HAL Mines Nantes
Not a member yet
    7271 research outputs found

    Bottom energy loss and non-prompt J/ψJ/\psi production in relativistic heavy ion collisions

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienceWe study the momentum and centrality dependence of the non-prompt J/ψJ/\psi nuclear modification factors (RAAR_{AA}), which comes from the BB hadrons decay, in Pb-Pb collisions at the Large Hadron Collider. Bottom quarks are produced in the parton hard scatterings and suffer energy loss in the quark-gluon plasma and the hadronic gas, where the spatial and time evolution of the medium is described with the hydrodynamic equations. Medium-induced elastic scatterings and the radiation in bottom quarks are included in the energy loss of bottom quarks. The hadronization process of bottom quarks is described with the instantaneous coalescence model. After considering both cold and hot nuclear matter effects in Pb-Pb collisions at sNN=5.02\sqrt{s_{NN}}=5.02 TeV, we calculated the RAAR_{AA} and also the elliptic flows of non-prompt J/ψJ/\psi from the decay of BB mesons at different centralities and transverse momentum bins. The RAAR_{AA} and v2v_2 of non-prompt J/ψJ/\psi sensitive to the hot medium reflect and centrality supply an opportunity to study the bottom quarks energy loss in the hot medium

    Coordination and thermodynamic properties of aqueous protactinium(V) by computational chemistry techniques

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienc

    The Triggerless Data Acquisition System of the XENONnT Experiment

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienceThe XENONnT detector uses the latest and largest liquid xenon-based time projection chamber (TPC) operated by the XENON Collaboration, aimed at detecting Weakly Interacting Massive Particles and conducting other rare event searches. The XENONnT data acquisition (DAQ) system constitutes an upgraded and expanded version of the XENON1T DAQ system. For its operation, it relies predominantly on commercially available hardware accompanied by open-source and custom-developed software. The three constituent subsystems of the XENONnT detector, the TPC (main detector), muon veto, and the newly introduced neutron veto, are integrated into a single DAQ, and can be operated both independently and as a unified system. In total, the DAQ digitizes the signals of 698 photomultiplier tubes (PMTs), of which 253 from the top PMT array of the TPC are digitized twice, at ×10\times10 and ×0.5\times0.5 gain. The DAQ for the most part is a triggerless system, reading out and storing every signal that exceeds the digitization thresholds. Custom-developed software is used to process the acquired data, making it available within O(10 s)\mathcal{O}\left(10\text{ s}\right) for live data quality monitoring and online analyses. The entire system with all the three subsystems was successfully commissioned and has been operating continuously, comfortably withstanding readout rates that exceed ∼500\sim500 MB/s during calibration. Livetime during normal operation exceeds 99%99\% and is ∼90%\sim90\% during most high-rate calibrations. The combined DAQ system has collected more than 2 PB of both calibration and science data during the commissioning of XENONnT and the first science run

    Inclusive and multiplicity dependent production of electrons from heavy-flavour hadron decays in pp and p−-Pb collisions

    Author
    Publication venue
    Springer
    Publication date
    Field of study
    No full text
    International audienceMeasurements of the production of electrons from heavy-flavour hadron decays in pp collisions at s=13\sqrt{s} = 13 TeV at midrapidity with the ALICE detector are presented down to a transverse momentum (pTp_{\rm T}) of 0.2 GeV/c/c and up to pT=35p_{\rm T} = 35 GeV/c/c, which is the largest momentum range probed for inclusive electron measurements in ALICE. In p−-Pb collisions, the production cross section and the nuclear modification factor of electrons from heavy-flavour hadron decays are measured in the pTp_{\rm T} range 0.5<pT<260.5 < p_{\rm T} < 26 GeV/c/c at sNN=8.16\sqrt{s_{\rm NN}} = 8.16 TeV. The nuclear modification factor is found to be consistent with unity within the statistical and systematic uncertainties. In both collision systems, first measurements of the yields of electrons from heavy-flavour hadron decays in different multiplicity intervals normalised to the multiplicity-integrated yield (self-normalised yield) at midrapidity are reported as a function of the self-normalised charged-particle multiplicity estimated at midrapidity. The self-normalised yields in pp and p−-Pb collisions grow faster than linear with the self-normalised multiplicity. A strong pTp_{\rm T} dependence is observed in pp collisions, where the yield of high-pTp_{\rm T} electrons increases faster as a function of multiplicity than the one of low-pTp_{\rm T} electrons. The measurement in p−-Pb collisions shows no pTp_{\rm T} dependence within uncertainties. The self-normalised yields in pp and p−-Pb collisions are compared with measurements of other heavy-flavour, light-flavour, and strange particles, and with Monte Carlo simulations

