De Lucia, E (reprint author), Ist Nazl Fis Nucl, Lab Nazl Frascati, Via E Fermi 40, I-00044 Frascati, Italy.
We have measured the absolute branching ratio K(+) -> pi(+)pi(0)(gamma) decay, using similar to 20 million tagged K(+) mesons collected with the KLOE detector at DA Phi NE, 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(+)pi(0)(gamma)) = 0.2065 +/- 0.0005(stat) +/- 0.0008(syst.) (C) 2008 Elsevier B.V. All rights reserved.