$γγ$ physics with the KLOE experiment
hep-ex
/ Authors
The KLOE-2 Collaboration, F. Archilli, D. Babusci, D. Badoni, I. Balwierz, G. Bencivenni, C. Bini, C. Bloise, V. Bocci, F. Bossi
and 60 more authors
P. Branchini, A. Budano, S. A. Bulychjev, P. Campana, G. Capon, F. Ceradini, P. Ciambrone, E. Czerwinski, E. Dane, E. De Lucia, G. De Robertis, A. De Santis, G. De Zorzi, A. Di Domenico, C. Di Donato, D. Domenici, O. Erriquez, G. Fanizzi, G. Felici, S. Fiore, P. Franzini, P. Gauzzi, S. Giovannella, F. Gonnella
/ Abstract
The processes $e^+e^-\to e^+e^-X$, with $X$ being either the $η$ meson or $π^0π^0$, are studied at DA$Φ$NE, with $e^+e^-$ beams colliding at $\sqrt{s}\simeq1$ GeV, below the $φ$ resonance peak. The data sample is from an integrated luminosity of 240 pb$^{-1}$, collected by the KLOE experiment without tagging of the outgoing $e^+e^-$. Preliminary results are presented on the observation of the $γγ\toη$ process, with both $η\toπ^+π^-π^0$ and $η\toπ^0π^0π^0$ channels, and the evidence for $γγ\toπ^0π^0$ production at low $π^0π^0$ invariant mass.