4,956 research outputs found

    Test beam Characterizations of 3D Silicon Pixel detectors

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    3D silicon detectors are characterized by cylindrical electrodes perpendicular to the surface and penetrating into the bulk material in contrast to standard Si detectors with planar electrodes on its top and bottom. This geometry renders them particularly interesting to be used in environments where standard silicon detectors have limitations, such as for example the radiation environment expected in an LHC upgrade. For the first time, several 3D sensors were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip and readout electronics. Devices with different electrode configurations have been characterized in a 100 GeV pion beam at the CERN SPS. Here we report results on unirradiated devices with three 3D electrodes per 50 x 400 um2 pixel area. Full charge collection is obtained already with comparatively low bias voltages around 10 V. Spatial resolution with binary readout is obtained as expected from the cell dimensions. Efficiencies of 95.9% +- 0.1 % for tracks parallel to the electrodes and of 99.9% +- 0.1 % at 15 degrees are measured. The homogeneity of the efficiency over the pixel area and charge sharing are characterized.Comment: 5 pages, 7 figure

    Nuclear Antishadowing in Neutrino Deep Inelastic Scattering

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    The shadowing and antishadowing of nuclear structure functions in the Gribov-Glauber picture is due respectively to the destructive and constructive interference of amplitudes arising from the multiple-scattering of quarks in the nucleus. The effective quark-nucleon scattering amplitude includes Pomeron and Odderon contributions from multi-gluon exchange as well as Reggeon quark-exchange contributions. We show that the coherence of these multiscattering nuclear processes leads to shadowing and antishadowing of the electromagnetic nuclear structure functions in agreement with measurements. This picture leads to substantially different antishadowing for charged and neutral current reactions, thus affecting the extraction of the weak-mixing angle θW\theta_W. We find that part of the anomalous NuTeV result for θW\theta_W could be due to the nonuniversality of nuclear antishadowing for charged and neutral currents. Detailed measurements of the nuclear dependence of individual quark structure functions are thus needed to establish the distinctive phenomenology of shadowing and antishadowing and to make the NuTeV results definitive.Comment: 38 pages, 15 figure

    IBK UNIVERSITAS COKROAMINOTO PALOPO

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    Tujuan Iptek bagi Kewiausahaan (IbK) di Universitas Cokroaminoto Palopo secara Umum adalah penguatan kapasitas dan kapabilitas kewirausahaan mahasiswa dan alumni untuk menjadi job creator secara umum di Universitas Cokroaminoto Palopo (UNCP). Secara khusus target yang ingin dicapai dalam program IbK di Universitas Cokroaminoto Palopo adalah; 1) Adanya pengembangan dan pengingkatan pengetahuan keterampilan tenant dalam membuka binsis (berwirausaha), 2) Menciptakan 5 wirausaha baru di UNCP yang mandiri dan berdaya saing berbasis Potensi lokal dan Ipteks setiap tahunnya, 3) Terciptanya Wira Usaha baru yang berbasis Potensi lokal dan Ipteks setiap tahunnya, 4) Merancang dan menciptakan model pelatihan kewirausahaan yang disesuaikan dengan kebutuhan tenant, 5) Mempublikasikan laporan program setiap tahunnya melaui seminar dan junral yang bereputasi secara nasional maupun internasioanl. Luaran dari program IbK ini adalah; a) Luaran pada tahun pertama program IbK ini adalah publikasi pada jurnal nasional dan seminar nasional, b) Tahun pertama program IbK di Universitas Cokroaminoto Palopo wajib menghasilkan minimal 5 wirausaha baru yang berbasis Potensi lokal dan Ipteks setiapa tahunnya, c) pada tahun pertama, kedua dan ketiga menghasilkan peserta IbK yang menjadi wirausaha mandiri mengalami peningkatan di tahun ketiga sebesar 80%. d) Mengasilkan minimal 2 produk atau jasa Wira Usaha baru (WUB) yang berbasis Potensi lokal dan Ipteks, e) Ke 5 tenant setiap tahunnya mampu membangun jejaring wirausaha yang lebih luas dan mampu merekrut tenaga kerja. Metode pendekatan yang dilakukan yaitu pelatihan kewirausahaan, magang, pendampingan dan monitoring-evaluasi Program IbK di UNCP dirancang setiap tahunnya membina minimal 20 tenant dan ditargetkan menghasilkan 5 wirausaha baru yang mandiri setiap tahunnya. Tenan tersebut berasal dari PKM kewirausahaan dan program wirausaha lainnya. Untuk mempertahankan eksistensi capaian setiap tahunnya dengan jumlah 20 tenant, maka pengelolah IbK di Universitas Cokroaminoto Palopo akan merekrut tenan baru dari sejumlah tenant yang telah berwirausha agar tenat tetap konsisten 20 setiap tahunny a. Pada prinsipnya program IbK di Universitas Cokroaminoto Palopo sehingga setiap mahasiswa dan alumni yang menjalankan wirausha atau mempunyai jiwa kewiraushaan dapat mendaftar sebagai anggota tenant tanpa dibatasi di sekertariat IbK di Universitas Cokroaminoto Palopo. Setiap mahsiswab yang mendaftar dan memenuhi criteria di program IbK Universitas Cokroaminoto Palopo akan difasilitasi untuk berpartisipasi dalam program yang telah dirancang secara professional oleh pengelolah IbK di Universitas Cokroaminoto Palopo. Kata Kunci: Tenan, UNCP dan Wirausaha Mandiri

