https://doi.org/10.1140/epjc/s10052-015-3778-x
Regular Article - Theoretical Physics
Two-hadron saturation for the pseudoscalar–vector–vector correlator and phenomenological applications
1
Faculty of Mathematics and Physics, Institute of Particle and Nuclear Physics, Charles University, V Holešovičkách 2, Prague 8, Czech Republic
2
Institutionen för Fysik och Astronomi, Uppsala Universitet, Box 516, 75120, Uppsala, Sweden
* e-mail: husek@ipnp.mff.cuni.cz
Received:
1
September
2015
Accepted:
5
November
2015
Published online:
12
December
2015
The pseudoscalar–vector–vector correlator is constructed using two meson multiplets in the vector and two in the pseudoscalar channel. The parameters are constrained by the operator product expansion at leading order where two or all three momenta are considered as large. Demanding in addition the Brodsky–Lepage limit one obtains (in the chiral limit) a pion-vector-vector (
VV) correlator with only one free parameter. The singly virtual pion transition form factor 
and the decay width of 
are independent of this parameter and can serve as cross-checks of the results. The free parameter is determined from a fit of the 
– transition form factor 
. The resulting VV correlator is used to calculate the decay widths 
and 
and finally the widths of the rare decay 
and of the Dalitz decay 
. Incorporating radiative QED corrections the calculations of 
decays are compared to the KTeV results. We find a deviation of 2 
or less for the rare pion decay.
© The Author(s), 2015
