Regular Article - Theoretical Physics
Constraining the low-energy pion electromagnetic form factor with spacelike data
Centre for High Energy Physics, Indian Institute of Science, Bangalore, 560 012, India
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Published online: 1 February 2008
The pionic contribution to the g-2 of the muon involves a certain integral over the modulus squared of Fπ(t), the electromagnetic form factor of the pion. We extend techniques that use cut-plane analyticity properties of Fπ(t) in order to account for present day estimates of the pionic contribution and experimental information at a finite number of points in the spacelike region. Using data from several experiments over a large kinematic range for |t|, we find bounds on the expansion coefficients of Fπ(t), sub-leading to the charge radius. The value of one of these coefficients in chiral perturbation theory respects these bounds. Furthermore, we present a sensitivity analysis to the inputs. A brief comparison with results in the literature that use observables other than the g-2 and timelike data is presented.
© Springer-Verlag , 2008