2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/203744We report a search for the decay $B^0 \to J/ψϕ$, using a sample of 657 $\times 10^6$ $B\bar{B}$ 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 $\mathcal{B}(B^0 \to J/ψϕ) < 9.4 \times 10^{-7}$ at 90% confidence level.5 pages, 2 figures, 3 tables, submitted to PRD(RC)High Energy Physics - Experimenttext