A. Leredde
A5033425373- Atomic and Subatomic Physics Research
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Mass Spectrometry Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Laser-induced spectroscopy and plasma
- Radiation Detection and Scintillator Technologies
- Advanced Frequency and Time Standards
- Nuclear physics research studies
- Particle physics theoretical and experimental studies
- Ion-surface interactions and analysis
- Nuclear Physics and Applications
- Neutrino Physics Research
- Particle Detector Development and Performance
- Advanced MRI Techniques and Applications
- Spectroscopy and Quantum Chemical Studies
- Radioactive Decay and Measurement Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Quantum Information and Cryptography
- Quantum optics and atomic interactions
- Quantum Mechanics and Applications
- Atmospheric Ozone and Climate
- Quantum Chromodynamics and Particle Interactions
- Superconducting Materials and Applications
Université Grenoble Alpes
2018-2022
Centre National de la Recherche Scientifique
2010-2022
Institut National de Physique Nucléaire et de Physique des Particules
2010-2022
Institut polytechnique de Grenoble
2019-2022
Argonne National Laboratory
2014-2022
University of Sussex
2020
Laboratoire de Physique Subatomique et de Cosmologie
2019
École Nationale Supérieure d'Ingénieurs de Caen
2010-2018
Normandie Université
2018
Université de Caen Normandie
2010-2018
We present the result of an experiment to measure electric dipole moment (EDM) neutron at Paul Scherrer Institute using Ramsey's method separated oscillating magnetic fields with ultracold neutrons (UCN). Our measurement stands in long history EDM experiments probing physics violating time reversal invariance. The salient features this were use a Hg-199 co-magnetometer and array optically pumped cesium vapor magnetometers cancel correct for field changes. statistical analysis was performed...
It has been proposed that there could be a mirror copy of the standard model particles, restoring parity symmetry in weak interaction on global level. Oscillations between neutral particle, such as neutron, and its counterpart potentially answer various standing issues physics today. Astrophysical studies terrestrial experiments led by ultracold neutron storage measurements have investigated to mirror-neutron oscillations imposed constraints theoretical parameters. Recently, further analysis...
We present the design of a next-generation experiment, n2EDM, currently under construction at ultracold neutron source Paul Scherrer Institute (PSI) with aim carrying out high-precision search for an electric dipole moment neutron. The project builds on experience gained previous apparatus operated PSI until 2017, and is expected to deliver order magnitude better sensitivity provision further substantial improvements. An overview experimental method setup given, requirements are derived, its...
We measured kinetic energies of the fragment ions argon dimers multiply ionized by low-energy Ar(9+) collisions. For (Ar2)(4+) dissociation, asymmetric channel (Ar(3+) + Ar(+)) yield is found unexpectedly higher than symmetric (Ar(2+) Ar(2+)) in contrast with previous observation for covalent molecules or clusters. dissociation (Ar2)(2+)→Ar(+) Ar(+), two well-separated peaks were observed, clearly evidencing that direct Coulombic and radiative charge transfer followed ionic alternatively...
We provide the experimental evidence that single electron capture process in slow collisions between ${\mathrm{O}}^{3+}$ ions and neon dimer targets leads to an unexpected production of low-energy electrons. This results from interatomic Coulombic decay process, subsequent inner-shell one site dimer. Although pure one-electron inner shell is expected be negligible low collision energy regime investigated here, due this overtakes by 1 order magnitude emission Auger electrons scattered...
Magnetic-field uniformity is of the utmost importance in experiments to measure electric dipole moment neutron. A general parametrization magnetic field terms harmonic polynomial modes proposed, going beyond linear-gradients approximation. We review main undesirable effects nonuniformities: depolarization ultracold neutrons and Larmor frequency shifts mercury atoms. The theoretical predictions for these were verified by dedicated measurements with single-chamber neutron...
Electron capture processes for low energy ${\mathrm{Ar}}^{9+}$ ions colliding with ${\mathrm{Ar}}_{2}$ dimer targets are investigated, focusing attention on charge sharing between the two Ar atoms as a function of molecular orientation and impact parameter. A preference charge-asymmetric dissociation channels is observed, strong correlation projectile scattering angle ion orientation. The measurements here provide clear evidence that projectiles distinguish each atom in target electron from...
We present the new spectrometer for neutron electric dipole moment (nEDM) search at Paul Scherrer Institute (PSI), called n2EDM. The setup is room temperature in vacuum using ultracold neutrons. n2EDM features a large UCN double storage chamber design with transport adapted to PSI source. builds on experience gained from previous apparatus operated until 2017. An order of magnitude increase sensitivity calculated baseline based scalable results apparatus, and source performance achieved 2016.
We report the first precise measurement of a $\ensuremath{\beta}$-recoil correlation from radioactive noble gas ($^{6}\mathrm{He}$) confined via magneto-optical trap. The is motivated by search for exotic tensor-type contributions to charged weak current. Interpreted as tensor currents with right-handed neutrinos, measurements yield $|{C}_{T}/{C}_{A}{|}^{2}\ensuremath{\le}0.022$ (90% confidence limit, C.L.). On other hand, left-handed neutrinos limits are $0.007<{C}_{T}/{C}_{A}<0.111$...
