most abundant element in the path of an incoming particle for the AMS-02 experiment is carbon. My talk will focus on analysis of NA61/SHINE data on pp+C thin target collisions in context of light (anti)nuclei production. I will present a preliminary analysis of experimental data and discuss quality cuts and the particle identification method as well as present deuteron and antideuteron yields
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