The 2p→1s transition energy in muonic ^9Be was measured using a metallic magnetic calorimeter, resulting in E_2p→ 1s=33 391.48(34)eV. The result is 30 times more precise than the previous best measurement and enables the extraction of the corresponding nuclear charge radius r_c(^9Be)=2.5506(51)fm. It is 2.4 times more precise than the commonly used value based on electron scattering and differs from it by 2.3 times the combined uncertainties. This measurement represents the first determination of a nuclear charge radius using muonic x-ray spectroscopy with microcalorimeters.

In this work, we have investigated the evolution of satellite intensity near the ionization threshold for Cu K-shell transitions through theoretical methods. Employing standard state-of-the-art ab initio methods, we have calculated all Cu K-shell transitions and simulated the full Kα_1 and Kα_2 spectrum where all transition parameters, as well as shake probabilities were determined theoretically. Through these calculations we show that standard state-of-the-art ab initio methods achieve good agreement with experiment and enable us to simulate the intensity evolution near ionization thresholds within a good margin of error. Below-threshold satellite intensity was found to originate from resonant 1s→3d and 1s→4p excitations in Cu(I) and Cu(II) oxide phases respectively, which were included in our simulations.

antiProtonic Atom X-ray (PAX) spectroscopy is an experiment that aims to test strong-field quantum electrodynamics (QED) effects by performing high-precision X-ray spectroscopy of antiprotonic atoms. PAX will use a low-energy antiproton beam provided by the Extra Low ENergy Antiproton (ELENA) ring at the European Organization for Nuclear Research (CERN) to create antiprotonic atoms. A superconducting transition-edge sensor (TES) spectrometer will be used to measure the energy of transitions between circular Rydberg states in these atoms. The energy range of interest for the experiment spans 50 keV to 250 keV, and the desired precision for measuring the centroids of the emission lines is 10(-5). The spectrometer for PAX is intended to have four 96-pixel TES arrays and will be read out with a microwave superconducting quantum interference device (SQUID) multiplexer. As a step toward building the full instrument, we built a scaled-down version of the spectrometer that was installed at the TEst Line for Machine And Antimatter eXperiments (TELMAX) facility at ELENA in April 2025. The purpose of this deployment was to make an observation of X-ray emission by antiprotonic atoms and to better understand the effect of the pionic charged particle background due to antiproton annihilation on the performance of the TES array. This pilot spectrometer had an array of 60 TES pixels in a compact adiabatic demagnetization refrigerator cryostat. The sensors were read out with a microwave SQUID multiplexer. Each pixel consisted of a molybdenum/gold bilayer TES with a coplanar gold "landing pad" for a bulk tin absorber that was attached by an epoxy joint. We discuss the design of the TES pixels, the microwave SQUID readout, and the cryogenic platform. Finally, we present calibration data obtained at TELMAX using radioactive sources to assess the performance of the spectrometer in the antiproton beam-off condition.

PAX (antiProtonic Atom X-ray spectroscopy) is a new experiment with the aim to test strong-field quantum electrodynamics (QED) effects by performing high-precision x-ray spectroscopy of antiprotonic atoms. By utilizing advanced microcalorimeter detection techniques and a low-energy antiproton beam provided by the ELENA ring at CERN, gaseous targets will be used for the creation of antiprotonic atoms, and the measurement of transitions between circular Rydberg states will be conducted with up to two orders of magnitude improved accuracy over previous studies using high-purity germanium detectors. Our approach eliminates the longstanding issue of nuclear uncertainties that have hindered prior studies using highly charged ions, thus enabling direct and purely QED-focused measurements. By precisely probing atomic systems with electric fields up to two orders of magnitude above the Schwinger limit, PAX will test vacuum polarization and second-order QED corrections, opening new frontiers in fundamental physics and uncovering potential pathways to physics beyond the Standard Model.

