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Constraints on the cosmic expansion history from GWTC-3
No full textMain paper: 30 pages, 15 figure, 7 tablesInternational audienceWe use 47 gravitational wave sources from the Third LIGO–Virgo–Kamioka Gravitational Wave Detector Gravitational Wave Transient Catalog (GWTC–3) to estimate the Hubble parameter H(z), including its current value, the Hubble constant H0. Each gravitational wave (GW) signal provides the luminosity distance to the source, and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z). The source mass distribution displays a peak around 34 M⊙, followed by a drop-off. Assuming this mass scale does not evolve with the redshift results in a H(z) measurement, yielding(68% credible interval) when combined with the H0 measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the H0 estimate from GWTC–1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value ofwith the galaxy catalog method, an improvement of 42% with respect to our GWTC–1 result and 20% with respect to recent H0 studies using GWTC–2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about H0) is the well-localized event GW190814
Improving Fission-product Decay Data for Reactor Applications: Part I -- Decay Heat
No full textInternational audienceEffort has been expended to assess the relative merits of undertaking further decay-data measurements of the main fission-product contributors to the decay heat of neutron-irradiated fissile fuel and related actinides by means of Total Absorption Gamma-ray Spectroscopy (TAGS/TAS) and Discrete Gamma-ray Spectroscopy (DGS). This review has been carried out following similar work performed under the auspices of OECD/WPEC-Subgroup 25 (2005-2007) and the International Atomic Energy Agency (2010, 2014), and various highly relevant TAGS measurements completed as a consequence of such assessments. We present our recommendations for new decay-data evaluations, along with possible requirements for total absorption and discrete high-resolution gamma-ray spectroscopy studies that cover approximately 120 fission products and various isomeric states
Modeling polonium complexes in solution
No full textInternational audiencePolonium is a heavy and rare element standing under the number 84 on the Periodic Table. It is a naturally occurring element, though its abundance is among the weakest ones. It is highly toxic, which hinders experimental studies aiming at revealing its properties. Nevertheless, polonium was used as a heat source in the space industry, as an alpha-emission source, or as a static eliminator, before cheaper and safer alternatives replaced it. It is also a famous poison, with currently no good enough antidote. A better understanding of its chemistry could potentially help in better detecting it and also characterizing its speciation in natural media and industry and also in designing better cure in the case of ingestion. However, the available quantities and the complex manipulation of this element make its characterization arduous. In this context, we perform quantum chemistry calculations to predict the properties of polonium species. In our project, we study polonium complexes in the gas phase and in solution. We consider its most stable oxidation state in solution, i.e. +IV. Following previous work [1,2], two families of complexes were first chosen for performing a methodological study in the gas phase. While the [Po(H2O)n]4+ (n = 1–9) series was selected to get fundamental knowledge of hydration, the chlorinated [PoClm]4–m (m = 1–8) complexes were studied because of experimental evidence for the formation of such species in solution. As an extension to a benchmark study in the gas phase on geometries and interaction energies, ground state bonding descriptors were obtained [3]. Therefore, information on coordination numbers and chemical bonding were both derived. Following the idea to connect with established experimental data, state-of-the-art excited-state calculations have been performed on two potentially occurring chlorinated complexes, revealing once more the difficulty of interpreting from scratch the few spectra that are available for polonium species. We thus emphasize the need for performing more calculations of predictive quality to unravel this enigmatic chemistry. References:[1] R. Ayala, J. M. Martinez, R. R. Pappalardo, A. Muñoz-Paez and E. Marcos Sánchez, J. Phys. Chem. B, 2008, 112, 5416–5422.[2] A. Stoanov, J. Champion and R. Maurice, Inorg. Chem., 2019, 58, 7036-7043.[3] N. Zhutova, F. Réal, V. Vallet and R. Maurice, Phys. Chem. Chem. Phys., 2022, 24, 26180-26189
Data-driven precision determination of the material budget in ALICE
