Related papers: Structure of double pionic atoms
A review of the modern theory of hadronic atoms based on the non-relativistic effective Lagrangian approach and ChPT, is given. As an application of the general framework, we consider the decay of the pi+pi- atom into two neutral pions, and…
We explore the bound electron pairs (BEPs) arising due to the pair spin-orbit interaction (PSOI) in two-dimensional structures with a gate that can allow the BEPs to be manipulated. The gate breaks the in-plane reflection symmetry of the…
The pion-production $\pi^+ A \to \pi^+\pi^{\pm} A'$ reactions were studied on nuclei $^{2}H$, $^{12}C$, $^{40}Ca$ and $^{208}Pb$ at a pion energy of $T_{\pi^{+}}$=283 MeV using the CHAOS spectrometer. The experimental results are reduced to…
We investigate isospin breaking in low-energy pion-nucleon scattering in the framework of chiral perturbation theory. This work extends the systematic analysis of [1] to the energy range above threshold. Various relations, which identically…
The pion structure function is investigated in a simple model, where pion and constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi-> gamma* pi scattering amplitude is…
The influence of strong $\pi^+\pi^-$ interaction of the behaviour of pionium nS-state wave functions at small distance are investigated both analytically (perturbatively) and so numerically. It is shown that in the whole the accounting of…
We have developed a model for the N N --> N N pi pi reaction and evaluated cross sections for the different charged channels. The low energy part of those channels where the pions can be in an isospin zero state is dominated by N*…
The $\pi^-/\pi^+$ ratio is examined as a function of isospin asymmetry and beam energy for central collisions induced by neutron-rich nuclei within an isospin-dependent hadronic transport model. The $\pi^-/\pi^+$ ratio is found to increase…
We investigate here ground state properties of atoms, in which substitute fermions -- electrons by bosons, e.g. $\pi $ - meson. We perform some calculations in the frame of modified Hartree-Fock (HF) equation. The modification takes into…
We present the calculation of the binding energy of 2p pion for various central charges Z. We have taken into account the interaction between the magnetic moment of the nucleus and the orbital magnetic moment of the pion. The obtained…
In the scattering of positive pions by nuclei the double-charge-exchange (DCX) reaction creates the possibility of formation of pionic atom states in the vicinity of the threshold of this reaction. These quasi stationary states can manifest…
We consider double-photon and bremsstrahlung mechanisms for the production of two charged pions in high-energy electron (or proton) scattering off a transversely polarised proton. Interference between the relevant amplitudes generates a…
We calculate the pion self-energies in asymmetric nuclear matter in the two-loop approximation of chiral perturbation theory. We find three types of corrections beyond the well-known linear density approximation. The resulting s-wave…
The binding energies of the deeply bound 1s and 2p states in pionic atoms of $^{207}$Pb, recently established experimentally in the $^{208}$Pb(d,$^3$He) reaction, have been used by several groups to derive the pion effective mass in nuclear…
This presentation reviews recent developments in the understanding of low-energy pion- and kaon-nucleon interactions as they relate to deeply bound pionic atoms and possible antikaon-nuclear bound states. A brief update is given on 1s…
The doubly differential cross sections for the $^4$He$(\pi^+,\pi^-) 4p$ reaction were calculated using both a two-nucleon sequential single charge exchange model and an intranuclear cascade code. Final state interactions between the two…
We study electromagnetic as well as strong isospin breaking effects in the isospin mass splittings of light pseudoscalar and vector mesons. To this end we employ a coupled system of quark Dyson-Schwinger and meson Bethe-Salpeter equations…
The phase structure of a two-fluid bosonic system is investigated. The proton-neutron interacting boson model (IBM-2) posesses a rich phase structure involving three control parameters and multiple order parameters. The surfaces of quantum…
A systematic study of the $\pi^-/\pi^+$ ratio in heavy-ion collisions with the same neutron/proton ratio but different masses can help single out effects of the nuclear mean field on pion production. Based on simulations using the IBUU04…
We consider pion-nucleon scattering in heavy-baryon chiral perturbation theory to third order. All electromagnetic corrections appearing to this order are included. We thus have a consistent description of strong and electromagnetic…