Evidence for B-> eta' pi and improved measurements for B-> eta' K
  We report evidence for exclusive two-body charmless hadronic B meson decays B-> eta' pi, and improved measurements of B-> eta' K. The results are obtained from a data sample of 386 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric energy e+e- collider. We measure BF(B-> eta' pi+)=[ 1.76 +0.67-0.62(stat) +0.15-0.14(syst)] x 10^-6 and BF(B-> eta' pi0)=[ 2.79 +1.02-0.96(stat) +0.25-0.34(syst)] x 10^-6. We also report the ratio of BF(B-> eta' K+) / BF(B-> eta' K0) = 1.17 +-0.08(stat) +-0.03(syst) and direct CP asymmetries for the charged modes. 
The Belle Collaboration: J. Schuemann, et al