Search for B decays to final states with the η c meson

We report a search for B decays to selected final states with the η c meson: B ± → K ± η c π + π −, B ± → K ± η c ω, B ± → K ± η c η and B ± → K ± η c π 0. The analysis is based on 772 × 106 $$ B\overline{B} $$ 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 $$ {D}^0{\overline{D}}^{\ast 0}-{\overline{D}}^0{D}^{\ast 0},{D}^0{\overline{D}}^0+{\overline{D}}^0{D}^0 $$ and $$ {D}^{\ast 0}{\overline{D}}^{\ast 0}+{\overline{D}}^{\ast 0}{D}^{\ast 0} $$ 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.