Measurement of Branching Fractions of Color-Suppressed Decays of the B-bar0 meson to D(*)0π0, D(*)0η, D(*)0ω and D0η'

Using a sample of 88.8x106 B-bar events collected with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center, we measure the branching fractions of seven colorsuppressed Β-meson decays: Β(Bbar0 -> D0π0) = (2.9 +/- 0.2(stat.) +/- 0.3(syst.))x10-4, Β(Bbar0 -> D*0π0) = (2.9 +/- 0.4(stat.) +/- 0.5(syst.))x10-4, Β(Bbar0 -> D0η) = (2.5 +/- 0.2(stat.) +/- 0.3(syst.))x10-4, Β(Bbar0 -> D*0η) = (2.6 +/- 0.4(stat.) +/- 0.4(syst.))x10-4, Β(Bbar0 -> D0ω) = (3.0 +/- 0.3(stat.) +/- 0.4(syst.))x10-4, Β(Bbar0 -> D*0ω) = (4.2 +- 0.7(stat.) +/- 0.9(syst.)) x 10-4, and Β(Bbar0 -> D0η') = (1.7 +/- 0.4(stat.) +/- 0.2(syst.))x10-4. We set the 90% confidence-level upper limit: Β(Bbar0 -> D*0η') < 2.6x10-4. The channels Bbar0 -> D*0η, D*0ω, and Dη' are seen with more than five-sigma statistical significance. All of these branching fractions are significantly larger than theoretical expectations based on the ''naive'' factorization model