238 research outputs found

    FPGA based data acquisition system for COMPASS experiment

    Full text link
    This paper discusses the present data acquisition system (DAQ) of the COMPASS experiment at CERN and presents development of a new DAQ. The new DAQ must preserve present data format and be able to communicate with FPGA cards. Parts of the new DAQ are based on state machines and they are implemented in C++ with usage of the QT framework, the DIM library, and the IPBus technology. Prototype of the system is prepared and communication through DIM between parts was tested. An implementation of the IPBus technology was prepared and tested. The new DAQ proved to be able to fulfill requirements.Comment: 8 pages, CHEP 201

    Being an Early-Career CMS Academic in the Context of Insecurity and ‘Excellence’: The Dialectics of Resistance and Compliance

    Get PDF
    Drawing on a dialectical approach to resistance, we conceptualise the latter as a multifaceted, pervasive and contradictory phenomenon. This enables us to examine the predicament in which early-career Critical Management Studies academics find themselves in the current times of academic insecurity and ‘excellence’, as gleaned through this group’s understandings of themselves as resisters and participants in the complex and contradictory forces constituting their field. We draw on 24 semi-structured interviews to map our participants’ accounts of themselves as resisters in terms of different approaches to tensions and contradictions between, on the one hand, the interviewees’ Critical Management Studies alignment and, on the other, the ethos of business school neoliberalism. Emerging from this analysis are three contingent and interlinked narratives of resistance and identity – diplomatic, combative and idealistic – each of which encapsulates a particular mode (negotiation, struggle, and laying one’s own path) of engaging with the relationship between Critical Management Studies and the business school ethos. The three narratives show how early-career Critical Management Studies academics not only use existing tensions, contradictions, overlaps and alliances between these positions to resist and comply with selected forces within each, but also contribute to the (re-)making of such overlaps, alliances, tensions and contradictions. Through this reworking of what it means to be both Critical Management Studies scholars and business school academics, we argue, early-career Critical Management Studies academics can be seen as active resisters and re-constituters of their complex field

    The Communication Library DIALOG for iFDAQ of the COMPASS Experiment

    Get PDF
    Modern experiments in high energy physics impose great demands on the reliability, the efficiency, and the data rate of Data Acquisition Systems (DAQ). This contribution focuses on the development and deployment of the new communication library DIALOG for the intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN. The iFDAQ utilizing a hardware event builder is designed to be able to readout data at the maximum rate of the experiment. The DIALOG library is a communication system both for distributed and mixed environments, it provides a network transparent inter-process communication layer. Using the high-performance and modern C++ framework Qt and its Qt Network API, the DIALOG library presents an alternative to the previously used DIM library. The DIALOG library was fully incorporated to all processes in the iFDAQ during the run 2016. From the software point of view, it might be considered as a significant improvement of iFDAQ in comparison with the previous run. To extend the possibilities of debugging, the online monitoring of communication among processes via DIALOG GUI is a desirable feature. In the paper, we present the DIALOG library from several insights and discuss it in a detailed way. Moreover, the efficiency measurement and comparison with the DIM library with respect to the iFDAQ requirements is provided

    Search for weakly interacting sub-eV particles with the OSQAR laser-based experiment: results and perspectives

    Get PDF
    Recent theoretical and experimental studies highlight the possibility of new fundamental particle physics beyond the Standard Model that can be probed by sub-eV energy experiments. The OSQAR photon regeneration experiment looks for "Light Shining through a Wall" (LSW) from the quantum oscillation of optical photons into "Weakly Interacting Sub-eV Particles" (WISPs), like axion or axion-like particles (ALPs), in a 9 T transverse magnetic field over the unprecedented length of 2×14.32 \times 14.3 m. No excess of events has been detected over the background. The di-photon couplings of possible new light scalar and pseudo-scalar particles can be constrained in the massless limit to be less than 8.0×1088.0\times10^{-8} GeV1^{-1}. These results are very close to the most stringent laboratory constraints obtained for the coupling of ALPs to two photons. Plans for further improving the sensitivity of the OSQAR experiment are presented.Comment: 7 pages, 7 figure

    Polyelectrolytes in the presence of multivalent ions: gelation versus segregation

    Full text link
    We analyze solutions of strongly charged chains bridged by linkers such as multivalent ions. The gelation induced by the strong short range electrostatic attractions is dramatically suppressed by the long range electrostatic correlations due to the charge along the uncrosslinked monomers and ions. A modified Debye-Huckel approach of crosslinked clusters of charged chains is used to determined the mean field gelation transition self-consistently. Highly dilute polyelectrolyte solutions tend to segregate macroscopically. Semidilute solutions can form gels if the Bjerrum length lBl_B and the distance between neighboring charged monomers along the chain bb are both greater than the ion size aa

    Longitudinal double spin asymmetries in single hadron quasi-real photoproduction at high pTp_T

    Get PDF
    We measured the longitudinal double spin asymmetries ALLA_{LL} for single hadron muo-production off protons and deuterons at photon virtuality Q2Q^2 < 1(GeV/c\it c)2^2 for transverse hadron momenta pTp_T in the range 0.7 GeV/c\it c to 4 GeV/c\it c . They were determined using COMPASS data taken with a polarised muon beam of 160 GeV/c\it c or 200 GeV/c\it c impinging on polarised 6LiD\mathrm{{}^6LiD} or NH3\mathrm{NH_3} targets. The experimental asymmetries are compared to next-to-leading order pQCD calculations, and are sensitive to the gluon polarisation ΔG\Delta G inside the nucleon in the range of the nucleon momentum fraction carried by gluons 0.05<xg<0.20.05 < x_g < 0.2

    Interplay among transversity induced asymmetries in hadron leptoproduction

    Get PDF
    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure

    Interplay among transversity induced asymmetries in hadron leptoproduction

    Get PDF
    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure

    Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data

    Get PDF
    Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality Q2>1 (GeV/c)2Q^2>1~({\rm GeV}/c)^2. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/cc polarised muon beam impinging on a polarised 6^6LiD target. By analysing the full range in hadron transverse momentum pTp_{\rm T}, the different pTp_{\rm T}-dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation Δg/g\Delta g/g is evaluated at leading order in pQCD at a hard scale of μ2=Q2=3(GeV/c)2\mu^2= \langle Q^2 \rangle = 3 ({\rm GeV}/c)^2. It is determined in three intervals of the nucleon momentum fraction carried by gluons, xgx_{\rm g}, covering the range 0.04 ⁣< ⁣xg ⁣< ⁣0.280.04 \!<\! x_{ \rm g}\! <\! 0.28~ and does not exhibit a significant dependence on xgx_{\rm g}. The average over the three intervals, Δg/g=0.113±0.038(stat.)±0.036(syst.)\langle \Delta g/g \rangle = 0.113 \pm 0.038_{\rm (stat.)}\pm 0.036_{\rm (syst.)} at xg0.10\langle x_{\rm g} \rangle \approx 0.10, suggests that the gluon polarisation is positive in the measured xgx_{\rm g} range.Comment: 14 pages, 6 figure
    corecore