Anomalous decays of eta %26apos; and eta into four pions

作者：Guo Feng Kun^*; Kubis Bastian; Wirzba Andreas

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2012, 85(1): 014014.

DOI：10.1103/PhysRevD.85.014014

We calculate the branching ratios of the yet unmeasured eta decays into four pions, based on a combination of chiral perturbation theory and vector-meson dominance. The decays eta %26apos;-%26gt; 2 (pi(+) pi(-))and eta %26apos; -%26gt; pi(+) pi(-) 2 pi(0) are P-wave dominated and can largely be thought to proceed via two rho resonances; we predict branching fractions of (1.0 +/- 0.3) x 10(-4) and (2.4 +/- 0.7) x 10(-4) respectively, not much lower than the current experimental upper limits. The decays eta %26apos; -%26gt; 4 pi(0) and eta -%26gt; 4 pi(0) in contrast, are D-wave driven as long as conservation of CP symmetry is assumed, and are significantly further suppressed; any experimental evidence for the decay eta -%26gt; 4 pi(0) could almost certainly be interpreted as a signal of CP violation. We also calculate the CP-violating amplitudes for eta %26apos; -%26gt; 4 pi(0) and eta -%26gt; 4 pi(0) induced by the QCD theta-term.

• 出版日期2012-1-12