S-wave π-nucleus repulsion and Dirac phenomenology

Density dependence of the s-wave repulsion in pionic atoms

Several mechanisms of density dependence of the s-wave repulsion in pionic atoms, beyond the conventional model, are tested by parameter fits to a large (106 points) set of data from 16O to 238U, including ‘deeply bound’ states in 205Pb. Special attention is paid to the proper choice of nuclear density distributions. A density-dependent isovector scattering amplitude suggested recently by Weise...

Measure of π ’ s and Λ ’ s emitter radius via Bose - Einstein and Fermi - Dirac Statistics

This report summarises the recent studies of the Bose-Einstein Correlations (BEC) carried out by the four LEP experiments using hadronic Z 0 decay events and e + e − reactions leading to the WW decay final states. The three identical charged pion systems π ± π ± π ± have been studied by OPAL with 4 × 10 6 hadronic Z 0 decays events. The genuine three-pion correlations corrected for Coulomb effe...

Metastable π junction between an s(±)-wave and an s-wave superconductor.

We examine a contact between a superconductor whose order parameter changes sign across the Brillioun zone, and an ordinary, uniform-sign superconductor. Within a Ginzburg-Landau-type model, we find that if the barrier between the two superconductors is not too high, the frustration of the Josephson coupling between different portions of the Fermi surface across the contact can lead to surprisi...

A joint analysis of the S – wave in the π + π − and π 0 π 0 data

Separation of S – wave pseudoscalar and pseudovector amplitudes in π − p ↑ → π + π − n reaction on polarized target