We report a search for the decay B0→J/ψϕ, using a sample of 657
×106BBˉ pairs collected with the Belle detector at the
Υ(4S) resonance. No statistically significant signal is found and an
upper limit for the branching fraction is determined to be B(B0→J/ψϕ)<9.4×10−7 at 90% confidence level.Comment: 5 pages, 2 figures, 3 tables, submitted to PRD(RC