Detailed comparisons between theory and experiment for quantum electrodynamics (QED) effects in He-like ions have been performed in the literature to search for hints of new physics. Different frequentist statistical analyses of the existing atomic transition energy data have shown contradictory conclusions as to the presence of possible deviations from the theory predictions. We present here an approach using Bayesian statistics to assign quantitative probabilities to the different deviation models from theory for He-like ions for Z = 5-92. Potential deviations beyond the standard model or higher-order QED effects are modeled with f (Z) proportional to Zk functions. Considering the currently available data, no significant difference between theory and experiment is found, and we show that recent experiments have reduced the possible deviations previously observed in the literature. Using past measurements and a weighted average on the different deviation models, we estimate the accuracy required for future measurements to investigate possible anomalies.

Background: Systemic lupus erythematosus (SLE) affects mainly women of child-bearing age, and is associated with worse pregnancy and disease outcomes during pregnancy. Physiologically, pregnancy is associated with an immunotolerance state, and in other rheumatic diseases such as rheumatoid arthritis (RA) pregnancy is associated with a lower disease activity. The molecular mechanisms underlying immune differences between healthy, RA and SLE pregnancies are largely unknown. Objectives: To prospectively study the circulating monocyte mRNA and miRNA from healthy, RA and SLE women before, during and immediately after pregnancy. Methods: Patients with RA or SLE and age-matched controls were included in the study. EDTA-anticoagulated blood was drawn within 3 months before pregnancy, at the time of positive pregnancy test, month 3 and 6 of pregnancy, during delivery and 1 month and 3 of post-partum. Monocytes were sorted using CD14 magnetic sorting (Miltenyi). Total RNAs were extracted with a commercial kit (Qiagen) and the transcriptome obtained using paired-end sequencing with a new generation sequencer SOLID 5500 (Life technologies). Sequencing data was processed using the nf-core/rnaseq pipeline, version 3.10.1. Within this pipeline, STAR was used for sequence alignment, while Salmon was used for RNA quantification, resulting in an expression matrix. For miRNAs, mirdeep2 was used to generate the expression matrix. In subsequent steps, DESeq2 was used to study differential expression. For each condition (SLE, RA or control), visits in chronological order were considered as a continuous variable on which transcriptional patterns were explored. In addition, the patient ID was used as a covariate to control for individual variability in gene expression profiles. For enrichment analyses and regulator predictions, Ingenuity Pathway Analysis (IPA) software was used to decipher the expression variations observed. To link miRNAs and downstream mRNA targets, a correlation analysis was performed between mRNA and miRNA signal of the same patients. A miRNA was predicted to negatively regulate a mRNA if it was negatively correlated with that transcript across samples, and predicted as such by miRTarBase. Results: Six patients with SLE, four with RA and five healthy donors were included. During the progression of RA pregnancies, the pathway enrichments highly correlated with the ones from healthy pregnancies (r = 0.82, p = 3.28 x10-6, Figure 1A). Conversely, the enrichments from SLE pregnancies did not correlate with healthy ones (r = 0.02, p = 0.94, Figure 1B), suggesting that SLE pregnancies have a distinct transcriptomic signature. Using pathway analysis we identified a downregulation of the interferon gamma, interleukin 1 and CD40L/CD40 pathways in both healthy and RA pregnancies during the progression of pregnancy. During SLE pregnancies, we identified an upregulation of pathways of interferon gamma, Interleukins 1, 6 and 8 and Tumor Necrosis factor. The upregulation of these inflammatory pathways remained significant after excluding visits with a clinical flare.In contrast to healthy donors and RA patients, SLE patients were characterized by a significant downregulation of miRNAs 106a-5p and 148b-5p (adjusted p-value < 0.05) predicted to control cytokine-mediated signaling pathway and neutrophils activation/degranulation (adjusted p-values < 0.001 and < 0.01, respectively). Conclusion: We identify that SLE pregnancies have a distinct monocyte transcriptomic signature which differs from healthy and RA pregnancies, that accompany increased risk of disease flares and adverse pregnancy events. Furthermore, our data suggest that miRNA may participate to this pro-inflammatory signature, which opens the way for a better understanding of SLE pregnancy and the development of biomarkers of adverse pregnancy events. REFERENCES: NIL. Acknowledgements: This project was founded by the l‘ANR PRCI “SPIRALE“ and by l‘ITI Transplantex. The DRCI of the HUS for promoting the study. MS is supported by ATIP-AVENIR, INSERM, Fondation Bettencourt-Schueller, FOREUM Early Career Grant and Fondation Arthritis. Disclosure of Interests: Eloi Schmauch: None declared, Philippe Georgel: None declared, Raphael Carapito: None declared, Angélique Pichot: None declared, Ghada Alsaleh: None declared, Nicodème Paul: None declared, Anne Molitor: None declared, Catherine Mutter: None declared, Jacques-Eric Gottenberg: None declared, Renaud Felten: None declared, Séiamak Bahram: None declared, Jean SIBILIA: None declared, Marc SCHERLINGER Amgen, AstraZeneca, Biogen, BMS, Fresenius Kabi, Galapagos, GSK, Nordic Pharma, Novartis, Sandoz., Amgen, AstraZeneca, Biogen, BMS, Fresenius Kabi, Galapagos, GSK, Nordic Pharma, Novartis, Sandoz.Figure 1correlation of enriched pathways between healthy and RA (A) and healthy and SLE (B) pregnancies.

