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Nuclear Cross-Section of Proton-Induced Reactions on Enriched Ti Targets for the Production of TheranosticSc Radionuclide,Sc,Sc,Sc,Sc, andV
No full textInternational audienceThe cross-sections of the 48Ti(p,x)47Sc, 46cSc, 44mSc, 44gSc, 43Sc, and 48V nuclear reactions were measured from 18 to 70 MeV, with particular attention to 47Sc production. Enriched 48Ti powder was deposited on an aluminum backing and the obtained targets were characterized via elastic backscattering spectroscopy at the INFN-LNL. Targets were exposed to low-intensity proton irradiation using the stacked-foils technique at the ARRONAX facility. Activated samples were measured using γ-spectrometry; the results were compared with the data int he literature and the theoretical TALYS-based values. A regular trend in the new values obtained from the different irradiation runs was noted, as well as a good agreement with the literature data, for all the radionuclides of interest: 47Sc, 46cSc, 44mSc, 44gSc, 43Sc, and 48V. 47Sc production was also discussed, considering yield and radionuclidic purity, for different 47Sc production scenarios.</jats:p
Searches for neutrino counterparts of gravitational waves from the LIGO/Virgo third observing run with KM3NeT
No full textInternational audienceThe KM3NeT neutrino telescope is currently being deployed at two different sites in the Mediterranean Sea. First searches for astrophysical neutrinos have been performed using data taken with the partial detector configuration already in operation. The paper presents the results of two independent searches for neutrinos from compact binary mergers detected during the third observing run of the LIGO and Virgo gravitational wave interferometers. The first search looks for a global increase in the detector counting rates that could be associated with inverse beta decay events generated by MeV-scale electron anti-neutrinos. The second one focuses on upgoing track-like events mainly induced by muon (anti-)neutrinos in the GeV--TeV energy range. Both searches yield no significant excess for the sources in the gravitational wave catalogs. For each source, upper limits on the neutrino flux and on the total energy emitted in neutrinos in the respective energy ranges have been set. Stacking analyses of binary black hole mergers and neutron star-black hole mergers have also been performed to constrain the characteristic neutrino emission from these categories
Efficient solver of relativistic hydrodynamics with implicit Runge-Kutta method
No full textInternational audienceWe propose a new method to solve the relativistic hydrodynamic equations based on an implicit Runge-Kutta method with an optimized fixed-point iterative solver. In the case of ideal hydrodynamics, the accuracy and computational cost of our new method are compared with those of explicit ones for the (1+1)-dimensional Riemann problem, as well as the (2+1)-dimensional Gubser flow and event-by-event initial conditions for heavy-ion collisions generated by TrENTo. We demonstrate that the solver converges with only one iteration in most cases, and as a result, the implicit method requires a smaller computational cost than the explicit one at the same accuracy in these cases
Heavy flavor as a probe of hot QCD matter produced in proton-proton collisions
No full textInternational audienceWe investigate yields, elliptic flow , baryon-to-meson ratios, and correlations of various charmed hadrons in high energy proton-proton () collisions, employing the newly developed EPOS4HQ approach, which reproduces basic experimental data concerning light hadrons. All the above-mentioned heavy flavor observables can be well explained, essentially due to the presence of deconfined matter, which in particular affects dramatically, although the energy loss is small
Pseudorapidity dependence of anisotropic flow and its decorrelations using long-range multiparticle correlations in Pb-Pb and Xe-Xe collisions
No full textInternational audienceThe pseudorapidity dependence of elliptic (), triangular (), and quadrangular () flow coefficients of charged particles measured in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of TeV and in Xe-Xe collisions at TeV with ALICE at the LHC are presented. The measurements are performed in the pseudorapidity range for various centrality intervals using two- and multi-particle cumulants with the subevent method. The flow probability density function (p.d.f.) is studied with the ratio of flow coefficient calculated with four- and two-particle cumulant, and suggests that the variance of flow p.d.f. is independent of pseudorapidity. The decorrelation of the flow vector in the longitudinal direction is probed using two-particle correlations. The results measured with respect to different reference regions in pseudorapidity exhibit differences, argued to be a result of saturating decorrelation effect above a certain pseudorapidity separation, in contrast to previous publications which assign this observation to non-flow effects. The results are compared to dimensional hydrodynamic and the AMPT transport model calculations. Neither of the models is able to simultaneously describe the pseudorapidity dependence of measurements of anisotropic flow and its fluctuations. The results presented in this work highlight shortcomings in our current understanding of initial conditions and subsequent system expansion in the longitudinal direction. Therefore, they provide input for its improvement
Measurement of inclusive charged-particle jet production in pp and p-Pb collisions at TeV
No full textInternational audienceMeasurements of inclusive charged-particle jet production in pp and p-Pb collisions at center-of-mass energy per nucleon-nucleon collision TeV and the corresponding nuclear modification factor are presented, using data collected with the ALICE detector at the LHC. Jets are reconstructed in the central rapidity region from charged particles using the anti- algorithm with resolution parameters , 0.3, and 0.4. The -differential inclusive production cross section of charged-particle jets, as well as the corresponding cross-section ratios, are reported for pp and p-Pb collisions in the transverse momentum range GeV/ and GeV/, respectively, together with the nuclear modification factor in the range GeV/. The analysis extends the range of the previously-reported charged-particle jet measurements by the ALICE Collaboration. The nuclear modification factor is found to be consistent with one and independent of the jet resolution parameter with the improved precision of this study, indicating that the possible influence of cold nuclear matter effects on the production cross section of charged-particle jets in p-Pb collisions at TeV is smaller than the current precision. The obtained results are in agreement with other minimum bias jet measurements available for RHIC and LHC energies, and are well reproduced by the NLO perturbative QCD POWHEG calculations with parton shower provided by PYTHIA8 as well as by JETSCAPE simulations
