A5081486569- Nuclear physics research studies
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Particle accelerators and beam dynamics
- Muon and positron interactions and applications
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Chemical Physics Studies
- Nuclear reactor physics and engineering
- Quantum Chromodynamics and Particle Interactions
- X-ray Spectroscopy and Fluorescence Analysis
- Particle physics theoretical and experimental studies
- Atomic and Subatomic Physics Research
- Superconducting and THz Device Technology
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Physics of Superconductivity and Magnetism
- Rare-earth and actinide compounds
- Radiation Detection and Scintillator Technologies
- Radioactive Decay and Measurement Techniques
- Scientific Measurement and Uncertainty Evaluation
- Radiation Therapy and Dosimetry
- Quantum, superfluid, helium dynamics
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
Laboratoire Kastler Brossel
2019-2025
Collège de France
2020-2025
Sorbonne Université
2020-2024
Centre National de la Recherche Scientifique
2020-2024
Université Paris Sciences et Lettres
2020-2024
CEA Paris-Saclay
2016-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2016-2024
École Normale Supérieure - PSL
2020-2024
Institut de Recherche sur les Lois Fondamentales de l'Univers
2016-2024
Université Paris-Saclay
2017-2024
We propose an experiment to measure the nuclear charge radii of light elements with up 20~times higher accuracy. These are essential both for understanding physics at low energies, and experimental theoretical applications in simple atomic systems. Such comparisons advance bound-state quantum electrodynamics useful searching new beyond Standard Model. The energy levels muonic atoms highly susceptible structure, especially mean square radius. lightest nuclei (with number, $Z=1,2$) have been...
Abstract Quantum electrodynamics (QED), the quantum field theory that describes interaction between light and matter, is commonly regarded as best-tested in modern physics. However, this claim mostly based on extremely precise studies performed domain of relatively low strengths atoms ions 1–6 . In realm very strong electromagnetic fields such heaviest highly charged (with nuclear charge Z ≫ 1), QED calculations enter a qualitatively different, non-perturbative regime. Yet, corresponding...
Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a $^{54}\mathrm{Ca}$ beam striking on liquid hydrogen target at $\ensuremath{\sim}200\text{ }\text{ }\mathrm{MeV}/u$. A significantly larger section to the ${p}_{3/2}$ state compared ${f}_{5/2}$ observed in excitation of $^{53}\mathrm{Ca}$ provides direct evidence nature $N=34$ shell closure. This finding corroborates arising new closure neutron-rich calcium isotopes. The...
The first $\ensuremath{\gamma}$-ray spectroscopy of $^{52}\mathrm{Ar}$, with the neutron number $N=34$, was measured using $^{53}\mathrm{K}(p,2p)$ one-proton removal reaction at $\ensuremath{\sim}210\text{ }\text{ }\mathrm{MeV}/\mathrm{u}$ RIBF facility. ${2}_{1}^{+}$ excitation energy is found 1656(18) keV, highest among Ar isotopes $N>20$. This result experimental signature persistence $N=34$ subshell closure beyond $^{54}\mathrm{Ca}$, i.e., below magic proton $Z=20$. Shell-model...
The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen ( \mu <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>μ</mml:mi></mml:math> p) with 1 ppm accuracy by means pulsed laser spectroscopy to determine two-photon-exchange contribution 2\times10^{-4}...
The first measurement of the low-lying states neutron-rich ^{110}Zr and ^{112}Mo was performed via in-beam γ-ray spectroscopy after one proton removal on hydrogen at ∼200 MeV/nucleon. 2_{1}^{+} excitation energies were found 185(11) keV in ^{110}Zr, 235(7) ^{112}Mo, while R_{42}=E(4_{1}^{+})/E(2_{1}^{+}) ratios are 3.1(2), close to rigid rotor value, 2.7(1), respectively. These results compared modern energy density functional based configuration mixing models using Gogny Skyrme effective...
We report on the first γ-ray spectroscopy of low-lying states in neutron-rich 98,100Kr isotopes obtained from 99,101Rb(p,2p) reactions at ∼220 MeV/nucleon. A reduction 2+1 state energies beyond N=60 demonstrates a significant increase deformation, shifted neutron number compared to sharper transition observed strontium and zirconium isotopes. State-of-the-art beyond-mean-field calculations using Gogny D1S interaction predict level good agreement with experimental results. The identification...
Excited states in the $N=40$ isotone $^{62}$Ti were populated via $^{63}$V$(p,2p)$$^{62}$Ti reaction at $\sim$200~MeV/u Radioactive Isotope Beam Factory and studied using $γ$-ray spectroscopy. The energies of $2^+_1 \rightarrow 0^{+}_{\mathrm{gs}}$ $4^+_1 2^+_1$ transitions, observed here for first time, indicate a deformed ground state. These are increased compared to neighboring $^{64}$Cr $^{66}$Fe isotones, suggesting small decrease quadrupole collectivity. present measurement is well...
We report on the first γ-ray spectroscopy of 51,53K produced via 52,54Ca(p,2p) reactions at ∼250 MeV/nucleon. Unambiguous final-state angular-momentum assignments were achieved for beam intensities down to few particles per second by using a new technique based reaction vertex tracking combined with thick liquid-hydrogen target. Through and exclusive parallel momentum distribution analysis, 3/2+ ground states 1/2+ excited in established quantifying natural ordering 1d3/2 2s1/2 proton-hole...
We explore the description of bound $^{19}$B isotope in terms a $^{17}$B+n+n three-body system where two-body subsystems $^{17}$B+n and neutron-neutron (nn) have virtual states close to continuum. Dimensionless scaling functions for root-mean-square (rms) radii are defined studied different parameters neutron-core potential considering three models interaction. The rooted on universal behavior systems Efimov limit depend only dimensionless quantities formed by two-neutron separation energies...
