The inclusive production of ω and ϕ mesons is studied in the backward region of the interaction of 12 GeV protons with polyethylene, carbon, and copper targets. The mesons are measured in $e^{+}{e}^{-}$ decay channels. The production cross sections of the mesons are presented as functions of rapidity $y$ and transverse momentum $p_T$. The nuclear mass number dependences ($A$ dependences) are found to be $A^{0.710\pm 0.021(\text{stat})\pm 0.037(\text{syst})}$ for ω mesons and $A^{0.937\pm 0.049(\text{stat})\pm 0.018(\text{syst})}$ for ϕ mesons in the region of $0.9<y<1.7$ and $p_T<0.75$ GeV/$c$.

• Received 14 March 2006

DOI:https://doi.org/10.1103/PhysRevC.74.025201