Abstrakt
We present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay Lambda(+)(c) -> p eta' with eta' -> eta pi(+)pi(-), using a data sample cor- responding to an integrated luminosity of 981 fb(-1), collected by the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. A significant Lambda(+)(c) -> p eta' signal is observed for the first time with a signal significance of 5.4 sigma.
The relative branching fraction with respect to the normalization mode Lambda(+)(c) -> pK(-) pi(+) is measured to be B(Lambda(+)(c) -> p eta')/B(Lambda(+)(c) -> pK(-) pi(+)) = (7.54 +/- 1.32 +/- 0.73) x 10(-3), where the uncertainties are statistical and systematic, respectively. Using the world-average value of B(Lambda(+)(c) -> pK(-)pi(+)) = (6.28 +/- 0.32) x 10(-2), we obtain B(Lambda(+)(c) -> p eta') = (4.73 +/- 0.82 +/- 0.46 +/- 0.24) x 10(-4), where the uncertainties are statistical, systematic, and from B(Lambda(+)(c) -> pK(-) pi(+)), respectively.