The x-ray spectroscopy of the muonic atom has attracted atomic, nuclear, and particle physicists since its discovery. properties a atom, such as binding energy or atomic radius, are different from an ordinary because difference in mass between muon electron. Our collaboration employed superconductor transition-edge sensor (TES) microcalorimeters for atom. Thanks to recent detector development, 44-keV lines Ar, which is important precision test bound-state quantum electrodynamics, 76-keV Si,...
Detailed comparisons between theory and experiment for quantum electrodynamics (QED) effects in He-like ions have been performed the literature to search hints of new physics. Different frequentist statistical analyses existing atomic transition energy data shown contradictory conclusions as presence possible deviations from predictions. We present here an approach using Bayesian statistics which allows assign quantitative probabilities different deviation models $Z = 5$ 92. Potential beyond...
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 low-energy antiproton beam provided ELENA ring at CERN, gaseous targets will be used for creation atoms, measurement transitions between circular Rydberg states conducted up two orders magnitude improved accuracy over previous...
Data on the structure of sulphur isotopes close to neutron drip-line are rather scarce. The excited states very neutron-rich \(^{46}\)S and \(^{47}\)S nuclei have been investigated by in-beam gamma-ray spectroscopy at Radioactive Isotope Beam Factory RIKEN Nishina Center. After multi-nucleon knockout reactions liquid-hydrogen MINOS target, \(2^{+}_{1}\rightarrow 0^{+}_{1}\) gamma transition \(^{46}\)S, already reported in literature, has confirmed. Additionally, two new rays assigned this...
The rapid neutron capture process (r-process) is thought to be responsible for the creation of more than half all elements beyond iron. scientific challenges understanding origin heavy iron lie in both uncertainties associated with astrophysical conditions that are needed allow an r-process occur and a vast lack knowledge about properties nuclei far from stability. There great global competition access measure most exotic existing facilities can reach, while simultaneously building new,...
$\ensuremath{\gamma}$-ray transitions between low-spin states of the neutron-rich $^{84,86,88}\mathrm{Ge}$ were measured by means in-flight spectroscopy at 270 MeV/u. Excited ${6}_{1}^{+},\phantom{\rule{0.16em}{0ex}}{4}_{1,2}^{+}$, and ${2}_{1,2}^{+}$ $^{84,86}\mathrm{Ge}$ ${4}_{1}^{+}$ $^{88}\mathrm{Ge}$ observed. Furthermore, a candidate for ${3}_{1}^{+}$ state $^{86}\mathrm{Ge}$ was identified. This plays key role in discussion ground-state triaxiality $^{86}\mathrm{Ge}$, along with other...
The one-neutron knockout from ^{52}Ca in inverse kinematics onto a proton target was performed at ∼230 MeV/nucleon combined with prompt γ spectroscopy. Exclusive quasifree scattering cross sections to bound states ^{51}Ca and the momentum distributions corresponding removal of 1f_{7/2} 2p_{3/2} neutrons were measured. sections, interpreted within distorted-wave impulse approximation reaction framework, are consistent shell closure neutron number N=32, found as strong N=28 N=34 Ca isotopes...
Neutron-rich Se88,90,92,94 isotopes were studied via in-beam γ-ray spectroscopy after nucleon removal reactions at intermediate energies the Radioactive Isotope Beam Factory. Based on γ−γ coincidence analysis, low-lying excitation level schemes are proposed for these nuclei, including 21+, 41+ states and 22+ remarkably low energies. The states, along with other features, indicate triaxiality in nuclei. experimental results good overall agreement self-consistent beyond-mean-field calculations...
We report on the measurement of new low-lying states in neutron-rich 81,82,83,84Zn nuclei via in-beam γ-ray spectroscopy. These include 41+→21+ transition 82Zn, 21+→0g.s.+ and transitions 84Zn, 81,83Zn were observed for first time. The reduced E(21+) energies increased E(41+)/E(2+1) ratios at N=52, 54 compared to those 80Zn attest that magicity is confined neutron number N=50 only. deduced level schemes are three state-of-the-art shell model calculations a good agreement with all...
Neutrons produced by the carbon fusion reaction $^{12}\mathrm{C}(^{12}\mathrm{C},n)^{23}\mathrm{Mg}$ play an important role in stellar nucleosynthesis. However, past studies have shown large discrepancies between experimental data and theory, leading to uncertain cross section extrapolation at astrophysical energies. We present first direct measurement that extends deep into energy range along with a new improved technique based on from mirror...
Precision study of few-electron, high-$Z$ ions is a privileged field for probing high-field, bound-state quantum electrodynamics (BSQED). However, the accuracy such tests plagued by nuclear uncertainties, which are often larger than BSQED effects under investigation. We propose an alternative method with exotic atoms and show that transitions may be found between circular Rydberg states where contributions vanishing while remain large. When probed newly available sensing detectors, these...
We observed electronic K x rays emitted from muonic iron atoms using superconducting transition-edge sensor microcalorimeters. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile characteristic Kα and Kβ together with hypersatellite Khα around 6 keV. This signature reflects time-dependent screening nuclear charge by negative muon L-shell electrons, accompanied electron side feeding. Assisted a simulation, these data clearly reveal K- hole production...
To test bound-state quantum electrodynamics (BSQED) in the strong-field regime, we have performed high precision x-ray spectroscopy of $5g--4f$ and $5f--\text{ }4d$ transitions (BSQED contribution 2.4 5.2 eV, respectively) muonic neon atoms low-pressure gas phase without bound electrons. Muonic been recently proposed as an alternative to few-electron high-$Z$ ions for BSQED tests by focusing on circular Rydberg states where nuclear contributions are negligibly small. We determined...