The b quark fragmentation fractions at LHCb and meson decays with heavy quark spectators

We study the current estimates of B-c -> B-s pi to extract the fragmentation fraction f(c)/f(s) at the LHCb. A rather robust estimate of Br(B-c -> B-s pi) based on factorization and lattice results for the form factor gives f(c)/f(s) similar to 0.056 with