Abstrakt
We present the study of (B) over bar (0) -> Sigma(c)(2455)(0, + +) pi(+/-)(p) over bar decays based on 772 x 10(6) B (B) over bar events collected with the Belle detector at the KEKB asymmetric-energy e(+) e(-) collider. The Sigma(c)(2455)(0, + +) candidates are reconstructed via their decay to Lambda(+)(c)x(-/+) and Lambda(+)(c) decays to pK(-)pi(+), pK(S)(0), and Lambda pi(+) final states.
The corresponding branching fractions are measured to be B((B) over bar (0) -> Sigma(c)(2455)(0)pi(+)(p) over bar) = (1.09 +/- 0.06 +/- 0.07) x 10(-4) and B((B) over bar (0) -> Sigma(c)(2455)(+ +)pi(-)(p) over bar) = (1.84 +/- 0.11 +/- 0.12) x 10(-4), which are consistent with the world average values with improved precision. A new structure is found in the M-Sigma c(2455)0,M- + + pi +/- spectrum with a significance of 4.2 sigma including systematic uncertainty.
The structure is possibly an excited Lambda(+)(c) and is tentatively named Lambda(c)(2910)(+). Its mass and width are measured to be (2913.8 +/- 5.6 +/- 3.8) MeV/c(2) and (51.8 +/- 20.0 +/- 18.8) MeV, respectively.
The products of branching fractions for the Lambda(c)(2910)(+) are measured to be B((B) over bar (0) -> Lambda(c)(2910)(+)(p) over bar) x B(Lambda(c)(2910)(+) -> Sigma(c)(2455)(0)pi(+)) = (9.5 +/- 3.6 +/- 1.6) x 10(-6) and B((B) over bar (0) -> Lambda(c)(2910)(+)(p) over bar) x B(Lambda(c)(2910)(+) -> Sigma(c)(2455)(+ +)pi(-)) = (1.24 +/- 0.35 +/- 0.10) x 10(-5). Here, the first and second uncertainties are statistical and systematic, respectively.