A highly charged muonic ion is a unique few-body atomic system where a negatively charged muon and a few electrons are simultaneously bound to a single nucleus. We report the first state-selective observation of highly charged muonic Ar (mu Ar) by electronic K x-ray spectroscopy using an array of transition-edge sensor microcalorimeters. The high-precision K x-ray spectra provide a clear signature of the presence of muonic atoms with one, two, and three electrons, i.e., H-like, He-like, and Li-like mu Ar. With the aid of theoretical calculations, we confirmed that the peak positions are consistent with the x-ray energies from highly charged Cl ions, and the intensities reflect deexcitation dynamics of highly charged mu Ar.

The X-ray spectroscopy of the muonic atom has attracted atomic, nuclear, and particle physicists since its discovery. The properties of a muonic atom, such as its binding energy or atomic radius, are different from an ordinary atom because of the difference in the mass between the muon and electron. Our collaboration has employed superconductor transition-edge sensor (TES) microcalorimeters for the x-ray spectroscopy of the muonic atom. Thanks to the recent detector development, the 44-keV lines from muonic Ar, which is important for the precision test of bound-state quantum electrodynamics, and the 76-keV lines from muonic Si, which is of interest from the viewpoint of the measurement of nuclear radii, have been reached by the dynamic range of the state-of-art TES microcalorimeters. An accelerator facility that can produce a high-intensity muon beam is necessary for such spectroscopic experiments. We performed a commissioning experiment of the hard x-ray and gamma-ray TES microcalorimeter at the J-PARC MLF MUSE muon beam line. The energy resolution, gain stability, and performance of timing selection of the pulses were evaluated in the environment of a large-scale accelerator facility.

The QUARTET collaboration aims to significantly improve the precision of the absolute nuclear charge radii of light nuclei from Li to Ne by using an array of metallic magnetic calorimeters to perform high-precision X-ray spectroscopy of low-lying states in muonic atoms. A proof-of-principle measurement with lithium, beryllium and boron is planned for fall 2023 at the Paul Scherrer Institute. We discuss the performance achieved with the maXs-30 detector module to be used. To place the detector close to the target chamber where the muon beam will impact the material under study, we have developed a new dilution refrigerator sidearm. We further discuss the expected efficiency given the transparency of the X-ray windows and the quantum efficiency of the detector. The expected muonic X-ray rate combined with the high resolving power and detection efficiency of the detector suggest that QUARTET will be able to study the de-excitation of light muonic atoms at an unprecedented level, increasing the relative energy resolution by up to a factor of 20 compared to conventional detector techniques.

