First measurements of absolute branching fractions of the Ξc+ baryon at Belle

We present the first measurements of the absolute branching fractions of Xi(+)(c) decays into Xi(-)pi(+)pi(+) and pK(-)pi(+) final states. Our analysis is based on a data set of (772 +/- 11) x 10(6) B (B) over bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) collider. We measure the absolute branching fraction of (B) over bar (0) -> (Lambda) over bar (-)(c)Xi(+)(c) with the Xi(+)(c) recoiling against (Lambda) over bar (- )(c)in (B) over bar (0) decays resulting in B((B) over bar (0) -> (Lambda) over bar (-)(c)Xi(+)(c)) = [1.16 +/- 0.42(stat.) +/- 0.15(syst.)] x 10(-3). We then measure the product branching fractions B((B) over bar (0) -> (Lambda) over bar (-)(c)Xi(+)(c))B(Xi(+)(c) -> Xi(-)pi(+)pi(+)) and B((B) over bar (0) -> (Lambda) over bar (-)(c)Xi(+)(c))B(Xi(+)(c) -> pK(-)pi(+)). Dividing these product branching fractions by (B) over bar (0) -> (Lambda) over bar (-)(c)Xi(+)(c) yields B(Xi(+)(c) -> Xi(-)pi(+)pi(+)) = [2.86 +/- 1.21(stat.) +/- 0.38(syst.)]% and B(Xi(+)(c) -> pK(-)pi(+)) = [0.45 +/- 0.21(stat.) +/- 0.07(syst.)]%. Our result for B(Xi(+)(c) -> Xi(-)pi(+)pi(+)) can be combined with Xi(+)(c) branching fractions measured relative to Xi(+)(c) -> Xi(-)pi(+)pi(+) to set the absolute scale for many Xi(+)(c) branching fractions.