Low-energy collision experiments of an argon dimer with Ar9+ were performed to measure branching ratios and kinetic energy release (KER) distributions for multiply ionized dimers. Two well-separated KER peaks are observed at 3.8 5.3 eV the doubly dimers, assigned direct Coulombic dissociation radiative electron capture followed by ionic dissociation, respectively. For channels Ar2++Ar+, Ar3++Ar+ Ar2++Ar2+, show a single peak, positions which agree well those expected dissociation. The ratio...
Single charge transfer in low-energy ${\mathrm{Na}}^{+}+{}^{87}\mathrm{Rb}(5s,5p)$ collisions is investigated using magneto-optically trapped Rb atoms and high-resolution recoil-ion momentum spectroscopy. The three-dimensional reconstruction of the provides accurate relative cross sections for active channels along with their associated distributions projectile scattering angle. measurements are accompanied by molecular close-coupling calculations. predicted diffractionlike oscillations...
We report on the strategy used to optimize sensitivity of our search for a neutron electric dipole moment at Paul Scherrer Institute. Measurements were made upon ultracold neutrons stored within single chamber heart apparatus. A mercury cohabiting magnetometer together with an array cesium magnetometers monitor magnetic field, which was controlled and shaped by series precision field coils. In addition details setup itself, we describe chosen path realize appropriate balance between...
An array of sixteen laser-pumped scalar Cs magnetometers was part the neutron electric dipole moment (nEDM) experiment taking data at Paul Scherrer Institute in 2015 and 2016. It deployed to measure gradients experiment's magnetic field monitor their temporal evolution. The originality lies its compact design, which a single near-infrared diode laser drives all that are located high-vacuum chamber, with selection sensors mounted on high-voltage electrode. We describe details sensors'...
The accurate determination of atomic final states following nuclear $\ensuremath{\beta}$ decay plays an important role in several experiments. In particular, the charge state distributions ions are for determinations $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\nu}$ angular correlation with improved precision. Beyond hydrogenic cases, neutral $^{6}\mathrm{He}$ presents simplest case. Our measurement aims at providing benchmarks to test theoretical calculations. kinematics...
In this article we provide experimental evidence of an interference phenomenon that, to the best our knowledge, has so far not been observed with either matter or light. a nanometer-sized version Feynman's famous two-slit ``thought'' experiment single electrons, managed observe that width quasi-monochromatic line oscillates detection angle. Furthermore, find it occurs in counterphase intensity. We discuss underlying mechanism produces unexpected result.
We present a combined theoretical and experimental study of primary postcollision mechanisms involved when colliding low-energy multiply charged ions with van der Waals dimers. The collision dynamics is investigated using classical calculation based on the Coulombic Over-the-Barrier Model adapted to rare gas dimer targets. Despite its simplicity, model predictions are found in very good agreement results obtained COLd Target Recoil Ion Momentum Spectroscopy, both for relative yields...
The neutron and its hypothetical mirror counterpart, a sterile state degenerate in mass, could spontaneously mix process much faster than the β-decay. Two groups have performed series of experiments search – mirror-neutron ( n − ′) oscillations. They reported no evidence, thereby setting stringent limits on oscillation time τ nn ′ . Later, these data sets been further analyzed by Berezhiani et al.(2009–2017), signals, compatible with oscillations presence magnetic fields, reported. Neutron...
The trapping lasers of a magneto-optical trap have been used to bring Rb atoms into well defined oriented states. Coupled recoil-ion-momentum spectroscopy, this provided unique MOTRIMS setup which was able probe scattering dynamics, including the coherence features, with unprecedented resolution. technique applied low-energy charge exchange reactions ${\mathrm{Na}}^{+}+\mathrm{Rb}(5{p}_{\ifmmode\pm\else\textpm\fi{}1})\ensuremath{\rightarrow}\mathrm{Na}(3p,4s)+{\mathrm{Rb}}^{+}$. measurements...
Precise measurements in the β decay of 35Ar nucleus enable to search for deviations from Standard Model (SM) weak sector. These either check CKM matrix unitarity or constrain existence exotic currents rejected V-A theory SM. For this purpose, β-ν angular correlation parameter, aβν, is inferred a comparison between experimental and simulated recoil ion time-of-flight distributions following quasi-pure Fermi transition 35Ar1+ ions confined transparent Paul trap LPCTrap device at GANIL. During...
Correlations between β decay products are sensitive observables to look for exotic contributions the weak interaction excluded by Standard Model of particle physics. To precisely measure – v angular correlation parameter, αβν, in 6He decay, radioactive atoms trapped a magneto-optical trap and momentum particles 6Li recoil ions measured coincidence. The shake-off process, leading higher charge states Li, plays an important role this observation must be studied carefully. Its study provides...
Abstract Psychological bias towards, or away from, prior measurements theory predictions is an intrinsic threat to any data analysis. While various methods can be used try avoid such a bias, e.g. actively avoiding looking at the result, only blinding traceable and trustworthy method that circumvent convince public audience there not even accidental psychological bias. Data nowadays standard practice in particle physics, but it particularly difficult for experiments searching neutron electric...
We present a method to measure the binary diffusion coefficient of mercury atoms in gas at room temperature and low pressure. It is based on measurement longitudinal spin relaxation optically pumped mercury-199 magnetic field gradient. provide consistent set coefficients for helium-3, helium-4, argon, krypton, xenon, nitrogen, carbon dioxide, oxygen, air.
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