38 research outputs found

    Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR

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    The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the annihilation of pˉ+p\bar p +p into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction pˉ+pe++e\bar p +p \to e^++ e^- can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of q214q^2\simeq 14 (GeV/c)2^2. The total pˉ+pe++e\bar p +p\to e^++e^- cross section will be measured up to q228q^2\simeq 28 (GeV/c)2^2. The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.Comment: 12 pages, 4 tables, 8 figures Revised, added details on simulations, 4 tables, 9 figure

    Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

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    Simulation results for future measurements of electromagnetic proton form factors at \PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel pˉpe+e\bar p p \to e^+ e^- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.\textit{i.e.} pˉpπ+π\bar p p \to \pi^+ \pi^-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance

    Current etiological structure of bacteremia at the intensive care units of Yekaterinburg

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    In this report we present the results of bacteriological analysis of blood samples taken from patients at the intensive care units of Yekaterinburg city hospitals in 2006 - 2010. Studies were done in “BACTEC” (Beckton Dickinson) and “Walk/Away'1 (Siemens Healthcare) bacteriological automated systems. Highly resistant to antibiotics nosocomial strains of S. aureus (50.44%), Enterococcus spp. (19.77%), coagulase negative Staphilococcus spp. (9.25%), K. pneumoniae (7.98%), A baumannii (7.22%), E.coli (4.69%), P. Aerugionosa (3.8%) were isolated from adult patients with sepsis. Vancomycin and Unezolid remain highly active against Staphilococcus spp. and Enterococcus spp. (100% of strains were sensitive). Carbapenems are still actual for the therapy of septic conditions caused by representatives of Enterobacteriaceae family (more than 99% of strains were sensitive). Isolates of P. aeruginosa and A. baumannii arise certain difficulties for the adequate choice of drugs because their sensitivity to antibiotics needs to be determined.В работе представлены результаты микробиологического исследования крови 4133 пациентов ОРИТ стационаров г. Екатеринбурга за 2006-201 Ог.г. Работа выполнена с использованием микробиологических анализаторов Bactec (Becton Dickinson, США) и Walk Away (Siemens,USA). Среди возбудителей сепсиса у взрослых пациентов преобладают штаммы высокорезистентной госпитальной флоры S. aureus (50,44%), Enterococcus spp. (19,77%), коагулазоотрицательные стафилококки (9,25%), К. pneumoniae (7,98%), A. baumannii (7,22%), E.coli (4,69%), P. aeruginosa (3,8%). Ванкомицин и линезолид сохраняют высокую антибактериальную активность в отношении стафилококков и энтерококков (100% чувствительных штаммов). Карбапенемы продолжают оставаться препаратами выбора при терапии сепсиса, вызванного энтеробактериями (более 99% чувствительных штаммов). Наибольшую сложность для клинициста представляют случаи выделения P. aeruginosa, A. baumannii, при которых для подбора адекватной терапии требуется определение антибиотикочувствительности

    Technical Design Report for the PANDA Solenoid and Dipole Spectrometer Magnets

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    This document is the Technical Design Report covering the two large spectrometer magnets of the PANDA detector set-up. It shows the conceptual design of the magnets and their anticipated performance. It precedes the tender and procurement of the magnets and, hence, is subject to possible modifications arising during this process.Comment: 10 pages, 14MB, accepted by FAIR STI in May 2009, editors: Inti Lehmann (chair), Andrea Bersani, Yuri Lobanov, Jost Luehning, Jerzy Smyrski, Technical Coordiantor: Lars Schmitt, Bernd Lewandowski (deputy), Spokespersons: Ulrich Wiedner, Paola Gianotti (deputy

    First Measurement of Chiral Dynamics in \pi^- \gamma -> \pi^- \pi^- \pi^+

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    The COMPASS collaboration at CERN has investigated the \pi^- \gamma -> \pi^- \pi^- \pi^+ reaction at center-of-momentum energy below five pion masses, sqrt(s) < 5 m(\pi), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t' < 0.001 (GeV/c)^2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3\pi-invariant mass m(3\pi) = sqrt(s) were extracted. The absolute cross section was determined in seven bins of s\sqrt{s} with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.Comment: 10 pages, 5 figure

    Measurement of the Longitudinal Spin Transfer to Lambda and Anti-Lambda Hyperons in Polarised Muon DIS

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    The longitudinal polarisation transfer from muons to lambda and anti-lambda hyperons, D_LL, has been studied in deep inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to lambda and anti-lambda produced in the current fragmentation region exhibit different behaviours as a function of x and xF . The measured x and xF dependences of D^lambda_LL are compatible with zero, while D^anti-lambda_LL tends to increase with xF, reaching values of 0.4 - 0.5. The resulting average values are D^lambda_LL = -0.012 +- 0.047 +- 0.024 and D^anti-lambda_LL = 0.249 +- 0.056 +- 0.049. These results are discussed in the frame of recent model calculations.Comment: 13 pages, 7 figure

    Azimuthal asymmetries of charged hadrons produced by high-energy muons scattered off longitudinally polarised deuterons

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    Azimuthal asymmetries in semi-inclusive production of positive (h^+) and negative hadrons (h^-) have been measured by scattering 160 GeV muons off longitudinally polarised deuterons at CERN. The asymmetries were decomposed in several terms according to their expected modulation in the azimuthal angle phi of the outgoing hadron. Each term receives contributions from one or several spin and transverse-momentum-dependent parton distribution and fragmentation functions. The amplitudes of all phi-modulation terms of the hadron asymmetries integrated over the kinematic variables are found to be consistent with zero within statistical errors, while the constant terms are nonzero and equal for h^+ and h^- within the statistical errors. The dependencies of the phi-modulated terms versus the Bjorken momentum fraction x, the hadron fractional momentum z, and the hadron transverse momentum p_h^T were studied. The x dependence of the constant terms for both positive and negative hadrons is in agreement with the longitudinal double-spin hadron asymmetries, measured in semi-inclusive deep-inelastic scattering. The x dependence of the sin phi-modulation term is less pronounced than that in the corresponding HERMES data. All other dependencies of the phi-modulation amplitudes are consistent with zero within the statistical errors.Comment: 12 pages, 11 Figures; revision 1 signs in Eq 5 corrected, polishe

    Physics Performance Report for PANDA: Strong Interaction Studies with Antiprotons

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    To study fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei, the universal PANDA detector will be built. Gluonic excitations, the physics of strange and charm quarks and nucleon structure studies will be performed with unprecedented accuracy thereby allowing high-precision tests of the strong interaction. The proposed PANDA detector is a state-of-the art internal target detector at the HESR at FAIR allowing the detection and identification of neutral and charged particles generated within the relevant angular and energy range. This report presents a summary of the physics accessible at PANDA and what performance can be expected.Comment: 216 page

    Study of doubly strange systems using stored antiprotons

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    Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions
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