No full textInternational audienceThe knowledge of the material budget with a high precision is fundamental for measurements of direct photon production using the photon conversion method due to its direct impact on the total systematic uncertainty. Moreover, it influences many aspects of the charged-particle reconstruction performance. In this article, two procedures to determine data-driven corrections to the material-budget description in ALICE simulation software are developed. One is based on the precise knowledge of the gas composition in the Time Projection Chamber. The other is based on the robustness of the ratio between the produced number of photons and charged particles, to a large extent due to the approximate isospin symmetry in the number of produced neutral and charged pions. Both methods are applied to ALICE data allowing for a reduction of the overall material budget systematic uncertainty from 4.5% down to 2.5%. Using these methods, a locally correct material budget is also achieved. The two proposed methods are generic and can be applied to any experiment in a similar fashion
Systematic dosimetric evaluation of risk of osteoradionecrosis (DERO): First results of dose reporting for preventing teeth osteoradionecrosis after head and neck irradiation
No full textInternational audiencePurpose: OsteoRadioNecrosis (ORN) is a late complication of radiation for head and neck cancer. Predicting ORN is a major challenge. We developed DERO (Dosimetric Evaluation of Risk of ORN), a semi-automatic tool which reports doses delivered to tooth-bearing sectors, to guide post-therapeutic dental care. We present the method and the first results of a 125-patient prospective cohort. Material and methods: Dosimetric data of patients treated with IMRT for head and neck cancer were prospectively segmented to the DERO algorithm. Four arches corresponding to 8-tooth sectors were semi-automatically generated. Thirty-two cylindrical Regions Of Interest (ROI) corresponding to each tooth and surrounding periodontium were created by linear interpolation. Mean doses (Dmean) of ROI were extracted and included in a database, along with data about primary tumor site, laterality and dose values from organs at risk. Dmean to tooth sectors were computed for molar sectors, (teeth X5 to X8) and anterior sectors (teeth X1 to X4). An individual dose map was generated and delivered to patients and dentists. Results: Dosimetric data from 125 patients treated with Tomotherapy® were prospectively collected and analyzed: 9 parotid tumors (PA), 41 Sub-Hyoid tumors (larynx, hypopharynx) (SH), 43 Oropharynx tumors (OR), 32 Oral Cavity tumors (OC). Irradiation was unilateral for 100% of PA tumors (9), 12% of OR tumors (5) and 47% of OC tumors (15). For unilateral cervical irradiation, Dmean in ipsilateral molar sectors was 54 Gy for OC tumors, 45 Gy for OR tumors, 20 Gy for PA tumors. For Oral Cavity bilateral irradiation, Dmean was high in all tooth sectors, 49 to 55 Gy. For SH tumors, Dmean in molar sectors was 27 Gy. A dose gradient of 10 to 20 Gy was observed between molar and anterior sectors whether radiation was uni or bilateral. Conclusion: Mandibular molar sectors of Oropharynx and Oral Cavity tumors were exposed to high Dmean of 40 to 50 Gy. On the other hand, tooth sectors received lower doses for SH radiation. The DERO tool guide post-radiation dental care with a personalized dosimetric cartography to patient. With data update and patient follow-up, we will be able to determine ORN risk after head and neck radiation
Light (anti)nuclei production in Pb-Pb collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn><mo> </mo><mi>TeV</mi></mrow></math>
No full textInternational audienceThe measurement of the production of deuterons, tritons and He3 and their antiparticles in Pb-Pb collisions at sNN=5.02TeV is presented in this article. The measurements are carried out at midrapidity (|y|< 0.5) as a function of collision centrality using the ALICE detector. The pT-integrated yields, the coalescence parameters and the ratios to protons and antiprotons are reported and compared with nucleosynthesis models. The comparison of these results in different collision systems at different center-of-mass collision energies reveals a suppression of nucleus production in small systems. In the Statistical Hadronisation Model framework, this can be explained by a small correlation volume where the baryon number is conserved, as already shown in previous fluctuation analyses. However, a different size of the correlation volume is required to describe the proton yields in the same data sets. The coalescence model can describe this suppression by the fact that the wave functions of the nuclei are large and the fireball size starts to become comparable and even much smaller than the actual nucleus at low multiplicities