    The JUNO experiment Top Tracker

    Author
    Publication venue
    Elsevier
    Publication date
    Field of study
    No full text
    20 pagesInternational audienceThe main task of the Top Tracker detector of the neutrino reactor experiment Jiangmen Underground Neutrino Observatory (JUNO) is to reconstruct and extrapolate atmospheric muon tracks down to the central detector. This muon tracker will help to evaluate the contribution of the cosmogenic background to the signal. The Top Tracker is located above JUNO's water Cherenkov Detector and Central Detector, covering about 60% of the surface above them. The JUNO Top Tracker is constituted by the decommissioned OPERA experiment Target Tracker modules. The technology used consists in walls of two planes of plastic scintillator strips, one per transverse direction. Wavelength shifting fibres collect the light signal emitted by the scintillator strips and guide it to both ends where it is read by multianode photomultiplier tubes. Compared to the OPERA Target Tracker, the JUNO Top Tracker uses new electronics able to cope with the high rate produced by the high rock radioactivity compared to the one in Gran Sasso underground laboratory. This paper will present the new electronics and mechanical structure developed for the Top Tracker of JUNO along with its expected performance based on the current detector simulation

    Nuclear physics midterm plan at Legnaro National Laboratories (LNL)

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienceThe next years will see the completion of the radioactive ion beam facility SPES (Selective Production of Exotic Species) and the upgrade of the accelerators complex at Istituto Nazionale di Fisica Nucleare – Legnaro National Laboratories (LNL) opening up new possibilities in the fields of nuclear structure, nuclear dynamics, nuclear astrophysics, and applications. The nuclear physics community has organised a workshop to discuss the new physics opportunities that will be possible in the near future by employing state-of-the-art detection systems. A detailed discussion of the outcome from the workshop is presented in this report

    Multiplicity dependence of charged-particle production in pp, p-Pb, Xe-Xe and Pb-Pb collisions at the LHC

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienceMultiplicity (NchN_{\rm ch}) distributions and transverse momentum (pTp_{\rm T}) spectra of inclusive primary charged particles in the kinematic range of ∣η∣<0.8|\eta| < 0.8 and 0.15 GeV/cc<pT<< p_{T} < 10 GeV/cc are reported for pp, p-Pb, Xe-Xe and Pb-Pb collisions at centre-of-mass energies per nucleon pair ranging from sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV up to 1313 TeV. A sequential two-dimensional unfolding procedure is used to extract the correlation between the transverse momentum of primary charged particles and the charged-particle multiplicity of the corresponding collision. This correlation sharply characterises important features of the final state of a collision and, therefore, can be used as a stringent test of theoretical models. The multiplicity distributions as well as the mean and standard deviation derived from the pTp_{\rm T} spectra are compared to state-of-the-art model predictions. Providing these fundamental observables of bulk particle production consistently across a wide range of collision energies and system sizes can serve as an important input for tuning Monte Carlo event generators

    U(VI) retention in compact Callovo-Oxfordian clay stone at temperature (20–80 °C); What is the applicability of adsorption models?

