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    Thermalization of weakly coupled non-Abelian plasmas at next-to-leading order

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    HAL CCSD
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    International audienceWe employ the QCD kinetic theory, including next-to-leading(NLO) order corrections in coupling constant, to study the evolution of weakly coupled non-Abelian plasmas towards thermal equilibrium. For two characteristic far-from-equilibrium systems with either under- or over-occupied initial conditions, the NLO corrections remain well under control for a wide range of couplings, and the overall effect of NLO corrections is a reduction in the time required for thermalization

    Groundwater Vulnerability and Potentially Toxic Elements Associated with the Iron Mining District of Ouixane (Northeast of Morocco)

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    HAL CCSD
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    International audienceThis study aims to investigate the groundwater vulnerability concerning potentially toxic elements in the vicinity of the abandoned iron mine of Ouixane (Morocco). A modified DRASTIC method (DRSTI) is proposed with satisfactory results. High vulnerability zones represent 40% of the study area, while medium and low vulnerability represent, respectively, 42% and 18% of the study area. These results have been validated by groundwater geochemical analyses of potentially toxic elements carried out in the framework of previous studies in the same area. Thus, the superposition of the waste rock and tailings map with the vulnerability map showed that the latter is located in areas of high to medium vulnerability and therefore constitutes the main cause of the deterioration of the geochemical quality of groundwater. Otherwise, the vulnerability method showed that the main parameters that significantly affect the vulnerability are: the depth of water (D), net recharge (R), and the unsaturated zone (I), while the other parameters do not significantly affect the model used and do not have much influence on the results of the vulnerability assessment. The method used allowed us to locate the most vulnerable areas to potentially metallic toxic elements pollution resulting from the abandoned iron mine of Ouixane, and it constitutes a tool for decision support and for developing effective action plans to mitigate and monitor the effects of the transfer of potentially toxic elements pollution to groundwater.</jats:p

    Local environment of iodine dissolved as iodate in high-pressure aluminoborosilicate glasses: A I K-edge x-ray absorption spectroscopic study

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    American Institute of Physics
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    International audienceThe use of high-pressure synthesis conditions to produce I-bearing aluminoborosilicate represents a promising issue for the immobilization of 129I radioisotope. Furthermore, iodine appears to be more solubilized in glasses under its iodate (I5+) form rather than its iodide (I−) form. Currently, the local atomic environment for iodine is poorly constrained for I− and virtually unknown for I5+ or I7+. We used I K-edge x-ray absorption spectroscopy conducted at 20 K for determining the local atomic environment of iodine dissolved as I−, I5+, and I7+ in a series of aluminoborosilicate glasses. We determined that I− is surrounded by either Na+ or Ca2+ in agreement with previous studies. The signal collected from EXAFS reveals that I5+ is surrounded invariably by three oxygen atoms forming an IO3− cluster charge compensated by Na+ and/or Ca2+. The I–O distance in iodate dissolved in glass is comparable to the I–O distance in crystalline compounds at ∼1.8 Å. The distance to the second nearest neighbor (Na+ or Ca2+) is also constant at ∼3.2 Å. This derived distance is identical to the distance between I− and Na+ or Ca2+ in the case of iodide local environment. For one sample containing iodate and periodate, the distinction between the local environment of I5+ and I7+ could not be made, suggesting that both environments have comparable EXAFS signals

    Projet BePAT : BeaQuant, a digital autoradiograph for the production of radionuclides for nuclear medicine applications

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    HAL CCSD
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    International audienc

    R2D2 (Rare Decays with Radial Detector) status & Projects @ LSM

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    HAL CCSD
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    International audienc

    Inclusive, prompt and non-prompt J/ψ production at midrapidity in p-Pb collisions at sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    Springer
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    International audienceA measurement of inclusive, prompt, and non-prompt J/ψ production in p-Pb collisions at a nucleon-nucleon centre-of-mass energy sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV is presented. The inclusive J/ψ mesons are reconstructed in the dielectron decay channel at midrapidity down to a transverse momentum pT_{T} = 0. The inclusive J/ψ nuclear modification factor RpPb_{pPb} is calculated by comparing the new results in p-Pb collisions to a recently measured proton-proton reference at the same centre-of-mass energy. Non-prompt J/ψ mesons, which originate from the decay of beauty hadrons, are separated from promptly produced J/ψ on a statistical basis for pT_{T} larger than 1.0 GeV/c. These results are based on the data sample collected by the ALICE detector during the 2016 LHC p-Pb run, corresponding to an integrated luminosity Lint \mathcal{L} _{int} = 292 ± 11 μb−1^{−1}, which is six times larger than the previous publications. The total uncertainty on the pT_{T}-integrated inclusive J/ψ and non-prompt J/ψ cross section are reduced by a factor 1.7 and 2.2, respectively. The measured cross sections and RpPb_{pPb} are compared with theoretical models that include various combinations of cold nuclear matter effects. From the non-prompt J/ψ production cross section, the bb‾ \mathrm{b}\overline{\mathrm{b}} production cross section at midrapidity, dσbb‾ {\mathrm{d}\sigma}_{\mathrm{b}\overline{\mathrm{b}}} /dy, and the total cross section extrapolated over full phase space, σbb‾ {\sigma}_{\mathrm{b}\overline{\mathrm{b}}} , are derived.[graphic not available: see fulltext