The N = 34 isotope Sc-55 has been investigated using in-beam gamma-ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory. Spectra from the direct (p, pn) reaction as well as indirect reaction channels have been investigated. gamma rays with energies 496(10), 570(12), 682(14), 1510(30), 1780(36), 2345(57) and 2470(50) keV have been observed. A level scheme was constructed based on gamma gamma coincidence analysis and relative intensities. The results have been compared to the level scheme already reported in literature, as well as to large-scale shell model calculations in the sd - pf model space. A new level at 1510keV, decaying directly to the ground state, has been proposed and spin-parity J(pi) = 7/2(-) was tentatively assigned. The effect of including the nu g(9/2) orbital is discussed. It can be concluded that the main low-energy properties of Sc-55 seem to be included in the original sd - pf model space.

The first spectroscopy of 52K was investigated via in-beam gamma-ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory after one-proton and one-neutron knockout from 53 Ca and 53K beams impinging on a 15-cm liquid hydrogen target at approximate to 230 MeV/nucleon. The energy level scheme of 52K was built using single gamma and gamma-gamma coincidence spectra. The spins and parities of the excited states were established based on momentum distributions of the fragment after the knockout reaction and based on exclusive cross sections. The results were compared to state-of-the-art shell model calculations with the SDPF-Umod interaction and ab initio in- medium similarity renormalization group calculations with chiral effective field theory nucleon-nucleon and three-nucleon forces.

The shell closure at N = 32 has been investigated by a first spectroscopy of the N = 31 nucleus 49Ar at the Radioactive Isotope Beam Factory. Using the 50Ar(p, pn) reaction channel in inverse kinematics, 50Ar projectiles at 217 MeV/nucleon impinged on a 150 mm long liquid hydrogen target, part of the MINOS device. Prompt deexcitation gamma rays were measured with the NaI(Tl) array DALI2+. Reaction products were analyzed with the SAMURAI spectrometer, which allowed the measurement of the momentum distributions and angular momentum transfer. Data were compared to state-of-the-art theoretical predictions, including shell -model, energy -density functional, and ab initio calculations. An onset of collectivity is suggested besides the spherical configuration typical of a closed shell nucleus, such as for 52Ca.

Quantum electrodynamics (QED), the quantum field theory that describes the interaction between light and matter, is commonly regarded as the best-tested quantum theory in modern physics. However, this claim is mostly based on extremely precise studies performed in the domain of relatively low field strengths and light atoms and ions 1 – 6 . In the realm of very strong electromagnetic fields such as in the heaviest highly charged ions (with nuclear charge Z ≫ 1), QED calculations enter a qualitatively different, non-perturbative regime. Yet, the corresponding experimental studies are very challenging, and theoretical predictions are only partially tested. Here we present an experiment sensitive to higher-order QED effects and electron–electron interactions in the high- Z regime. This is achieved by using a multi-reference method based on Doppler-tuned X-ray emission from stored relativistic uranium ions with different charge states. The energy of the 1 s 1/2 2 p 3/2 J = 2 → 1 s 1/2 2 s 1/2 J = 1 intrashell transition in the heaviest two-electron ion (U 90+ ) is obtained with an accuracy of 37 ppm. Furthermore, a comparison of uranium ions with different numbers of bound electrons enables us to disentangle and to test separately the one-electron higher-order QED effects and the bound electron–electron interaction terms without the uncertainty related to the nuclear radius. Moreover, our experimental result can discriminate between several state-of-the-art theoretical approaches and provides an important benchmark for calculations in the strong-field domain.