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienceIn the context of the radioactive waste management in deep geological formations, U(VI) retention by intact Callovo-Oxfordian claystone (COx) was studied by percolation-type experiments at 20 and 80 degrees C. The experimental results were confronted with modelling prediction based on a published adsorption model developed from dispersed media in the 20-80 degrees C temperature range. For the experiments at 20 degrees C, the adsorption model allowed to explain the results for the intact system; the retention was weak (R-d similar to 10 L.kg(-1)) and the analysis of the COx phases at the end of the experiment confirmed a retention of U by the clay fraction. The adsorption model in temperature also explained the observed trend of increasing retention with increasing temperature. However, it underestimated the temperature effect on the adsorption of U(VI) by the COx clay fraction, and other phases contributed to the retention. Solid-state analysis of the percolation-doped samples indicated a reactivity in the order pyrite>clay>calcite phases. The transposition of the knowledge at 20 degrees C from the dispersed system to the intact medium was therefore not possible at 80 degrees C for the studied U(VI)/COx system

    Photoproduction of low-pTp_{\rm T} J/ψ\psi from peripheral to central Pb−-Pb collisions at 5.02 TeV

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienceAn excess of J/ψ\psi yield at very low transverse momentum (pT<0.3p_{\rm T} < 0.3 GeV/cc), originating from coherent photoproduction, is observed in peripheral and semicentral hadronic Pb−-Pb collisions at a center-of-mass energy per nucleon pair of sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV. The measurement is performed with the ALICE detector via the dimuon decay channel at forward rapidity (2.5<y<42.5<y<4). The nuclear modification factor at very low pTp_{\rm T} and the coherent photoproduction cross section are measured as a function of centrality down to the 10% most central collisions. These results extend the previous study at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV, confirming the clear excess over hadronic production in the pTp_{\rm T} range 0−-0.3 GeV/cc and the centrality range 70−-90%, and establishing an excess with a significance greater than 5σ\sigma also in the 50−-70% and 30−-50% centrality ranges. The results are compared with earlier measurements at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV and with different theoretical predictions aiming at describing how coherent photoproduction occurs in hadronic interactions with nuclear overlap

    Study of charged particle production at high pT using event topology in pp, p–Pb and Pb–Pb collisions at <math altimg="si1.svg"><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi mathvariant="normal">NN</mi></mrow></msub></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>5.02</mn></math>TeV

    Author
    Publication venue
    HAL CCSD
    Publication date
    Field of study
    No full text
    International audienceThis letter reports measurements which characterize the underlying event associated with hard scatterings at mid-pseudorapidity (|η|&lt;0.8) in pp, p–Pb and Pb–Pb collisions at centre-of-mass energy per nucleon pair, sNN=5.02TeV. The measurements are performed with ALICE at the LHC. Different multiplicity classes are defined based on the event activity measured at forward rapidities. The hard scatterings are identified by the leading particle defined as the charged particle with the largest transverse momentum (pT) in the collision and having 8 &lt;pT&lt;15GeV/c. The pT spectra of associated particles (0.5 ≤pT&lt;6GeV/c) are measured in different azimuthal regions defined with respect to the leading particle direction: toward, transverse, and away. The associated charged particle yields in the transverse region are subtracted from those of the away and toward regions. The remaining jet-like yields are reported as a function of the multiplicity measured in the transverse region. The measurements show a suppression of the jet-like yield in the away region and an enhancement of high-pT associated particles in the toward region in central Pb–Pb collisions, as compared to minimum-bias pp collisions. These observations are consistent with previous measurements that used two-particle correlations, and with an interpretation in terms of parton energy loss in a high-density quark gluon plasma. These yield modifications vanish in peripheral Pb–Pb collisions and are not observed in either high-multiplicity pp or p–Pb collisions

    875

    full texts

    7,271

    metadata records
    Updated in last 30 days.
    HAL Mines Nantes
    Access Repository Dashboard
    Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