The Power Board of the KM3NeT Digital Optical Module: design, upgrade, and production
No full textInternational audienceThe KM3NeT Collaboration is building an underwater neutrino observatory at the bottom of the Mediterranean Sea consisting of two neutrino telescopes, both composed of a three-dimensional array of light detectors, known as digital optical modules. Each digital optical module contains a set of 31 three inch photomultiplier tubes distributed over the surface of a 0.44 m diameter pressure-resistant glass sphere. The module includes also calibration instruments and electronics for power, readout and data acquisition. The power board was developed to supply power to all the elements of the digital optical module. The design of the power board began in 2013, and several prototypes were produced and tested. After an exhaustive validation process in various laboratories within the KM3NeT Collaboration, a mass production batch began, resulting in the construction of over 1200 power boards so far. These boards were integrated in the digital optical modules that have already been produced and deployed, 828 until October 2023. In 2017, an upgrade of the power board, to increase reliability and efficiency, was initiated. After the validation of a pre-production series, a production batch of 800 upgraded boards is currently underway. This paper describes the design, architecture, upgrade, validation, and production of the power board, including the reliability studies and tests conducted to ensure the safe operation at the bottom of the Mediterranean Sea throughout the observatory's lifespa
Search for quasi-particle scattering in the quark-gluon plasma with jet splittings in pp and PbPb collisions at = 5.02 TeV
No full textInternational audienceThe ALICE Collaboration reports measurements of the large relative transverse momentum () component of jet substructure in pp and in central and semicentral PbPb collisions at center-of-mass energy per nucleon pair TeV. Enhancement in the yield of such large- emissions in central PbPb collisions is predicted to arise from partonic scattering with quasi-particles of the quark-gluon plasma. The analysis utilizes charged-particle jets reconstructed by the anti- algorithm with resolution parameter in the transverse-momentum interval . The soft drop and dynamical grooming algorithms are used to identify high transverse momentum splittings in the jet shower. Comparison of measurements in PbPb and pp collisions shows medium-induced narrowing, corresponding to yield suppression of high- splittings, in contrast to the expectation of yield enhancement due to quasi-particle scattering. The measurements are compared to theoretical model calculations incorporating jet quenching, both with and without quasi-particle scattering effects. These measurements provide new insight into the underlying mechanisms and theoretical modeling of jet quenching
First measurement of and production in proton--proton collisions at TeV at the LHC
No full textInternational audienceThe production yields of the orbitally excited charm-strange mesons and were measured for the first time in proton--proton (pp) collisions at a center-of-mass energy of TeV with the ALICE experiment at the LHC. The and mesons were measured at midrapidity () in minimum-bias and high-multiplicity pp collisions in the transverse-momentum interval GeV/. Their production yields relative to the ground-state yield were found to be compatible between minimum-bias and high-multiplicity collisions, as well as with previous measurements in and collisions. The measured and yield ratios are described by statistical hadronization models and can be used to tune the parameters governing the production of excited charm-strange hadrons in Monte Carlo generators, such as PYTHIA 8
Finite-temperature effects in hot axion production
No full textInternational audienceThe QCD axion has long been a subject of both theoretical and experimental interest due to being an elegant solution to the strong CP problem. It was also realized that axions can contribute significantly to the energy density of the Universe as dark radiation, that is a population of ultra-relativistic (or "hot") axions thermally produced in the early Universe by interacting with the Standard Model (SM) plasma.Today, one of the ways to constrain the axion-SM interactions is to compare the theoretically predicted axion contribution to the effective number of neutrinos with measurements obtained by experiments like Planck. The perspective of the next generation of experiments like the future CMB-S4 motivates newer, more precise determinations of thermal axion production.In this talk I will present recently obtained results on that matter, in the Kim-Shifman-Vainshtein-Zakharov (KSVZ) model where the axion couples only to gluons. The most important step in computations of the thermal production rate, as well as the main source of theory uncertainty, is the implementation of collective effects due to the medium. Those are essential to cure would-be divergences caused by the exchange of "soft" gluons in the t channel.I present two new computation schemes for determining the production rate and compare them to ones in the literature. Those new schemes solve or improve upon issues of production rate negativity and gauge dependence that can arise in the existing computation schemes. I also discuss how all considered computation schemes behave differently in the case of soft axion momentum and how this contributes to the uncertainty on the theoretical computation. Finally, I show results for quantities of phenomenological interest, like the aforementioned contribution to the effective number of neutrinos. I find that the theoretical contribution is in the ballpark of 0.032, with the error due to the computation scheme choice being around 0.002 at most.As an outlook, I will also touch on the automated techniques that were used in the research that was presented, and offer some perspectives as to how they could be extended to automate the entire production rate computation.The results presented in this talk were obtained in 2404.06113, written by myself and Jacopo Ghiglieri