Related papers: Internal structure and positron annihilation in th…
Properties of some few-body systems which include one positively charged muon $\mu^{+}$ and two electrons $e^{-}$ are discussed. In particular, we consider the negatively charged muonium ion Mu$^{-}$ (or $\mu^{+} e^{-}_{2}$) and four-body…
The life-time of the four-body atomic system MuPs ($\mu^{+} e^{-}_2 e^{+}$ or muonium-positronium) against positron annihilation has been evaluated as $\tau = \frac{1}{\Gamma} \approx 4.076453 \cdot 10^{-10}$ $sec$. Various annihilation…
The hyperfine structure of the ground states in a number of positronium hydrides (TPs, DPs, ${}^{1}$HPs) and MuPs ($\mu^{+} e^{-}_2 e^{+}$) is determined with the use of highly accurate variational wave functions. We also evaluate the…
Bound state properties of the ground (bound) ${}^{1}S(L = 0)-$state(s) in the four-body positronium hydrides ${}^{1}$HPs, ${}^{2}$HPs (DPs), ${}^{3}$HPs (TPs) and MuPs are determined and investigated. By using numerical data from our…
Based on the results of accurate variational calculations we demonstrate stability of the five-body negatively charged ions $a^{+} b^{+} \mu^{-} e^{-} e^{-}$. Each of these five-body ions contains two electrons $e^{-}$, one negatively…
On the basis of quasipotential approach to the bound state problem in quantum electrodynamics we calculate hyperfine structure intervals Delta E^{hfs}(2P_{1/2}) and Delta E^{hfs}(2P_{3/2}) for P-states in muonic deuterium. The tensor method…
We consider the hyperfine structure, the atomic spectrum and the decay channels of the bound mu+ mu- system (dimuonium). The annihilation lifetimes of low-lying atomic states of the system lie in the nanosecond range range. The decay rates…
The hyperfine structure splittings are determined for all five bound $S(L = 0)-$states in the three symmetric muonic molecular ions: $pp\mu, dd\mu$ and $tt\mu$. The expectation values of all interparticle delta-functions used in our…
The hyperfine structure of the interstitial muonium (Mu) center in rutile (TiO$_2$, weakly $n$-type) has been identified by means of muon spin rotation technique. The angle-resolved hyperfine parameter has a tetragonal anisotropy within 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…
Total energies and various bound state properties are determined for the ground states in all six four-body muonic $a^{+} b^{+} \mu^{-} e^{-}$ quasi-atoms. These quasi-atoms contain two nuclei of the hydrogen isotopes $p^{+}, d^{+}, t^{+}$,…
The local electronic structure of muons (Mu) as dilute pseudo-hydrogen in single-crystalline $\beta$-Ga$_2$O$_3$ has been studied by the muon spin rotation/relaxation ($\mu$SR). High-precision measurements over a long time range of $\sim$25…
The hyperfine structure splittings of the ground states of the $pd\mu, pt\mu$ and $dt\mu$ ions are determined with the use of highly accurate expectation values of the interparticle delta-functions obtained in recent computations. The…
The energy levels of the muonium ($\mu^+ e^-$) atom, which consists of two ''point-like'' leptonic particles, can be calculated to very high accuracy in the framework of bound state Quantum Electrodynamics (QED), since there are no…
On the basis of perturbation theory in fine structure constant alpha and the ratio of electron to muon masses we calculate one-loop vacuum polarization, electron vertex corrections, nuclear structure and recoil corrections to hyperfine…
The structure of the unnatural parity states of PsH, LiPs, NaPs and KPs are investigated with the configuration interaction and stochastic variational methods. The binding energies (in hartree) are found to be 8.17x10-4, 4.42x10-4,…
Stability of the bound ground states in the six five-body muonic $a b \mu e_2$ ions (or $(a b \mu e_2)^{-}$) and ten six-body $a b c \mu e_2$ quasi-molecules is investigated. The notations $a, b, c$ stand for the bare nuclei of three…
We calculate hyperfine structure intervals $\Delta E^{hfs}(2P_{1/2})$ and $\Delta E^{hfs}(2P_{3/2})$ for P-states in muonic ions of lithium, beryllium and boron. To construct the particle interaction operator in momentum space we use the…
The search for axion-like particles $X$ in muon decays is an excellent opportunity for the MEG II and Mu3e experiments to extend their horizons beyond $\mu^+ \to e^+ \gamma$ and $\mu^+ \to e^+ e^- e^+$. A suitable process for both…
Results are obtained for the decay rate of ortho and para states and for the hyperfine structure of the dimuonic system mu+ mu- (dimuonium). We calculate next--to-leading order radiative corrections. It is shown that previously reported…