6533b85dfe1ef96bd12bdd94
RESEARCH PRODUCT
Chiral nonperturvative approach to the isoscalar s-wave pion-pion interaction in a nuclear medium
M. J. Vicente VacasH.c. ChiangE. Osetsubject
PhysicsNuclear and High Energy PhysicsParticle physicsNuclear TheoryScatteringIsoscalarHigh Energy Physics::LatticeScalar (mathematics)Nuclear TheoryFísicaFOS: Physical sciencesIntegral equationRenormalizationNuclear Theory (nucl-th)Algebraic equationPionAmplitudeHigh Energy Physics::ExperimentNuclear Experimentdescription
The s-wave isoscalar amplitude for pion-pion scattering in a nuclear medium is evaluated using a nonperturbative unitary coupled channels method and the standard chiral Lagrangians. The method has proved successful to describe the pion-pion properties in the scalar isoscalar channel up to 1.2 GeV giving rise to poles in the t matrix for the f0(980) and the sigma. The extension of the method to the nuclear medium implies not only the renormalization of the pions in the medium, but also the introduction of interaction terms related to contact terms in the pion-nucleon to pion-pion-nucleon interaction. Off shell effects are also shown to be important leading to cancellations which reduce the coupled channel integral equations to a set of algebraic equations. As the density increases we find a reduction of strength below the $\sigma$ region and a certain accumulation of strength at energies around pion threshold. Our results, based on chiral Lagrangians, provide similar results to those obtained with phenomenological models which impose minimal chiral constraints.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1997-12-12 |