Axial anomaly and the interplay of quark loops with pseudoscalar and vector mesons in the γ∗→π+π0π− process

Scientific paper - Original scientific paper

• Author: Sanjin Benić
• Author: Dubravko Klabučar
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

Motivated by the ongoing measurements of the Primakoff process π−γ∗→π−π0 by the COMPASS Collaboration at CERN, the transition form factor for the canonical anomalous process γ∗→π+π0π− 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 ρ and the ω, 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.

• Keywords (english): constituent quark; axial anomaly; transition form factor; pion; pseudoscalar meson; vector meson
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical Review D - Particles, Fields, Gravitation and Cosmology
• Numbering: vol. 85, no. 3, 034042
• p-ISSN: 1550-7998
• e-ISSN: 1550-2368
• DOI: https://doi.org/10.1103/PhysRevD.85.034042
• URN:NBN: urn:nbn:hr:217:586170
• Publication: 2012
• Project: Number: 119-0982930-1016; Title (croatian): Elementarne čestice, teorija polja i kozmologija; Leader: Ivica Picek; Jurisdiction: Croatia; Funding stream: ZP
• Document URL: http://link.aps.org/doi/10.1103/PhysRevD.85.034042
• Type of resource: Text
• Access conditions: Open access
• Public note: Copyright (2012) by the American Physical Society. Received 15 September 2011; revised manuscript received 16 January 2012; published 28 February 2012.
• Created on: 2019-11-16 10:06:56