Search for the Z1(4050)+ and Z2(4250)+ states in Bˉ0→χc1K−π+ and B+→χc1K0Sπ+

Abstract

We search for the Z1(4050)+ and Z2(4250)+ states, reported by the Belle Collaboration, decaying to χc1π+ in the decays B̅ 0→χc1K-π+ and B+→χc1KS0π+ where χc1→J/ψγ. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e+e- collider operating at center-of-mass energy 10.58 GeV, and correspond to an integrated luminosity of 429  fb-1. In this analysis, we model the background-subtracted, efficiency-corrected χc1π+ mass distribution using the Kπ mass distribution and the corresponding normalized Kπ Legendre-polynomial moments, and then test the need for the inclusion of resonant structures in the description of the χc1π+ mass distribution. No evidence is found for the Z1(4050)+ and Z2(4250)+ resonances, and 90% confidence level upper limits on the branching fractions are reported for the corresponding B-meson decay modes.