2,827 research outputs found

    Charged-particle multiplicity and transverse energy in Pb-Pb collisions at sqrt(snn) = 2.76 TeV with ALICE

    Full text link
    The measurements of charged-particle multiplicity and transverse energy at mid-rapidity in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV are reported as a function of centrality. The fraction of the inelastic cross section recorded by the ALICE detector is estimated using a Glauber model. The results scaled by the number of participating nucleons are compared with pp collisions at the same collision energy, to similar results obtained at significantly lower energies, and with models based on different mechanisms for particle production in nuclear collisions.Comment: Contribution to QM 201

    A new type of lordosis and vertebral body compression in Gilthead seabream, Sparus aurata Linnaeus, 1758: aetiology, anatomy and consequences for survival

    Get PDF
    A new type of vertebral malformation is described, consisting of deformed cartilaginous neural and haemal processes and the compression and fusion of vertebral bodies. The malformation is designated as haemal vertebral compression and fusion (haemal VCF). We studied the aetiology of the malformations and described microanatomical histopathological alterations. The malformations were detected during routine quality control in one of six monitored Gilthead sea bream populations. Haemal VCF affected the posterior part of the vertebral column (haemal vertebrae). In 20% of the deformed specimens, haemal VCF was combined with lordosis. At 35dph (days post-hatching), early anatomical signs of the haemal VCF consisted of abnormal centrum mineralization, malformed cartilaginous neural and haemal processes and developing lordotic alterations. The histological examination of the deformed individuals revealed that haemal VCF is preceded by notochord abnormalities. The frequency of deformed individuals was three times higher at 35 than at 61dph (50.3% vs. 17.2%, n=157 and n=250, respectively). No signs of repair or reversion of malformations have been observed. Thus, the steep decrease in deformities in older animals suggests that haemal VCF is linked to high mortality rates. The results are discussed in respect of the possible causative factors of haemal VCF

    Photon-tagged jet measurements in Pb+Pb collisions with the CMS detector

    Full text link
    Presented are the results of a detailed study for a complete simulation of the CMS detectors at the LHC in view of the expected modification of jet fragmentation functions in central Pb+Pb collisions at (s_NN)**0.5=5.5 TeV compared to the vacuum (p+p) case. The study is based on photon-jet events, using the correlation between isolated high-transverse energy (E_T>70 GeV) photons and fully reconstructed jets, based on the information provided by the CMS calorimeters and silicon tracker.Comment: 4 pages, 4 figures, ontribution to QM'08 conferenc

    Direct photons ~basis for characterizing heavy ion collisions~

    Full text link
    After years of experimental and theoretical efforts, direct photons become a strong and reliable tool to establish the basic characteristics of a hot and dense matter produced in heavy ion collisions. The recent direct photon measurements are reviewed and a future prospect is given.Comment: 8 pages, 8 figures, Invited plenary talk at Quark Matter 200

    An exploration of ebook selection behavior in academic library collections

    Get PDF
    Academic libraries have offered ebooks for some time, however little is known about how readers interact with them while making relevance decisions. In this paper we seek to address that gap by analyzing ebook transaction logs for books in a university library

    Applicability of Monte Carlo Glauber models to relativistic heavy ion collision data

    Full text link
    The accuracy of Monte Carlo Glauber model descriptions of minimum-bias multiplicity frequency distributions is evaluated using data from the Relativistic Heavy Ion Collider (RHIC) within the context of a sensitive, power-law representation introduced previously by Trainor and Prindle (TP). Uncertainties in the Glauber model input and in the mid-rapidity multiplicity frequency distribution data are reviewed and estimated using the TP centrality methodology. The resulting errors in model-dependent geometrical quantities used to characterize heavy ion collisions ({\em i.e.} impact parameter, number of nucleon participants NpartN_{part}, number of binary interactions NbinN_{bin}, and average number of binary collisions per incident participant nucleon ν\nu) are presented for minimum-bias Au-Au collisions at sNN\sqrt{s_{NN}} = 20, 62, 130 and 200 GeV and Cu-Cu collisions at sNN\sqrt{s_{NN}} = 62 and 200 GeV. Considerable improvement in the accuracy of collision geometry quantities is obtained compared to previous Monte Carlo Glauber model studies, confirming the TP conclusions. The present analysis provides a comprehensive list of the sources of uncertainty and the resulting errors in the above geometrical collision quantities as functions of centrality. The capability of energy deposition data from trigger detectors to enable further improvements in the accuracy of collision geometry quantities is also discussed.Comment: 27 pages, 4 figures, 11 table

    First operational experience with the CMS Run Control System

    Get PDF
    The Run Control System of the Compact Muon Solenoid (CMS) experiment at CERN's new Large Hadron Collider (LHC) controls the sub-detector and central data acquisition systems and the high-level trigger farm of the experiment. It manages around 10,000 applications that control custom hardware or handle the event building and the high-level trigger processing. The CMS Run Control System is a distributed Java system running on a set of Apache Tomcat servlet containers. Users interact with the system through a web browser. The paper presents the architecture of the CMS Run Control System and deals with operational aspects during the first phase of operation with colliding beams. In particular it focuses on performance, stability, integration with the CMS Detector Control System, integration with LHC status information and tools to guide the shifter.United States. Dept. of EnergyNational Science Foundation (U.S.)European Community. Marie-Curie Research Network
    corecore