相关论文: On Quasipositronia

The existence of dark matter provides strong evidence for physics beyond the Standard Model. Extending the Standard Model with the Peccei-Quinn symmetry and/or supersymmetry, compelling dark matter candidates appear. For the axion, the…

Supported by results obtained with semi-classical quantization techniques, and with a quantum mechanical "square-root Klein-Gordon" operator, it is argued that Positronium (Ps) may exhibit a proper quantum-mechanical ground state whose…

Since the time of Rutherford 1911) physicists and chemists commonly believed that with no electric field, the nucleus of an atom is at the centre of the electron cloud, atoms do not have permanent electric dipole moment (EDM), so that there…

Scintillation properties of pure CsI crystals used in the shower calorimeter being built for precise determination of the pi+ -> pi0 e+ nu decay rate are reported. Seventy-four individual crystals, polished and wrapped in Teflon foil, were…

The most general form of the hamiltonian for the muon decay is presented. We assume that it arises as a result of the exchange of intermediate bosons with a momentum $q$ and naturally should depend on this momentum. That allows us to…

The potential of decays of mesons containing heavy quarks [including $B$ mesons and the $\Upsilon(1S)$] for producing final states of matter with unusual quark configurations, such as $q q \bar q \bar q$ or $q q q q \bar q$, is…

We consider nonholonomic systems which symmetry groups consist of two subgroups one of which represents rotations about the axis of symmetry. After nonholonomic reduction by another subgroup the corresponding vector fields on partially…

The theory of QED corrections to hyperfine structure in light hydrogenic atoms and ions has recently advanced to the point that the uncertainty of these corrections is much smaller than 1 part per million (ppm), while the experiments are…

Positronium is the short-lived atom consisting of a bound electron-positron pair. In the triplet state, when the spins of both particles are parallel, radiative recombination lines will be emitted prior to annihilation. The existence of…

We show that the form factor of an electron or a muon is unity for the modulus of the momentum transfer away from the Hagedorn temperatures $T^{e}_0\sim m_e$ and $T^{\mu}_0\sim m_\mu$ and lower than the hadronic Hagedorn temperature…

In the attempt of including leptons in the scheme of a matter-antimatter asymmetry originated from CP violation in the primordial Universe, it is proposed of re-christening e-, muon-, tau- and their associated neutrinos as 'antiparticles'…

In the framework of the quasipotential method in quantum electrodynamics we calculate the contribution of pseudoscalar mesons to the interaction operator of a muon and a proton in muonic hydrogen atom. The parametrization of the transition…

This article reviews recent theoretical developments in the ab initio study of polarons in materials. The polaron is an emergent quasiparticle that arises from the interaction between electrons and phonons in solids, and consists of an…

A selection of results from electron-positron collisions at BESIII are reviewed. The results presented here illustrate the wide range of physics topics that can be studied using the Beijing Electron Positron Collider~(BEPC). At low…

Supernovae provide fascinating opportunities to study various particles and their interactions. Among these there are neutrinos, axions, and other light weakly interacting particles, which play a significant role in our understanding of…

The ground bound states in the five-body muonic ions $a b \mu e_2$ (or $(a b \mu e_2)^{-}$), where $(a, b) = (p, d, t)$, are considered for the first time. As follows from accurate numerical computations of these five-body ions they are…

We design two-dimensional (2D) mechanical metamaterials that may be deformed substantially at little or no energy cost. Examples of such deformable structures are assemblies of rigid isosceles triangles hinged in their corners on the…

We interpret experimentally known B-Mg-Ru crystals as quasicrystal approximants. These approximant structures imply a deterministic decoration of tiles by atoms that can be extended quasiperiodically. Experimentally observed structural…

Classifying interactions is key in the physical sciences, and bonding mechanisms in matter-antimatter systems remain particularly enigmatic. Here we focus on a paradigmatic example of positronium hydride (PsH) dimer composed of two protons,…

We explore the possibility of performing nuclear structure studies using low energy neutrino beams. In particular, low energy beta-beams and conventional sources (muon decay-at-rest) are considered. We present results on the total…