We review the theory of hadronic atoms in QCD+ QED, based on a non-relativistic effective
Lagrangian framework. We first provide an introduction to the theory, and then describe …

We investigate the ground-state energy of the π^-p atom (pionic hydrogen) in the framework
of QCD+ QED. In particular, we evaluate the strong energy-level shift. We perform the …

The low energy scattering of pions is investigated in the presence of electromagnetic
interactions at leading order and at next-to-leading order for the amplitudes involving at most …

We construct an effective non-relativistic quantum field theory that describes bound states of
π+ π− pairs and their hadronic decays. We then derive a general expression for the lifetime …

The general formula of the π− p atom strong energy-level shift in the 1s state is derived in
the next-to-leading order in the isospin breaking, and in all orders in chiral expansion …

The pionium decay width, the measurement of which allows determination of the scattering
amplitude of the process π+ π−→ π 0 π 0 near threshold, is evaluated in the framework of …

We review the theory of hadronic atoms in the framework of quantum chromodynamics, with
photons and electrons included (QCD+ QED). We illustrate the method by means of π+ π …

The hadronic π+ π− atom is studied in the relativistic perturbative approach based on the
Bethe-Salpeter equation. The general expression for the atom lifetime is derived. Lowest …

The π+ π− atom decays–in the ground state–predominantly into two neutral pions. We
present a general expression for the corresponding decay width in the framework of QCD …

We apply Chiral perturbation theory at one loop to analyze the general formula for the π+ π−
atom lifetime derived recently in the framework of QCD [A. Gall et al., Phys. Lett. B 462 …