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A Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics
No full textInternational audienceThe nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for Weakly Interacting Massive Particles (WIMPs), while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector
Manufacture of Tl targets by electrodeposition for the study of excitation functions of 203Pb
No full textInternational audienceNatural Tl targets were manufactured by electrochemical deposition on a foil gold backing. The electrochemical parameters were defined after several experiments and reverse pulse potential was chosen to avoid the formation of filaments and dendrites. Once these parameters were established, enriched 205Tl targets were manufactured on a gold foil backing to be used to measure the cross sections for 203Pb production by deuteron induced reactions. The production yield was calculated from our excitation functions and was found to be 54 MBq/µAh in the energy interval 32.5 MeV – 30 MeV
Multiplicity and rapidity dependence of and production in p–Pb collisions at 5.02 TeV
No full textInternational audienceThe transverse-momentum spectra of Kand measured with the ALICE detector up to = 16 GeV/c in the rapidity range cQ_{\textrm{CP}}$ values are greater than unity and no significant rapidity dependence is observed
Analysis of the preliminary campaign for the PETALE program
No full textInternational audienceThe PETALE program aims to provide new experimental data to constrain the stainless steel nuclear data. In this frame, a preliminary measurement campaign has been performed to characterize the neutron flux in key positions of the CROCUS reactor and to develop analysis tools. During this preliminary campaign detailed in the present paper, an efficiency ratio technique has been developed and tested to speed up HPGe measurements by a factor of 30. A second objective of the campaign concerns the propagation of nuclear data uncertainty from the core neutron cross-sections to the reaction rates in the dosimeters. Uncertainties in the core cross sections, such as the uranium cross section, are nuisance parameters that add uncertainty to the dosimeter reaction rate calculation. This component must be fully characterized with covariances to constrain the metal reflector component for Bayesian assimilation. The experimental results are compared to the calculations with different nuclear databases for the nuclear data uncertainty propagation. A good agreement is obtained with the ENDF/B-VII.1 database and a systematic underestimation of around 5–10% in the fast range is observed with the ENDF/B-VIII.0 and JEFF-3.3 databases
JRJC 2022 - Journées de Rencontres Jeunes Chercheurs. Book of Proceedings
No full textJournées de Rencontres Jeunes Chercheurs (JRJC2022). 23-29 octobre 2022, Saint Jean de Monts (France). https://indico.in2p3.fr/event/27564/International audienc
Measurement of inclusive and leading subjet fragmentation in pp and Pb–Pb collisions at = 5.02 TeV
No full textInternational audienceThis article presents new measurements of the fragmentation properties of jets in both proton–proton (pp) and heavy-ion collisions with the ALICE experiment at the Large Hadron Collider (LHC). We report distributions of the fraction z of transverse momentum carried by subjets of radius r within jets of radius R. Charged-particle jets are reconstructed at midrapidity using the anti-k algorithm with jet radius R = 0.4, and subjets are reconstructed by reclustering the jet constituents using the anti-k algorithm with radii r = 0.1 and r = 0.2. In proton–proton collisions, we measure both the inclusive and leading subjet distributions. We compare these measurements to perturbative calculations at next-to-leading logarithmic accuracy, which suggest a large impact of threshold resummation and hadronization effects on the z distribution. In heavy-ion collisions, we measure the leading subjet distributions, which allow access to a region of harder jet frag- mentation than has been probed by previous measurements of jet quenching via hadron fragmentation distributions. The z distributions enable extraction of the parton-to-subjet fragmentation function and allow for tests of the universality of jet fragmentation functions in the quark–gluon plasma (QGP). We find no significant modification of z distributions in Pb–Pb compared to pp collisions. However, the distributions are also consistent with a hardening trend for z< 0.95, as predicted by several jet quenching models. As z → 1 our results indicate that any such hardening effects cease, exposing qualitatively new possibilities to disentangle competing jet quenching mechanisms. By comparing our results to theoretical calculations based on an independent extraction of the parton-to-jet fragmentation function, we find consistency with the universality of jet fragmentation and no indication of factorization breaking in the QGP.[graphic not available: see fulltext
Selectivity and affinity of heavy metals and radiometals for organic biomass: Implications for water remediation
