83 research outputs found

    Effect of nuclear transparency from the (p,2p) measurements on 6Li and 12C at 1 GeV

    Full text link
    We studied the production of protons to the backward direction in (p,2p) reactions on 6Li and 12C, accompanied by a proton emitted into the forward hemisphere. The momenta of the final two protons were measured in a wide range with the two-arm time-of-flight spectrometer. For each event we reconstructed the mass of the intermediate off-shell particles. We have discovered a strong narrow dip in the mass spectra of intermediate mesons at the mass of the real pion.Comment: 24 pages,11 figure

    Measurements of spin rotation parameter A in pion-proton elastic scattering at 1.62 GeV/c

    Get PDF
    The ITEP-PNPI collaboration presents the results of the measurements of the spin rotation parameter A in the elastic scattering of positive and negative pions on protons at P_beam = 1.62 GeV/c. The setup included a longitudinally-polarized proton target with superconductive magnet, multiwire spark chambers and a carbon polarimeter with thick filter. Results are compared to the predictions of partial wave analyses. The experiment was performed at the ITEP proton synchrotron, Moscow.Comment: 7 pages, 3 figures. To be published in Phys. Lett.

    Membranes with a boundary

    Full text link
    We investigate the recently developed theory of multiple membranes. In particular, we consider open membranes, i.e. the theory defined on a membrane world volume with a boundary. We first restrict our attention to the gauge sector of the theory. We obtain a boundary action from the Chern-Simons terms. Secondly, we consider the addition of certain boundary terms to various Chern-Simons theories coupled to matter. These terms ensure the full bulk plus boundary action has the correct amount of supersymmetry. For the ABJM model, this construction motivates the inclusion of a boundary quartic scalar potential. The boundary dynamics obtained from our modified theory produce Basu-Harvey type equations describing membranes ending on a fivebrane. The ultimate goal of this work is to throw light on the theory of fivebranes using the theory of open membranes.Comment: 48 pages, Latex, v2 references adde

    Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

    Get PDF
    Peer reviewe

    Measurement of the mass difference between top quark and antiquark in pp collisions at root s=8 TeV

    Get PDF
    Peer reviewe

    Measurement of prompt D0^{0} and D\overline{D}0^{0} meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at root SNN\sqrt{S_{NN}} = 5.02 TeV

    Get PDF
    The strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapiditydependent difference (Av2) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, v2) between D0 (uc) and D0 (uc) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of Av2. The rapidity-averaged value is found to be (Av2) = 0.001 ? 0.001 (stat)? 0.003 (syst) in PbPb collisions at ?sNN = 5.02 TeV. In addition, the influence of the collision geometry is explored by measuring the D0 and D0mesons v2 and triangular flow coefficient (v3) as functions of rapidity, transverse momentum (pT), and event centrality (a measure of the overlap of the two Pb nuclei). A clear centrality dependence of prompt D0 meson v2 values is observed, while the v3 is largely independent of centrality. These trends are consistent with expectations of flow driven by the initial-state geometry. ? 2021 The Author. Published by Elsevier B.V. This is an open access article under the CC BY licens

    Measurements of t(t)over-bar charge asymmetry using dilepton final states in pp collisions at root s=8 TeV

    Get PDF
    Peer reviewe

    Search for lepton flavour violating decays of heavy resonances and quantum black holes to an eμ pair in proton–proton collisions at √s = 8 TeV

    Get PDF
    A search for narrow resonances decaying to an electron and a muon is presented. The eμ mass spectrum is also investigated for non-resonant contributions from the production of quantum black holes (QBHs). The analysis is performed using data corresponding to an integrated luminosity of 19.7 fb-1 collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. With no evidence for physics beyond the standard model in the invariant mass spectrum of selected eμ pairs, upper limits are set at 95 % confidence level on the product of cross section and branching fraction for signals arising in theories with charged lepton flavour violation. In the search for narrow resonances, the resonant production of τ sneutrino in R-parity violating supersymmetry is considered. The τ sneutrino is excluded for masses below 1.28 TeV for couplings λ132= λ231= λ311′= 0.01 , and below 2.30 TeV for λ132= λ231= 0.07 and λ311′= 0.11. These are the most stringent limits to date from direct searches at high-energy colliders. In addition, the resonance searches are interpreted in terms of a model with heavy partners of the Z boson and the photon. In a framework of TeV-scale quantum gravity based on a renormalization of Newton’s constant, the search for non-resonant contributions to the eμ mass spectrum excludes QBH production below a threshold mass Mth of 1.99 TeV. In models that invoke extra dimensions, the bounds range from 2.36 TeV for one extra dimension to 3.63 TeV for six extra dimensions. This is the first search for QBHs decaying into the eμ final state

    Measurement of the differential cross section for top quark pair production in pp collisions at √s=8 TeV

    Get PDF
    The normalized differential cross section for top quark pair (tt¯) production is measured in pp collisions at a centre-of-mass energy of 8TeV at the CERN LHC using the CMS detector in data corresponding to an integrated luminosity of 19.7fb-1. The measurements are performed in the lepton+jets (e/μ++jets) and in the dilepton e+e-, μ+μ-, and e±μ∓) decay channels. The tt¯ cross section is measured as a function of the kinematic properties of the charged leptons, the jets associated to b quarks, the top quarks, and the tt¯ system. The data are compared with several predictions from perturbative quantum chromodynamic up to approximate next-to-next-to-leading-order precision. No significant deviations are observed relative to the standard model predictions. © 2015, CERN for the benefit of the CMS collaboration
    corecore