Measurement of the absolute branching ratio of the $K^{+}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^{+}({\hat{I}}^3)$ decay with the KLOE detector

Abstract

The absolute branching ratio of the $K^{+}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^{+}({\hat{I}}^3)$ decay, inclusive of final-state radiation, has been measured using $\sim$17 million tagged $K^{+}$ mesons collected with the KLOE detector at DA$\hat{I}¦$NE, the Frascati $\ddot{I}•$-factory. The result is: \[ BR(K^+ \rightarrow π^+π^-π^+(γ)) = 0.05565 \pm 0.00031_{stat} \pm 0.00025_{syst} \] a factor $\simeq$ 5 more precise with respect to the previous result. This work completes the program of precision measurements of the dominant kaon branching ratios at KLOE.

13 pages, 2 figures, to be submitted to Physics Letters B