Search for dark photon at NA48/2, and measurement of $\pi^0$ form factor

The NA48/2 experiment at CERN performed a search for the dark photon (A′) via the decay chain π (0) → γA′, A′ → e (+) e (−). Using a sample of ∼ 1.7 · 10(7) neutral pions tagged from and decays collected in 2003-04 no signal is observed. The limits in the plane dark photon mixing parameter ε (2) versus its mass m(A)(′) are reported. The NA62-RK experiment collected, during the 2007 data taking, a large sample of neutral pion Dalitz decays with a trigger optimised for electrons final states with respect to NA48/2 one. We report the measurement of the π (0) electromagnetic transition form factor (TFF) slope parameter (a) based on a sample of decays. The preliminary measured value a = (3.70 ± 0.53( )stat( ) ± 0.36( )syst( )) · 10(−)(2) is compatible with theoretical expectations and previous measurements.