Two-pion induced self-energy contributions to the ρ-meson mass are examined in relation to the quenched approximation of QCD, where the physics associated with two-pion intermediate states has been excluded from vectorisovector correlation functions. Corrections to quenched QCD calculations of the ρ-meson mass are estimated to be small at the order of a few percent of the ρ-meson mass. The two-...

Off-shell aspects of the one-pion-exchange potential and their relationship to different forms of the nonstatic (subleading-order) chiral two-pion-exchange nucleon-nucleon potential are discussed. Various types of off-shell behavior are categorized and numerous examples are given. Recently derived potentials based on chiral approaches are supplemented by a rather general form of the two-pion-ex...

Objective: The electric (ᾱ) and magnetic (β̄) pion Compton polarizabilities characterize the pion’s deformation in the electromagnetic field of the γ during γπ Compton scattering. They depend on the rigidity of the pion’s internal structure as a composite particle. The polarizabilities deduced by Antipov et al. in their low statistics Primakoff experiment (∼ 7000 events) were ᾱπ = −β̄π = 6.8 ± 1....

We have investigated the neutrino induced coherent pion production reaction at low and intermediate energies including pion, nucleon and ∆(1232) resonance. Medium effects in the production mechanism and the distortion of the pion wave function are included in the calculation. We find a strong reduction of the cross section due to these effects and also substantial modifications in the energy di...

A general derivation of the multi-pion correlation function for completely chaotic source is given. Its effects on the pion multiplicity distribution, twopion interferometry are studied. A generalized multi-pion correlation function for a partially coherent source is also discussed.