We have measured several 2p → 1s transition energies in core-excited boron-like ions of sulfur and argon. The measurements are reference-free, with an accuracy of a few parts per million. The x-rays were produced by the plasma of an electron cyclotron resonance ion source and measured with a double-crystal x-ray spectrometer. The precision obtained for the measured 1s 2s^2 2p^2 J - 1s^2 2s^2 2p J' lines is ≈ 3.8 ppm for sulfur and ≈ 2.5 ppm for argon. The line energies are compared to relativistic atomic structure calculations performed with the mdfgme multi-configuration Dirac–Fock code. This comparison is used for line identification and tests the theoretical methods, which are in agreement with the experimental data up to 49 meV . The theoretical calculations have been extended to B, C^+ , Si^9+ , Cr^19+ and Fe^21+ , which were the only B-like ions where such transitions were measured up to now.

The calcium isotopes are an ideal system to investigate the evolution of shell structure and magic numbers. Although the properties of surface nucleons in calcium have been well studied, probing the structure of deeply bound nucleons remains a challenge. Here, we report on the first measurement of unbound states in 53Ca and 55Ca, populated from 54,56Ca(p,pn) reactions at a beam energy of around 216 MeV/nucleon at the RIKEN Radioactive Isotopes Beam Factory. The resonance properties, partial cross sections, and momentum distributions of these unbound states were analyzed. Orbital angular momentum l assignments were extracted from momentum distributions based on calculations using the distorted wave impulse approximation (DWIA) reaction model. The resonances at excitation energies of 5516(41)keV in 53Ca and 6000(250)keV in 55Ca indicate a significant l =3 component, providing the first experimental evidence for the ν0f7/2 single-particle strength of unbound hole states in the neutron-rich Ca isotopes. The observed excitation energies and cross-sections point towards extremely localized and well separated strength distributions, with some fragmentation for the ν0f7/2 orbital in 55Ca. These results are in good agreement with predictions from shell-model calculations using the effective GXPF1Bs interaction and ab initio calculations and diverge markedly from the experimental distributions in the nickel isotones at Z=28.

We, the QUARTET Collaboration, propose an experiment to measure the nuclear charge radii of light elements with up to 20 times higher accuracy. These are essential both for understanding nuclear physics at low energies, and for experimental and theoretical applications in simple atomic systems. Such comparisons advance the understanding of bound-state quantum electrodynamics and are useful for searching for new physics beyond the Standard Model. The energy levels of muonic atoms are highly susceptible to nuclear structure, especially to the mean square charge radius. The radii of the lightest nuclei (with the atomic number, Z=1,2) have been determined with high accuracy using laser spectroscopy in muonic atoms, while those of medium mass and above were determined using X-ray spectroscopy with semiconductor detectors. In this communication, we present a new experiment, aiming to obtain precision measurements of the radii of light nuclei 3≤Z≤10 using single-photon energy measurements with cryogenic microcalorimeters; a quantum-sensing technology capable of high efficiency with outstanding resolution for low-energy X-rays.

We report on the first production of an antihydrogen beam by charge exchange of 6.1 keV antiprotons with a cloud of positronium in the GBAR experiment at CERN. The antiproton beam was delivered by the AD/ELENA facility. The positronium target was produced from a positron beam itself obtained from an electron linear accelerator. We observe an excess over background indicating antihydrogen production with a significance of 3-4 standard deviations.

Primary antiphospholipid syndrome is characterized by thrombosis and autoantibodies directed against phospholipids or associated proteins. The genetic etiology of PAPS remains unknown. We enrolled 21 patients with thromboembolic events associated to lupus anticoagulant, anticardiolipin and anti β2 glycoprotein1 autoantibodies. We performed whole exome sequencing and a systematic variant-based analysis in genes associated with thrombosis, in candidate genes previously associated with APS or inborn errors of immunity. Data were compared to public databases and to a control cohort of 873 non-autoimmune patients. Variants were identified following a state-of-the-art pipeline. Enrichment analysis was performed by comparing with the control cohort. We found an absence of significant HLA bias and genetic heterogeneity in these patients, including when testing combinations of rare variants in genes encoding for proteins involved in thrombosis and of variants in genes linked with inborn errors of immunity. These results provide evidence of genetic heterogeneity in PAPS, even in a homogenous series of triple positive patients. At the individual scale, a combination of variants may participate to the breakdown of B cell tolerance and to the vessel damage.

