https://doi.org/10.1140/epja/i2009-10801-y
Letter
Improved bounds on the radius and curvature of the K
scalar form factor and implications to low-energy theorems
Centre for High Energy Physics, Indian Institute of Science, 560 012, Bangalore, India
* e-mail: anant@cts.iisc.ernet.in
Received:
11
March
2009
Revised:
26
April
2009
Accepted:
6
May
2009
Published online:
24
May
2009
We obtain stringent bounds in the 〈r
2
-c plane where these are the scalar radius and the curvature parameters of the scalar K
form factor, respectively, using analyticity and dispersion relation constraints, the knowledge of the form factor from the well-known Callan-Treiman point
, as well as at
, which we call the second Callan-Treiman point. The central values of these parameters from a recent determination are accomodated in the allowed region provided the higher loop corrections to the value of the form factor at the second Callan-Treiman point reduce the one-loop result by about 3% with
. Such a variation in magnitude at the second Callan-Treiman point yields 0.12 fm2
〈r
2
0.21 fm2and 0.56 GeV-4
c
1.47 GeV-4and a strong correlation between them. A smaller value of
shifts both bounds to lower values.
PACS: 11.55.Fv Dispersion relations – / 12.39.Fe Chiral Lagrangians –
© SIF, Springer-Verlag Berlin Heidelberg, 2009