    Combined QCD and electroweak analysis of HERA data

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    A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarisation of the electron beam was taken into account for the ZEUS data recorded between 2004 and 2007. Results on the vector and axial-vector couplings of the Z boson to u- and d-type quarks, on the value of the electroweak mixing angle and the mass of the W boson are presented. The values obtained for the electroweak parameters are in agreement with Standard Model predictions.Comment: 32 pages, 10 figures, accepted by Phys. Rev. D. Small corrections from proofing process and small change to Fig. 12 and Table

    Limits on the effective quark radius from inclusive epep scattering at HERA

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    The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current epep scattering corresponding to a luminosity of around 1 fb1^{-1} have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive epep data is presented; simultaneous fits of parton distribution functions together with contributions of "new physics" processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is 0.4310160.43\cdot 10^{-16} cm.Comment: 10 pages, 4 figures, accepted by Phys. Lett.

    Measurement of the cross-section ratio sigma_{psi(2S)}/sigma_{J/psi(1S)} in deep inelastic exclusive ep scattering at HERA

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    The exclusive deep inelastic electroproduction of ψ(2S)\psi(2S) and J/ψ(1S)J/\psi(1S) at an epep centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range 2<Q2<802 < Q^2 < 80 GeV2^2, 30<W<21030 < W < 210 GeV and t<1|t| < 1 GeV2^2, where Q2Q^2 is the photon virtuality, WW is the photon-proton centre-of-mass energy and tt is the squared four-momentum transfer at the proton vertex. The data for 2<Q2<52 < Q^2 < 5 GeV2^2 were taken in the HERA I running period and correspond to an integrated luminosity of 114 pb1^{-1}. The data for 5<Q2<805 < Q^2 < 80 GeV2^2 are from both HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb1^{-1}. The decay modes analysed were μ+μ\mu^+\mu^- and J/ψ(1S)π+πJ/\psi(1S) \,\pi^+\pi^- for the ψ(2S)\psi(2S) and μ+μ\mu^+\mu^- for the J/ψ(1S)J/\psi(1S). The cross-section ratio σψ(2S)/σJ/ψ(1S)\sigma_{\psi(2S)}/\sigma_{J/\psi(1S)} has been measured as a function of Q2,WQ^2, W and tt. The results are compared to predictions of QCD-inspired models of exclusive vector-meson production.Comment: 24 pages, 8 figure

    An NLO QCD analysis of inclusive cross-section and jet-production data from the ZEUS experiment

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    The ZEUS inclusive differential cross-section data from HERA, for charged and neutral current processes taken with e+ and e- beams, together with differential cross-section data on inclusive jet production in e+ p scattering and dijet production in \gamma p scattering, have been used in a new NLO QCD analysis to extract the parton distribution functions of the proton. The input of jet data constrains the gluon and allows an accurate extraction of \alpha_s(M_Z) at NLO; \alpha_s(M_Z) = 0.1183 \pm 0.0028(exp.) \pm 0.0008(model) An additional uncertainty from the choice of scales is estimated as \pm 0.005. This is the first extraction of \alpha_s(M_Z) from HERA data alone.Comment: 37 pages, 14 figures, to be submitted to EPJC. PDFs available at http://durpdg.dur.ac.uk/hepdata in LHAPDFv

    Measurement of neutral current e+/-p cross sections at high Bjorken x with the ZEUS detector

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    The neutral current e+/-p cross section has been measured up to values of Bjorken x of approximately 1 with the ZEUS detector at HERA using an integrated luminosity of 187 inv. pb of e-p and 142 inv. pb of e+p collisions at sqrt(s) = 318GeV. Differential cross sections in x and Q2, the exchanged boson virtuality, are presented for Q2 geq 725GeV2. An improved reconstruction method and greatly increased amount of data allows a finer binning in the high-x region of the neutral current cross section and leads to a measurement with much improved precision compared to a similar earlier analysis. The measurements are compared to Standard Model expectations based on a variety of recent parton distribution functions.Comment: 39 pages, 9 figure
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