Search for B decays to final states with the η_c meson

Abstract: We report a search for B decays to selected final states with the η_c meson: B^± → K^±η_cπ⁺π⁻, B^± → K^±η_cω, B^± → K^±η_cη and B^± → K^±η_cπ⁰. The analysis is based on 772 × 10⁶BB¯$$ B\overline{B} $$ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e⁺e⁻ collider. We set 90% confidence level upper limits on the branching fractions of the studied B decay modes, independent of intermediate resonances, in the range (0.6–5.3) × 10⁻⁴. We also search for molecular-state candidates in the (Formula presented.) and (Formula presented.) combinations, neutral partners of the Z(3900)^± and Z(4020)^±, and a poorly understood state X(3915) as possible intermediate states in the decay chain, and set 90% confidence level upper limits on the product of branching fractions to the mentioned intermediate states and decay branching fractions of these states in the range (0.6–6.9) × 10⁻⁵.