The Kπ form factors from Analyticity and Unitarity
Abstract
Analyticity and unitarity techniques are employed to obtain bounds on the shape parameters of the scalar and vector form factors of semileptonic K_{l3} decays. For this purpose we use vector and scalar correlators evaluated in pQCD, a low energy theorem for scalar form factor, lattice results for the ratio of kaon and pion decay constants, chiral perturbation theory calculations for the scalar form factor at the CallanTreiman point and experimental information on the phase and modulus of Kπ form factors up to an energy t_{in} = 1GeV^{2}. We further derive regions on the real axis and in the complexenergy plane where the form factors cannot have zeros.
 Publication:

Journal of Physics Conference Series
 Pub Date:
 July 2012
 DOI:
 10.1088/17426596/374/1/012012
 arXiv:
 arXiv:1202.5399
 Bibcode:
 2012JPhCS.374a2012A
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 6 pages, 5 figures