Constraining the low-energy pion electromagnetic form factor with space-like and phase of time-like data

Ananthanarayan, B and Ramanan, S (2009) Constraining the low-energy pion electromagnetic form factor with space-like and phase of time-like data. In: The European Physical Journal C - Particles and Fields, 60 (1). pp. 73-81.

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Abstract

The Taylor coefficients c and d of the EM form factor of the pion are constrained using analyticity, knowledge of the phase of the form factor in the time-like region, 4m(pi)(2) <= t <= t(in) and its value at one space-like point, using as input the (g - 2) of the muon. This is achieved using the technique of Lagrange multipliers, which gives a transparent expression for the corresponding bounds. We present a detailed study of the sensitivity of the bounds to the choice of time-like phase and errors present in the space-like data, taken from recent experiments. We find that our results constrain c stringently. We compare our results with those in the literature and find agreement with the chiral perturbation-theory results for c. We obtain d similar to O(10) GeV-6 when c is set to the chiral perturbation-theory values.

Item Type:	Journal Article
Publication:	The European Physical Journal C - Particles and Fields
Publisher:	Spriger
Additional Information:	Copyright of this article belongs to Springer.
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited:	30 Apr 2009 04:23
Last Modified:	19 Sep 2010 05:29
URI:	http://eprints.iisc.ac.in/id/eprint/19570

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