HAL Mines Nantes
Not a member yet
7271 research outputs found
Sort by
Measurement of the fraction of jet longitudinal momentum carried by <math display="inline"><msubsup><mi mathvariant="normal">Λ</mi><mi>c</mi><mo>+</mo></msubsup></math> baryons in <math display="inline"><mi>p</mi><mi>p</mi></math> collisions
No full textInternational audienceRecent measurements of charm-baryon production in hadronic collisions have questioned the universality of charm-quark fragmentation across different collision systems. In this work the fragmentation of charm quarks into charm baryons is probed, by presenting the first measurement of the longitudinal jet momentum fraction carried by Λc+ baryons, z∥ch, in hadronic collisions. The results are obtained in proton-proton (pp) collisions at s=13 TeV at the LHC, with Λc+ baryons and charged (track-based) jets reconstructed in the transverse momentum intervals of 3≤pTΛc+<15 GeV/c and 7≤pTjet ch<15 GeV/c, respectively. The z∥ch distribution is compared to a measurement of D0-tagged charged jets in pp collisions as well as to pythia 8 simulations. The data hints that the fragmentation of charm quarks into charm baryons is softer with respect to charm mesons, in the measured kinematic interval, as predicted by hadronization models which include color correlations beyond leading-color in the string formation
Bottomonium evolution with in-medium heavy quark potential from lattice QCD
No full textInternational audienceThe static properties and dynamic evolution of bottomonium states in a hot QCD medium are investigated through the Schrödinger equation with complex heavy quark potentials, which are presented recently in lattice QCD study and with three different extractions. This approach builds a direct connection between the in-medium heavy quark potentials from the lattice QCD to the experimental observables. The yields and nuclear modification factors of bottomonium in Pb-Pb collisions at are calculated in this work. Our results show a large suppression of the bottomonium yield in heavy ion collisions due to the large imaginary potential. To understand bottomonium based on lattice QCD potentials, we propose a fomration time for bottomonium states and find that experimental data can be well explained with the heavy quark potential extracted by the Padé fit, which shows no color screening in the real part potential
Measurement of f(1285) production in pp collisions at = 13 TeV
No full textInternational audienceThis study presents the first measurement of the f(1285) resonance using the ALICE detector in inelastic proton--proton collisions at a center-of-mass energy of 13 TeV. The resonance is reconstructed at midrapidity ( 0.5) through the hadronic decay channel f. Key measurements include the determination of its mass, transverse-momentum integrated yield, and average transverse momentum. Additionally, the ratio of the transverse-momentum integrated yield of f(1285) to pion is compared with calculations from the canonical statistical hadronization model. The model calculation, assuming a zero total strangeness content for f(1285), reproduces the data within 1 deviation, shedding light on the quark composition of f(1285)
Upgrades and performances of ALICE on muon detection at forward rapidities for LHC Run 3
No full textInternational audienceDuring runs 1 and 2 of the LHC, the ALICE Muon Spectrometer (MS) has produced many results at forward pseudorapidities (2.5<η<4) and down to pT=0, mainly on quarkonia and open heavy flavors. However, the frontal absorber of the MS prevented the separation of charm and beauty contributions because of the lack of spatial resolution in the interaction point region. To remove this limitation, a new tracker, the Muon Forward Tracker (MFT), has been installed in front of the frontal absorber. Covering almost the full acceptance of the MS, the MFT is composed of 936 high-performance pixel sensors (ALPIDE). In addition, the front-end and the readout electronics of the MS have been upgraded to cope with the increase of event rate from about 10kHz to 50kHz in Pb-Pb collisions.After an overview of the design of these upgrades, this contribution will focus on the performance of the muon detection in terms of data taking, track reconstruction and measurement of displaced vertices
The DARWIN project, A Liquid Xenon Observatory For Rare Event Searches
No full textInternational audienc
Investigating strangeness enhancement with multiplicity in pp collisions using angular correlations
No full textInternational audienceA study of strange hadron production associated with hard scattering processes and with the underlying event is conducted to investigate the origin of the enhanced production of strange hadrons in small collision systems characterised by large charged-particle multiplicities. For this purpose, the production of the single-strange meson and the double-strange baryon is measured, in each event, in the azimuthal direction of the highest- particle (``trigger" particle), related to hard scattering processes, and in the direction transverse to it in azimuth, associated with the underlying event, in pp collisions at TeV and TeV using the ALICE detector at the LHC. The per-trigger yields of and are dominated by the transverse-to-leading production (i.e., in the direction