Calculating B-meson decay constants using domain-wall light quarks and nonperturbatively tuned relativistic b-quarks

We calculate B-physics quantities using the RBC/UKQCD 2+1 flavor domain-wall plus Iwasaki lattices and the relativistic heavy quark action developed by Christ, Li and Lin. After tuning these parameters nonperturbatively, we present our preliminary results for the calculation of the decay constants f_B and f_{B_s} analyzing data at two lattice spacings of a ~ 0.11 fm and a ~ 0.08 fm.