Related papers: First observation of two hyperfine transitions in …
Context. CF+ has recently been detected in the Horsehead and Orion Bar photo-dissociation regions. The J=1-0 line in the Horsehead is double-peaked in contrast to other millimeter lines. The origin of this double-peak profile may be…
On the basis of quasipotential approach to the bound state problem in QED we calculate the vacuum polarization, relativistic, recoil, structure corrections of orders $\alpha^5$ and $\alpha^6$ to the fine structure interval $\Delta…
We report the first measurement of the \eep three-body breakup reaction cross sections in helium-3 ($^3$He) and tritium ($^3$H) at large momentum transfer ($\langle Q^2 \rangle \approx 1.9$ (GeV/c)$^2$) and $x_B>1$ kinematics, where the…
On the basis of quasipotential method in quantum electrodynamics we calculate corrections of order $\alpha^5$ and $\alpha^6$ to hyperfine structure of S-wave energy levels of muonic deuterium. Relativistic corrections, effects of vacuum…
We perform laser absorption spectroscopy with ultracold $^4$He atoms to measure the energy intervals between the $2^{3\!} P_2$ level and five levels in the n = 5 manifold. The laser light perturbs the cold atomic cloud during the production…
Structural, magnetic and electrical-transport properties of {\alpha}-LiFeO2, crystallizing in the rock salt structure with random distribution of Li and Fe ions, have been studied by synchrotron X-ray diffraction, 57Fe M\"ossbauer…
We report the first measurement of the $(e,e'p)$ reaction cross-section ratios for Helium-3 ($^3$He), Tritium ($^3$H), and Deuterium ($d$). The measurement covered a missing momentum range of $40 \le p_{miss} \le 550$ MeV$/c$, at large…
The quasi-skutterudite superconductor La$_3$Co$_4$Sn$_{13}$ undergoes a phase transition at $T^*=152$ K. By measuring the temperature dependence of heat capacity, electrical resistivity, and the superlattice reflection intensity using…
Numerous few-electron atomic systems are considered which can be used effectively for observing a potential variation of the fine-structure constant $\alpha$ and the electron-proton mass ratio $m_e/m_p$. We examine optical magnetic dipole…
We report new experimental hyperfine structure (HFS) constants of neutral and singly ionized scandium (Sc I and Sc II). We observed spectra of Sc-Ar and Sc-Ne hollow cathode discharges in the region 200-2500 nm (50,000-4000 cm$^{-1}$) using…
While measurements of the hyperfine structure of hydrogen-like atoms are traditionally regarded as test of bound-state QED, we assume that theoretical QED predictions are accurate and discuss the information about the electromagnetic…
Corrections of orders alpha^5 and alpha^6 are calculated in the hyperfine splittings of 1S and 2S - energy levels in the ion of muonic helium. The electron vacuum polarization effects, the nuclear structure corrections and recoil…
Hyperfine structure of the ground $2^{2}S-$states of the three-electron atoms and ions is investigated. By using our recent numerical values for the doublet electron density at the atomic nucleus we determine the hyperfine structure of the…
The ground state hyperfine splitting of positronium, $\Delta_{\mathrm{HFS}}$, is sensitive to high order corrections of QED. A new calculation up to $\mathrm{O}(\alpha ^3 \ln \alpha)$ has revealed a $3.9\sigma$ discrepancy between the QED…
Laser spectroscopy of the low lying $^1$P and $^3$D states in atomic barium has been performed. This work contributes substantially to the development of an effective laser cooling and trapping for heavy alkaline earth elements and aims in…
Post-selecting output states in measurements can effectively amplify weak signals and improve precision. However, post-selection effects may also introduce unintended biases in precision measurements. Here, we investigate the influence of…
The pressure evolution of the local structure of Fe2O3 hematite has been determined for the first time by extended x-ray absorption fine structure up to 79 GPa. The comparison to the different high-pressure forms proposed in the literature…
We report a microwave spectroscopy measurement of the muonium $2S_{1/2}-2P_{3/2}$ fine structure transition, yielding a transition frequency of $9871.0 \pm 7.0~\mathrm{MHz}$, in agreement with state-of-the-art QED predictions within one…
Measuring the hyperfine structure (HFS) of long-lived $^3P_2$ states of divalent atoms may offer the opportunity of extracting relatively unexplored nuclear magnetic octupole and electric hexadecapole moments. Here, using relativistic…
The hyperfine structure of atoms and ions is widely used in fundamental and applied research. Accurate knowledge of hyperfine splitting values is essential for quantum metrology applications as well as for improving the performance of…