https://doi.org/10.1140/epja/i2008-10668-4
Regular Article - Theoretical Physics
A practical guide to unravel time-like transition form factors
1
Enrico Fermi Center, Rome, Italy
2
INFN, Laboratori Nazionali di Frascati, Frascati, Italy
* e-mail: Simone.Pacetti@lnf.infn.it
Received:
21
July
2008
Revised:
3
October
2008
Accepted:
15
October
2008
Published online:
17
November
2008
A method to determine masses, widths and coupling constants of vector mesons, like 
(1020) , 
(782) and 
(770) recurrences is defined. Starting from data on decay rates and cross-sections for the processes: → M
I
, → M
I
e
+
e
- and e
+
e
- → M
I
, where MI is a pseudoscalar or scalar meson with isospin I = 0, 1 , the time-like transition form factors, which describe the vertex
M
I , are parameterized using a vector-meson-propagators description in the low-energy region ( < 3-4 GeV), the quark-counting rule prescription for the high-energy behavior, and the analyticity imposed by means of the dispersion relations.
PACS: 13.40.Hq Electromagnetic decays – / 11.55.Fv Dispersion relations – / 12.40.Vv Vector-meson dominance – / 11.80.Cr Kinematical properties (helicity and invariant amplitudes, kinematic singularities, etc.) –
© SIF, Springer-Verlag Berlin Heidelberg, 2008
