Measurement of the absolute branching ratio of the K+→π+π0(γ) decay with the KLOE detector

F. Ambrosino, A. Antonelli, M. Antonelli, F. Archilli, C. Bacci, P. Beltrame, G. Bencivenni, S. Bertolucci, C. Bini, C. Bloise, S. Bocchetta, F. Bossi (+66 others)
2008 Physics Letters B  
We have measured the absolute branching ratio of the K+ -> pi+ pi0 (gamma) decay, using about 20 million tagged K+ mesons collected with the KLOE detector at DAFNE, the Frascati phi-factory. Signal counts are obtained from the fit of the distribution of the momentum of the charged decay particle in the kaon rest frame. The result, inclusive of final-state radiation, is BR(K+ -> pi+ pi0 (gamma))=0.2065+/-0.0005_stat+/- 0.0008_syst.
doi:10.1016/j.physletb.2008.07.070 fatcat:js5xo3z6z5ea7c5jqoh6f2gyru