Evidence for the decay $ \mathrm{B}_{\mathrm{c}}^{+}\to {{\mathrm{J}} \left/ {{\uppsi\;3{\uppi^{+}}2{\uppi^{-}}}} \right.} $

Evidence for the decay $ \mathrm{B}_{\mathrm{c}}^{+}\to {{\mathrm{J}} \left/ {{\uppsi\;3{\uppi^{+}}2{\uppi^{-}}}} \right.} $