1,456 research outputs found
Hadron production in nuclear collisions from the NA49 experiment at 158GeV/c center dot A
No full textWith its large acceptance and particle identification coverage the NA49 experiment (Fig. 1) can study hadron production in a wide range of high energy reactions [1]. Originally aimed at examining central Pb+Pb collisions for signatures of quark-gluon plasma formation, the scope of the experiment has been enhanced with the systematic study of impact parameter and projectile size dependence, as well as the inclusion. of the more elementary p+p and p+A interactions. The question is: are predicted signals of the quarkgluon plasma observed and are there discontinuities which would support the concept of hadronic phase transition?
Measurements of hadron production at CMS
No full textFirst results on hadron production using the 0.9, 2.36 and 7 TeV data are presented. The topics covered include spectra and multiplicity distributions of charged hadrons, spectra of strange hadrons, angular and Bose-Einstein correlations of charged particles. This is just the beginning of a successful physics program at the LHC, with possible future discoveries
Performance of A Parallel-plate Volume Calorimeter Prototype
No full textAn iron/gas parallel plate volume calorimeter prototype, working in the avalanche mode, has been tested using electrons of 20 to 150 GeV/c momentum with high voltages varying from 5400 to 5600 V (electric fields ranging from 36.0 to 37.3 kV/cm), and a gas mixture of CF4/CO2 (80%/20%). The collected charge has been measured as a function of the high voltage and of the electron energy. The energy resolution has also been measured. Comparisons have been made with Monte Carlo predictions. Agreement between data and simulation allows the calculation of the expected performance of a full size calorimeter
Author Correction: A portrait of the Higgs boson by the CMS experiment ten years after the discovery
No full textIn the version of this article initially published, CMS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the articl
Enhanced strange particle yields : signal of a phase of massless particles?
No full textThe yields of strange particles are calculated with the UrQMD model for p,Pb(158 AGeV)Pb collisions and compared to experimental data. The yields are enhanced in central collisions if compared to proton induced or peripheral Pb+Pb collisions. The enhancement is due to secondary interactions. Nevertheless, only a reduction of the quark masses or equivalently an increase of the string tension provides an adequate description of the large observed enhancement factors (WA97 and NA49). Furthermore, the yields of unstable strange resonances as the Lambda star(1520) resonance or the phi meson are considerably affected by hadronic rescattering of the decay products
The grid-geometry time-of-flight detector used in the NA49 experiment at the CERN-SPS
No full textThe high time and position resolution grid geometry time-of-flight spectrometer is described. It is used for particle identification as an element of the NA49 hadron detector system at the CERN-SPS. Performance and operational experience in high particle density environment of Ph + Pb collision are discussed. (C) 2000 Elsevier Science B.V. All rights reserved
Baryon stopping: A link between elementary p+p interations and controlled-centrality p+A and A+A collisions
No full textMeasurement of the top-quark mass in all-jets events in pp collisions at = 7 TeV
No full textThe mass of the top quark is measured using a sample of candidate events with at least six jets in the final state. The sample is selected from data collected with the CMS detector in pp collisions at = 7 TeV in 2011 and corresponds to an integrated luminosity of 3.54 . The mass is reconstructed for each event employing a kinematic fit of the jets to a hypothesis. The top-quark mass is measured to be 173.49 0.69(stat.) 1.21(syst.) GeV. A combination with previously published measurements in other decay modes by CMS yields a mass of 173.54 0.33(stat.) 0.96(syst.) GeV
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