48 research outputs found

    Pion production in p+p interactions and Be+Be collisions at the CERN SPS energies

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    Evidence for the onset of deconfinement in central Pb+Pb collisions was reported by NA49 in fixed target measurements at beam momentum 30A GeV/c. This observation motivated the NA61/SHINE program started in 2009 at the CERN SPS, which, in particular, aims to study properties of the onset of deconfinement by measurements of hadron production in proton-proton, proton-nucleus and nucleus-nucleus collisions. This contribution presents spectra of charged pions produced in p+p interactions and 7^7Be+9^9Be collisions at 20A-158A GeV/c beam momentum. The NA61/SHINE results are compared with the corresponding NA49 data from central Pb+Pb collisions at the same beam momenta per nucleon

    NA61/SHINE at the CERN SPS: plans, status and first results

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    The NA61/SHINE experiment aims to discover the critical point of strongly interacting matter and study properties of the onset of deconfinement. It also to performs precise hadron production measurements for the neutrino and cosmic rays experiments. These goals will be achieved by measurements of hadron production properties in nucleus-nucleus, proton-proton and proton-nucleus interactions as a function of collision energy and size of the colliding nuclei, as well as pion-nucleus interactions. This contribution summarises the arguments of the ion program as well as presents the first physics results of the NA61 experiment

    Energy dependence of identified hadron spectra and event-by-event fluctuations in p+p interactions from NA61/SHINE at the CERN SPS

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    Two-particle correlations in azimuthal angle and pseudorapidity in inelastic p + p interactions at the CERN Super Proton Synchrotron

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    Results on two-particle ╬ö╬Ě╬ö¤Ľ correlations in inelastic p + p interactions at 20, 31, 40, 80, and 158 GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the Epos and UrQMD models.ISSN:1434-6044ISSN:1434-605

    Open charm measurements in NA61/SHINE at CERN SPS

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    The measurements of open charm production was proposed as an important tool to investigate the properties of the hot and dense matter formed in nucleus-nucleus collisions as well as to provide the means for model independent interpretation of the existing data on J/¤ł suppression. Recently, the experimental setup of the NA61/SHINE experiment was supplemented with a Vertex Detector which was motivated by the importance and the possibility of the first direct measurements of open charm meson production in heavy ion collisions at SPS energies. First test data taken in December 2016 on Pb+Pb collisions at 150A GeV/c allowed to validate the general concept of D0 meson detection via its D0 Ôćĺ ¤Ç+ + KÔłĺ decay channel and delivered a first indication of open charm production. The physics motivation of open charm measurements at SPS energies, pilot results on open charm production, and finally, the future plans of open charm measurements in the NA61/SHINE experiment after LS2 are presented

    Hidden strangeness shines in NA61/SHINE

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    Preliminary results on the ¤Ľ (1020) meson production in inelastic proton-proton collisions measured by the NA61/SHINE experiment at the CERN SPS are presented in these proceedings. The results include the first ever differential pT and y measurements at beam momenta of 40 and 80 GeV and the most ever detailed experimental data at 158GeV. The comparison of p + p to Pb + Pb results shows a non-trivial system size dependence of the widths of the rapidity distributions for ¤Ľ mesons, contrasting with that of other hadrons. The results are furthermore compared to the world data on ¤Ľ meson production, demonstrating the better accuracy achieved by the NA61/SHINE experiment, and to several models. None of the models is found to be able to describe simultaneously the shape of transverse momentum spectra, the shape of rapidity distribution and the total yield

    Operation and performance of Time Projection Chambers of SHINE / NA61 experiment at CERN

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    This paper characterizes the Time Projection Chambers (TPC) in the SHINE / NA61 exper- iment at CERN and their operation during the first run in 2007. An analysis of a change of the gas mixture in the TPCs for SHINE is included. Also the gas system of the TPCs is described

    Recent results from NA61/SHINE

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    The NA61/SHINE fixed-target experiment at the CERN SPS studies the onset of deconfinement and searches for the critical point of strongly interacting matter by measuring hadron production as a function of the collision energy and the colliding system size.The NA61/SHINE fixed-target experiment at the CERN SPS studies the onset of deconfinement and searches for the critical point of strongly interacting matter by measuring hadron production as a function of the collision energy and the colliding system size. This contribution summarises recent results on hadron spectra and fluctuations, in particular new results on charged kaon production in 7^7Be+9^9Be collisions. Also an overview of the proposed future program of NA61/SHINE is presented

    Energy dependence of negatively charged pion production in proton-proton interactions at the CERN SPS

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    This thesis presents inclusive spectra of the negatively charged pions produced in inelastic proton-proton interactions measured at five beam momenta: 20, 31, 40, 80 and 158 GeV/c. The measurements were conducted in the NA61/SHINE experiment at CERN using a system of five Time Projection Chambers. The negatively charged pion spectra were calculated based on the negatively charged hadron spectra. Contribution of hadrons other than the primary pions was removed using EPOS simulations. The results were corrected for effects related to detection, acceptance, reconstruction efficiency and the analysis technique. Two-dimensional spectra were derived as a function of rapidity and transverse momentum or transverse mass. The spectra were parametrised by widths of the rapidity distributions, inverse slope parameters of the transverse mass distributions, mean transverse masses and the total pion multiplicities. The negatively charged pion spectra in proton-proton interactions belong to a broad NA61/SHINE programme of search of the onset of deconfinement of strongly interacting matter in collisions of light and intermediate-size ions. Spectra from this thesis were compared with the pion spectra in Pb+Pb collisions at the same beam momenta per nucleon measured by the NA49 experiment. The results, in particular the energy dependence of the mean pion multiplicity, support the interpretation of the onset of deconfinement in heavy ion collisions in the SPS energy range. However, unexpected similarities in energy dependences of the shapes of the spectra obtained in proton-proton interactions and Pb+Pb collisions are revealed. Results presented in this thesis will serve for comparisons with other ongoing NA61/SHINE measurements of hadron production in p+p, Be+Be, Ar+Sc and Xe+La collisions. They widely extend the numerous, but mostly not detailed, low statistics existing p+p data

    Multiplicity and transverse momentum fluctuations in inelastic protonÔÇôproton interactions at the CERN Super Proton Synchrotron

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    Measurements of multiplicity and transverse momentum fluctuations of charged particles were performed in inelastic p+p interactions at 20, 31, 40, 80, and 158 GeV /c beam momentum. Results for the scaled variance of the multiplicity distribution and for three strongly intensive measures of multiplicity and transverse momentum fluctuations ╬ö[PT,N], ╬ú[PT,N] and ╬ŽpT are presented. For the first time the results on fluctuations are fully corrected for experimental biases. The results on multiplicity and transverse momentum fluctuations significantly deviate from expectations for the independent particle production. They also depend on charges of selected hadrons. The string-resonance Monte Carlo models Epos and Urqmd do not describe the data. The scaled variance of multiplicity fluctuations is significantly higher in inelastic p+p interactions than in central Pb+Pb collisions measured by NA49 at the same energy per nucleon. This is in qualitative disagreement with the predictions of the Wounded Nucleon Model. Within the statistical framework the enhanced multiplicity fluctuations in inelastic p+p interactions can be interpreted as due to event-by-event fluctuations of the fireball energy and/or volume.ISSN:1434-6044ISSN:1434-605
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