First measurement of <math><msubsup><mi mathvariant="normal">Λ</mi><mrow><mi>c</mi></mrow><mo>+</mo></msubsup></math> production down to <math><mrow><msub><mi>p</mi><mi>T</mi></msub><mo>=</mo><mn>0</mn></mrow></math> in <math><mrow><mi>p</mi><mi>p</mi></mrow></math> and <math><mi>p</mi></math>-Pb collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV
No full textInternational audienceThe production of prompt Λc+ baryons has been measured at midrapidity in the transverse momentum interval 0<pT<1 GeV/c for the first time, in pp and p–Pb collisions at a center-of-mass energy per nucleon-nucleon collision sNN=5.02TeV. The measurement was performed in the decay channel Λc+→pKS0 by applying new decay reconstruction techniques using a Kalman-Filter vertexing algorithm and adopting a machine-learning approach for the candidate selection. The pT-integrated Λc+ production cross sections in both collision systems were determined and used along with the measured yields in Pb–Pb collisions to compute the pT-integrated nuclear modification factors RpPb and RAA of Λc+ baryons, which are compared to model calculations that consider nuclear modification of the parton distribution functions. The Λc+/D0 baryon-to-meson yield ratio is reported for pp and p–Pb collisions. Comparisons with models that include modified hadronization processes are presented, and the implications of the results on the understanding of charm hadronization in hadronic collisions are discussed. A significant (3.7σ) modification of the mean transverse momentum of Λc+ baryons is seen in p–Pb collisions with respect to pp collisions, while the pT-integrated Λc+/D0 yield ratio was found to be consistent between the two collision systems within the uncertainties
First observation of the cosmic ray shadow of the Moon and the Sun with KM3NeT/ORCA
No full textInternational audienceThis article reports the first observation of the Moon and the Sun shadows in the sky distribution of cosmic-ray induced muons measured by the KM3NeT/ORCA detector. The analysed data-taking period spans from February 2020 to November 2021, when the detector had 6 Detection Units deployed at the bottom of the Mediterranean Sea, each composed of 18 Digital Optical Modules. The shadows induced by the Moon and the Sun were detected at their nominal position with a statistical significance of 4.2 and 6.2, and an angular resolution of and , respectively, consistent with the prediction of from simulations. This early result confirms the effectiveness of the detector calibration, in time, position and orientation and the accuracy of the event direction reconstruction. This also demonstrates the performance and the competitiveness of the detector in terms of pointing accuracy and angular resolution
Study of terbium production from enriched Gd targets via the reaction Gd(d,2n)Tb
No full textInternational audienceThe terbium (Tb) family has attracted much attention in recent years thanks to the diagnostic and therapeutic applications of the quadruplet 149Tb, 152Tb, 155Tb and 161Tb. However, the scarce availability of Tb radioisotopes is one of the main reasons hindering its clinical applications. To increase its availability, this work proposes to use enriched gadolinium (Gd) targets to produce some Tb radioisotopes (149Tb, 152Tb, and 155Tb) via deuteron-induced reactions in cyclotrons. The production of the Auger and gamma emitter 155Tb was chosen as a case study because the 155Gd enrichment (92.8%) is the highest available from all Gd stable isotopes. The involved reaction is 155Gd(d,2n)155Tb. Using enriched thin Gd-containing targets, cross-sections of the reactions 155Gd(d,x)153,154,155,156Tb have been measured at the GIP ARRONAX cyclotron facility with a beam energy ranging from 8 MeV to 30 MeV. This measurement allows for estimating the production yield and the purity of 155Tb, and for determining the irradiation parameters for large production batches. A thick enriched 155Gd2O3 target has been then irradiated with an incident energy of 15.1 MeV and a beam current of 368 nA for 1 h. The production yield of 155Tb is 10.2 MBq/μA/h at End Of Bombardment (EOB) and the purity is 89% after 14 days of decay. These experimental values are consistent with estimation based on measured cross-sections. A comparison of the deuteron-induced and proton-induced production routes is also presented in this paper
Open Data from the Third Observing Run of LIGO, Virgo, KAGRA, and GEO
No full textInternational audienceThe global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages