arXiv subjects

V. Matousek

Publications and source records attributed to V. Matousek.

4 recordsLinked to original sources

arXiv2026

Charge radii of Cl isotopes from x-ray spectroscopy of muonic atoms

Nuclear charge radii are vital for nuclear and atomic physics, the determination of fundamental constants, and searches for new physics. Muonic atoms, where a single negative muon orbits a nucleus, are sensitive tools for determining nuclear radii due to the large wavefunction overlap of the muon and nucleus. Here we report on a new measurement of the $2, 3, 4p\to1s$ x-ray energies in muonic $^{35,37}$Cl with uncertainties reaching 18 ppm. By employing a large-scale germanium detector array, it was possible to extract these energies from a high statistics dataset using highly enriched samples of only a few tens of milligrams. Combining these results with state-of-the-art atomic and nuclear theory input, the charge radii of the stable chlorine isotopes were determined to be $R(^{35}\text{Cl}) = 3.3333(23)~fm$ and $R(^{37}\text{Cl}) = 3.3444(23)~fm$. This is an order of magnitude more precise and significantly different from previously tabulated values. Our new values solve a discrepancy observed for the charge radius difference in mirror nuclei, agreeing with the overall global trend. The charge radius difference $\delta \langle r^2 \rangle (^{37}\text{Cl} - {^{35}\text{Cl}}) = -0.0776(64)~fm^2$ we extract is 25 times more precise than the previous values. This precision is crucial for establishing reference values for future laser spectroscopy measurements of radioactive isotopes.

nucl-ex↗

arXiv2025

Modern approach to muonic x-ray spectroscopy demonstrated through the measurement of stable Cl radii

Recent advances in muonic x-ray experiments have reinvigorated efforts in measurements of absolute nuclear charge radii. Here, a modern approach is presented, and demonstrated through determination of the charge radii of the two stable chlorine nuclides $^{35}$Cl and $^{37}$Cl. Knowledge of these radii has implications for fundamental studies in nuclear and atomic physics. For this purpose, a state-of-the-art experiment was performed at the $\pi$E1 beamline in the Paul Scherrer Institute (Switzerland), using a large-scale HPGe detector array in order to extract precise energies of the muonic $^{35}$Cl and $^{37}$Cl $np1s$ transitions. The nuclear charge radius extraction relies on modern calculations for QED effects and nuclear polarization with rigorous uncertainty quantification, including effects that were not accounted for in older studies. Additionally, we established a new method for applying the nuclear shape correction directly from energy density functionals, which are amenable to isotopes for which no high-quality electron scattering experiments are available. The resulting charge radii are $3.3335(23) fm$ for $^{35}$Cl and $3.3445(23) fm$ for $^{37}$Cl, thus improving the uncertainty of the available electron scattering values by a factor of seven. The correlation of several observables was evaluated between the different isotopes in order to produce a more precise value of the differential mean square charge radius $\delta \langle r^2 \rangle^{37, 35}=+0.0771(66) fm^{2}$. In this case, improvement of the uncertainty by more than one order of magnitude was achieved compared to the literature value. This precision is sufficient to use this differential as input for isotope shift factor determination.

nucl-ex↗

arXiv2016

A new technique for elucidating $\beta$-decay schemes which involve daughter nuclei with very low energy excited states

A new technique of elucidating $\beta$-decay schemes of isotopes with large density of states at low excitation energies has been developed, in which a Broad Energy Germanium (BEGe) detector is used in conjunction with coaxial hyper-pure germanium detectors. The power of this technique has been demonstrated on the example of 183Hg decay. Mass-separated samples of 183Hg were produced by a deposition of the low-energy radioactive-ion beam delivered by the ISOLDE facility at CERN. The excellent energy resolution of the BEGe detector allowed $\gamma$ rays energies to be determined with a precision of a few tens of electronvolts, which was sufficient for the analysis of the Rydberg-Ritz combinations in the level scheme. The timestamped structure of the data was used for unambiguous separation of $\gamma$ rays arising from the decay of 183Hg from those due to the daughter decays.

physics.ins-det↗

arXiv2010

The 270 MeV deuteron beam polarimeter at the Nuclotron Internal Target Station

A deuteron beam polarimeter has been constructed at the Internal Target Station at the Nuclotron of JINR. The polarimeter is based on spin-asymmetry measurements in the d-p elastic scattering at large angles and the deuteron kinetic energy of 270 MeV. It allows to measure vector and tensor components of the deuteron beam polarization simultaneously.

nucl-ex↗