    Dynamical systems with benign ghosts

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    American Physical Society
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    International audienceWe consider finite and infinite-dimensional ghost-ridden dynamical systems whose Hamiltonians involve nonpositive definite kinetic terms. We point out the existence of three classes of such systems where the ghosts are benign, i.e., systems whose evolution is unlimited in time: (i) systems obtained from the variation of bounded-motion systems; (ii) systems describing motions over certain Lorentzian manifolds and (iii) higher-derivative models related to certain modified Korteweg-de Vries equations

    Investigating charm production and fragmentation via azimuthal correlations of prompt D mesons with charged particles in pp collisions at s=13\mathbf {\sqrt{ s} = 13} TeV

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    Springer Verlag (Germany)
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    International audienceAngular correlations of heavy-flavour and charged particles in high-energy proton–proton collisions are sensitive to the production mechanisms of heavy quarks and to their fragmentation as well as hadronisation processes. The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in proton–proton collisions at a centre-of-mass energy of s=13\sqrt{s} = 13 TeV with the ALICE detector is reported, considering D0\mathrm D^{0} , D+\mathrm D^{+} , and D∗+\mathrm D^{*+} mesons in the transverse-momentum interval 30.33 0.3 GeV/cc and pseudorapidity ∣η∣<0.8|\eta | < 0.8. This measurement has an improved precision and provides an extended transverse-momentum coverage compared to previous ALICE measurements at lower energies. The study is also performed as a function of the charged-particle multiplicity, showing no modifications of the correlation function with multiplicity within uncertainties. The properties and the transverse-momentum evolution of the near- and away-side correlation peaks are studied and compared with predictions from various Monte Carlo event generators. Among those considered, PYTHIA8 and POWHEG+PYTHIA8 provide the best description of the measured observables. The obtained results can provide guidance on tuning the generators

    Production of light (anti)nuclei in pp collisions at s \sqrt{s} = 13 TeV

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    Springer
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    International audienceUnderstanding the production mechanism of light (anti)nuclei is one of the key challenges of nuclear physics and has important consequences for astrophysics, since it provides an input for indirect dark-matter searches in space. In this paper, the latest results about the production of light (anti)nuclei in pp collisions at s \sqrt{s} = 13 TeV are presented, focusing on the comparison with the predictions of coalescence and thermal models. For the first time, the coalescence parameters B2_{2} for deuterons and B3_{3} for helions are compared with parameter-free theoretical predictions that are directly constrained by the femtoscopic measurement of the source radius in the same event class. A fair description of the data with a Gaussian wave function is observed for both deuteron and helion, supporting the coalescence mechanism for the production of light (anti)nuclei in pp collisions. This method paves the way for future investigations of the internal structure of more complex nuclear clusters, including the hypertriton.[graphic not available: see fulltext

    Measurement of Prompt D0^{0}, Λc+\Lambda_{c}^{+}, and Σc0,++\Sigma_{c}^{0,++}(2455) Production in Proton–Proton Collisions at s\sqrt s = 13  TeV

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    American Physical Society
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    International audienceThe pT-differential production cross sections of prompt D0, Λc+, and Σc0,++(2455) charmed hadrons are measured at midrapidity (|y|&lt;0.5) in pp collisions at s=13  TeV. This is the first measurement of Σc0,++ production in hadronic collisions. Assuming the same production yield for the three Σc0,+,++ isospin states, the baryon-to-meson cross section ratios Σc0,+,++/D0 and Λc+/D0 are calculated in the transverse momentum (pT) intervals 2&lt;pT&lt;12 and 1&lt;pT&lt;24  GeV/c. Values significantly larger than in e+e- collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the Σc. The feed-down contribution to Λc+ production from Σc0,+,++ is also reported and is found to be larger than in e+e- collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronization mechanisms implemented in the models

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