La grossesse est une situation physiologique caractérisée par une phénotype tolérogène du système immunitaire. Chez les patientes atteintes de lupus érythémateux systémique (LES), la grossesse est associée à un risque accru de poussée, tandis que dans la polyarthrite rhumatoïde (PR), la grossesse est associée à une plus faible activité inflammatoire. Cependant, les déterminants moléculaires de ces différences sont inconnus. L’objectif de cette étude était d’évaluer prospectivement la signature transcriptomique et microRNA des monocytes circulants durant des grossesses de donneuses saines, de PR ou de LES. Des donneuses enceintes saines ou atteintes de PR ou de LES étaient inclues en préconceptionnel et suivies prospectivement durant la grossesse jusqu’à 3 mois post-partum, pour 7 visites/prélèvements au total. À chaque visite, les monocytes étaient triés à partir du sang total par un tri magnétique CD14 (Miltenyi) et l’ARN total était extrait par un kit commercial (Qiagen). Le transcriptome était étudié par RNAsequencing par le biais d’un séquenceur haut débit SOLID 5500 (Life technologies) avec un séquençage « paired end ». Les données de séquençage étaient traitées à l’aide du pipeline nf-core/rnaseq, version 3.10.1. Au sein de ce pipeline, STAR a été employé pour l’alignement des séquences, tandis que Salmon était utilisé pour la quantification des ARN, aboutissant à une matrice d’expression. Pour les miRNA, mirdeep2 était utilisé pour générer la matrice d’expression. Dans les étapes ultérieures, DESeq2 a été employé pour l’étude de l’expression différentielle. Pour les analyses d’enrichissement et les prédictions des régulateurs, le logiciel Ingenuity Pathway Analysis a été employé afin de décrypter les variations d’expression constatées. Les p-value étaient corrigées par la méthode de Benjamini-Hochberg. Six patientes atteintes de LES, quatre de PR et cinq donneuses saines étaient inclues. Dans la grossesse physiologique, la transcriptomique monocytaire était caractérisée par une signature anti-inflammatoire (diminution significative des voies TNFα et CD40L, p < 10-11 et p < 10-10, respectivement). De manière similaire, les grossesses de patientes atteintes de PR présentaient une signature transcriptomique anti-inflammatoire diminution significative des voies TNFα, IL1ß, p < 10-7 et p < 10-8, respectivement). En comparaison, les patientes atteints de LES présentaient une signature transcriptomique pro-inflammatoire durant la grossesse activation significative des voies IL1ß, IFNγ, p < 10-12 et p < 10-10, respectivement). Cette signature pro-inflammatoire de la grossesse lupique persistait après l’exclusion de la patiente ayant présenté une poussée durant la grossesse. L’activité du LES (évaluée par le SLEDAI) était positivement corrélée à une signature TGFß et IFNγ (p < 10-10 et p < 10-8, respectivement) tandis que l’activité de la PR (évaluée par le DAS28-CRP) était positivement corrélée à une signature TNFα et IL-6 (p < 10-37 et p < 10-22, respectivement). L’analyse des données miRNA est en cours, et pourrait expliquer les différences transcriptomiques observées entre PR et LES. Il s’agit de la première étude évaluant prospectivement la signature transcriptomique et miRNA des monocytes dans les maladies immunomédiées. Les grossesses de LES présentent une signature transcriptomique diamétralement opposée à celles de PR ou de donneuses saines. Ces résultats pourraient permettre de comprendre l’origine des poussées durant les grossesses de LES, mais également de développer des biomarqueurs prédictifs de poussée durant la grossesse lupique.