Naslov
Axial anomaly and the interplay of quark loops with pseudoscalar and vector mesons in the gamma* --> pi+ pi0 pi- process

Autori
Benić, Sanjin ; Klabučar, Dubravko

Izvornik
Physical Review D - Particles, Fields, Gravitation, and Cosmology (1550-7998) 85 (2012), 3; 034042-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
constituent quark; axial anomaly; transition form factor; pion; pseudoscalar meson; vector meson

Sažetak
Motivated by the ongoing measurements of the Primakoff process pi^- gamma^* --> pi^- pi^0 by COMPASS collaboration at CERN, the transition form factor for the canonical anomalous process gamma^* --> pi^+ pi^0 pi^- is calculated in a constituent quark loop model. The simplest contribution to this process is the quark "box" amplitude. In the present paper we also explicitly include the vector meson degrees of freedom, i.e., the rho and the omega, thus giving rise to additional, resonant contributions. We find that in order to satisfy the axial anomaly result, a further subtraction in the resonant part is needed. The results are then compared with the vector meson dominance model as well as the Dyson--Schwinger calculations, the chiral perturbation theory result, and the available data.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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