Two-hadron saturation for the pseudoscalar-vector€-vector correlator and phenomenological applications

• The pseudoscalar-vector-vector correlator is constructed using two mesonmultiplets 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 (pi VV) correlator with only one free parameter. The singly virtual pion transition form factor F-pi 0 gamma gamma* and the decay width of omega -> pi(0)gamma. are independent of this parameter and can serve as cross-checks of the results. The free parameter is determined from a fit of the omega-pi transition form factor F-pi 0 omega gamma*. The resulting pi VV correlator is used to calculate the decay widths omega -> pi(0) e(+) e(-) and omega -> pi(0) mu(+) mu(-) and finally the widths of the rare decay pi(0) -> e(+) e(-) and of the Dalitz decay pi(0) -> e(+) e(-) gamma(.) Incorporating radiative QED corrections the calculations of pi(0) decays are compared to the KTeV results. We find a deviation of 2 sigma or less for the rare pion decay.

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NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

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