transverse to the trigger particle), whose contribution relative to the toward-leading production is observed to increase with the event charged-particle multiplicity. The transverse-to-leading and the toward-leading / yield ratios increase with the multiplicity of charged particles, suggesting that strangeness enhancement with multiplicity is associated with both hard scattering processes and the underlying event. The relative production of with respect to is higher in transverse-to-leading processes over the whole multiplicity interval covered by the measurement. The and per-trigger yields and yield ratios are compared with predictions of three different phenomenological models, namely PYTHIA 8.2 with the Monash tune, PYTHIA 8.2 with ropes and EPOS LHC. The comparison shows that none of them can quantitatively describe either the transverse-to-leading or the toward-leading yields of and
Recent progress in ruthenium chemistry for establishing a 103Ru/103mRh generator for Auger therapy
No full textInternational audienceThe most challenging task for establishing a Ru-103/Rh-103m generator for Auger therapy, is to reach an effective separation between the two radionuclides because of the highly unpredictable, very complicated and poorly understood chemistry. In HCl, this work was able to evidence the formation of Ru colloids. It has been evidenced that the starting material of Ru, time and temperature have a strong influence on Ru speciation, but no polynuclear species of ruthenium-chloride was observed. This work has showed that it is fully possible to control the speciation of ruthenium, especially Ru(IV), within a mononuclear species; that is a huge step forward compared to literature
Effective Field Theory and Inelastic Dark Matter Results from XENON1T
No full textInternational audienceIn this work, we expand on the XENON1T nuclear recoil searches to study the individual signals of dark matter interactions from operators up to dimension-eight in a Chiral Effective Field Theory (ChEFT) and a model of inelastic dark matter (iDM). We analyze data from two science runs of the XENON1T detector totaling 1 tonneyear exposure. For these analyses, we extended the region of interest from [4.9, 40.9]keV to [4.9, 54.4]keV to enhance our sensitivity for signals that peak at nonzero energies. We show that the data is consistent with the background-only hypothesis, with a small background over-fluctuation observed peaking between 20 and 50keV, resulting in a maximum local discovery significance of 1.7 for the VectorVector () ChEFT channel for a dark matter particle of 70GeV/c, and for an iDM particle of 50GeV/c with a mass splitting of 100keV/c. For each model, we report 90 % confidence level (CL) upper limits. We also report upper limits on three benchmark models of dark matter interaction using ChEFT where we investigate the effect of isospin-breaking interactions. We observe rate-driven cancellations in regions of the isospin-breaking couplings, leading to up to 6 orders of magnitude weaker upper limits with respect to the isospin-conserving case
Optimization of the Separating Resin for establishing a 103-Ru/ 103m-Rh Generator
No full textInternational audienceIntroduction: Auger emitters are investigated for their application in radiotherapy. Among them, 103mRh can be produced from 103Ru.1 The most challenging task is to reach an effective separation between the radionuclides concerned. Separations of these two elements by liquid-liquid extraction2 or by distillation3 are already known. Nevertheless, the use of a chromatographic-type generator (103Ru/103mRh) would be more practical for widespread research use, and in particular in nuclear medicine services. The main objective is to find an ionic exchange resin able to separate these two elements efficiently. Methods: Several resins (Dowex 1x8 Cl-, Resin 1 Triskem®, Resin 2 Triskem®) have been considered to evaluate their capacity to separate Ru and Rh. Preliminary tests have been achieved. The conditions are batch experiments, [Ru]=[Rh]~10-5M. The elements were analyzed by ICP-OES or ICP-MS (initial and final concentrations) in order to establish the Kd values on the different resins tested. For the most promising resin, additional studies (influence of the raw material, repeatability, reproducibility) and column tests have been conducted. Results: Based on the preliminary results, Resin 2 Triskem® seems to be the most suitable candidate for Ru/Rh separation. More than 90% of Ru initially introduced is retained on the resin, and no Rh is retained. Age of Ru solutions has an impact on the speciation of Ruthenium and its retention on the resin.Discussion: Resin 2 Triskem® appears to be able to be used in the chromatographic-type generator (103Ru/103mRh). More studies need to be conducted to certify its potential, especially Ru breakthrough evaluation. (1)Filosofov and al. Potent Candidates for Targeted Auger Therapy: Production and Radiochemical Considerations. Nuclear Medicine and Biology 2021, 94–95, 1–19. (2)Al-Bazi and al. Extraction of Ruthenium Thiocyanate and Its Separation from Rhodium by Polyurethane Foam. Talanta 1984, 31 (3), 189–193.(3)Kurbatov and al. Isolation of Carrier Free Rhodium from Ruthenium Targets. Journal of Inorganic and Nuclear Chemistry 1961, 18, 19–23