SEARCH FOR PENTAQUARKS AND STUDY OF D_(sJ) MESONS AT BELLE

摘要

We search for the strange pentaquark using kaon interactions in the detector material and obtain an upper limit on the ratio of Θ~+ and Λ(1520) yields σ(Θ~+)/σ(Λ(1520)) < 2% assuming Θ~+ is narrow. We report also on searches for the strange and charmed pentaquarks in B meson decays. These results are obtained from a 155 fb~(-1) data sample collected with the Belle detector near the Υ(4S) resonance, at the KEKB. We report improved measurement of the decays B → DD_(sJ)(2317) and B → DD_(sJ)(2460) based on 274 x 10~6 BB events. We measure the ratio of D_(sJ)(2460) → D_sγ and D_s~* π~0 branchings to be 0.43 ± 0.08 ± 0.04 and set upper limits for its other decay channels. An angular analysis supports the hypothesis that the D_(sJ)(2317) and D_(sJ)(2460) are a 0~+ and 1~+ states, respectively. A new decay channel B → D~*D_(sJ)(2460) is observed. A strict upper limit is set on production of a new D_(sJ) meson observed by SELEX: σ(D_(sJ)(2632))/σ(D_(sJ)(2573)) < 2%.