6533b854fe1ef96bd12addf3
RESEARCH PRODUCT
Neutral pion production at threshold and low-energy theorems
R. DahmStefan Scherersubject
QuarkChiral anomalyPhysicsNuclear and High Energy PhysicsExplicit symmetry breakingParticle physicsPionIsospinSpontaneous symmetry breakingQuantum electrodynamicsNuclear TheorySymmetry breakingChiral symmetry breakingdescription
Abstract Recent experiments of neutral pion photoproduction show a strong discrepancy between experimental data and the predictions of low-energy theorems (LET). The basic ingredients of these theorems are the conservation of the electromagnetic current and the hypothesis of a partially conserved axial current (PCAC). Both, anomalies in the t-channel, and rescattering in a simple R-matrix formalism, lead to small corrections of the order of 10 – 20 %. However, the investigation of the effects of chiral symmetry breaking and isospin symmetry breaking at the quark level in a current algebraic approach leads to substantial contributions of the right order of magnitude.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1990-01-01 | Progress in Particle and Nuclear Physics |