Search for the B→Y(4260)K , Y(4260)→J/ψπ+π− decays
We report the results of a search for the B → Yð4260ÞK, Yð4260Þ → J=ψπþπ− decays. This study is based on a data sample corresponding to an integrated luminosity of 711 fb−1, collected at the ϒð4SÞ resonance with the Belle detector at the KEKB asymmetric-energy eþe− collider. We investigate the J=ψπþπ− invariant mass distribution in the range 4.0 to 4.6 GeV=c2 using both Bþ → J=ψπþπ−Kþ and B0 → J=ψπþπ−K0 S decays. We find excesses of events above the background levels, with significances of 2.1 and 0.9 standard deviations for charged and neutral B → Yð4260ÞK decays, respectively, taking into account the systematic uncertainties. These correspond to upper limits on the product of branching fractions, BðBþ → Yð4260ÞKþÞ × BðYð4260Þ → J=ψπþπ−Þ < 1.4 × 10−5 and BðB0 → Yð4260ÞK0Þ × BðYð4260Þ → J=ψπþπ−Þ < 1.7 × 10−5 at the 90% confidence level.
Physical Review D
Digital Object Identifier (DOI)