Constraints on the omega pi form factor from analyticity and unitarity

Ananthanarayan, B and Caprini, I and Kubis, B (2014) Constraints on the omega pi form factor from analyticity and unitarity. In: EUROPEAN PHYSICAL JOURNAL C, 74 (12).

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Abstract

Motivated by the discrepancies noted recently between the theoretical calculations of the electromagnetic omega pi form factor and certain experimental data, we investigate this form factor using analyticity and unitarity in a framework known as the method of unitarity bounds. We use a QCD correlator computed on the spacelike axis by operator product expansion and perturbative QCD as input, and exploit unitarity and the positivity of its spectral function, including the two-pion contribution that can be reliably calculated using high-precision data on the pion form factor. From this information, we derive upper and lower bounds on the modulus of the omega pi form factor in the elastic region. The results provide a significant check on those obtained with standard dispersion relations, confirming the existence of a disagreement with experimental data in the region around 0.6 GeV.

Item Type:	Journal Article
Publication:	EUROPEAN PHYSICAL JOURNAL C
Publisher:	SPRINGER
Additional Information:	Copy right for this article belongs to the SPRINGER, 233 SPRING ST, NEW YORK, NY 10013 USA
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited:	06 Feb 2015 14:50
Last Modified:	06 Feb 2015 14:50
URI:	http://eprints.iisc.ac.in/id/eprint/50779

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