No full textInternational audienceDue to both natural and anthropogenic causes, waterways have a history of contamination with different heavy metals and radiometals. Among these, thorium (Th,) uranium (U,) arsenic (As,) and strontium (Sr) are noteworthy threats to humans due to chemical and radiological toxicity. Previous research has focused on inorganic materials to remove these metals. However, the use of recyclable and biodegradable waste materials to remove toxic metals has risen. This study seeks to use pistachio shells as a model for heavy metal selectivity and affinity for organic biomasses. The influence of kinetics and pH on selectivity/affinity of the shell for the metals was investigated. The individual metal affinity seen was Th > U > As > Sr. Selectivity for Th and U over As and Sr was seen at pH 6. The maximum uptake for all metals tested occurs at pH 5 and t >= 2 h. Uptake of these metals follows pseudo-second order, intraparticle kinetics, and Freundlich isotherm. Finally, the selectivity of the shells for heavy metals was investigated using drinking water and seawater samples, with concurrent pronounced uptake of actinides and Sr being observed
W-boson production in pPb collisions at TeV and PbPb collisions at TeV
No full textInternational audienceThe production of the W bosons measured in p–Pb collisions at a centre-of-mass energy per nucleon–nucleon collision = 8.16 TeV and Pb–Pb collisions at = 5.02 TeV with ALICE at the LHC is presented. The W bosons are measured via their muonic decay channel, with the muon reconstructed in the pseudorapidity region −4 10 GeV/c. While in Pb–Pb collisions the measurements are performed in the forward (2.5 << 4) rapidity region, in p–Pb collisions, where the centre-of-mass frame is boosted with respect to the laboratory frame, the measurements are performed in the backward (−4.46 << −2.96) and forward (2.03 << 3.53) rapidity regions. The W and W production cross sections, lepton-charge asymmetry, and nuclear modification factors are evaluated as a function of the muon rapidity. In order to study the production as a function of the p–Pb collision centrality, the production cross sections of the W and W bosons are combined and normalised to the average number of binary nucleon–nucleon collision 〈N〉. In Pb–Pb collisions, the same measurements are presented as a function of the collision centrality. Study of the binary scaling of the W-boson cross sections in p–Pb and Pb–Pb collisions is also reported. The results are compared with perturbative QCD calculations, with and without nuclear modifications of the Parton Distribution Functions (PDFs), as well as with available data at the LHC. Significant deviations from the theory expectations are found in the two collision systems, indicating that the measurements can provide additional constraints for the determination of nuclear PDFs and in particular of the light-quark distributions.[graphic not available: see fulltext
<math><mrow><msup><mi>K</mi><mo>*</mo></msup><msup><mrow><mo>(</mo><mn>892</mn><mo>)</mo></mrow><mn>0</mn></msup></mrow></math> and <math><mrow><mi>ϕ</mi><mo>(</mo><mn>1020</mn><mo>)</mo></mrow></math> production in <math><mi>p</mi><mtext>-</mtext><mi>Pb</mi></math> collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>8.16</mn><mo> </mo><mi>TeV</mi></mrow></math>
No full textInternational audienceThe production of K*(892)0and ϕ(1020)resonances has been measured in p-Pb collisions at sNN = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval −0.5 < y < 0 and the transverse momentum spectra are measured for various multiplicity classes up to pT = 20 GeV/c for K*(892)0and pT = 16 GeV/c for ϕ(1020). The pT-integrated yields and mean transverse momenta are reported and compared with previous results in pp, p-Pb and Pb-Pb collisions. The xT scaling for K*(892)0and ϕ(1020)resonance production is newly tested in p-Pb collisions and found to hold in the high-pT region at Large Hadron Collider energies. The nuclear modification factors (RpPb) as a function of pT for K*0 and ϕ at sNN = 8.16 TeV are presented along with the new RpPb measurements of K*0, ϕ, Ξ, and Ω at sNN = 5.02 TeV. At intermediate pT (2–8 GeV/c), RpPb of Ξ, Ω show a Cronin-like enhancement, while K*0 and ϕ show no or little nuclear modification. At high pT (>8 GeV/c), the RpPb values of all hadrons are consistent with unity within uncertainties. The RpPb of K*(892)0and ϕ(1020)at sNN = 8.16 and 5.02 TeV show no significant energy dependence
Searching for Heavy Dark Matter near the Planck Mass with XENON1T
No full textInternational audienceMultiple viable theoretical models predict heavy dark matter particles with a mass close to the Planck mass, a range relatively unexplored by current experimental measurements. We use 219.4 days of data collected with the XENON1T experiment to conduct a blind search for signals from Multiply-Interacting Massive Particles (MIMPs). Their unique track signature allows a targeted analysis with only 0.05 expected background events from muons. Following unblinding, we observe no signal candidate events. This work places strong constraints on spin-independent interactions of dark matter particles with a mass between 110GeV/c and 210GeV/c. In addition, we present the first exclusion limits on spin-dependent MIMP-neutron and MIMP-proton cross-sections for dark matter particles with masses close to the Planck scale