Measurements of the Branching fractions for $B_(s) -> D_(s)pipipi$ and $Lambda_b^0 -> Lambda_c^+pipipi$

Branching fractions of the decays $H_bto H_cpi^-pi^+pi^-$ relative to $H_bto H_cpi^-$ are presented, where $H_b$ ($H_c$) represents B^0-bar($D^+$), $B^-$ ($D^0$), B_s^0-bar ($D_s^+$) and $Lambda_b^0$ ($Lambda_c^+$). The measurements are performed with the LHCb detector using 35${rm pb^{-1}}$ of data collected at $sqrt{s}=7$ TeV. The ratios of branching fractions are measured to be B(B^0-bar -> D^+pi^-pi^+pi^-)/ B(B^0-bar -> D^+pi^-) = 2.38pm0.11pm0.21 B(B^- -> D^0pi^-pi^+pi^-) / B(B^- -> D^0pi^-) = 1.27pm0.06pm0.11 B(B_s^0-bar -> D_s^+pi^-pi^+pi^-) / B(B_s^0-bar -> D_s^+pi^-) = 2.01pm0.37pm0.20 B(Lambda_b^0->Lambda_c^+pi^-pi^+pi^-) / B(Lambda_b^0 -> Lambda_c^+pi^-) = 1.43pm0.16pm0.13. We also report measurements of partial decay rates of these decays to excited charm hadrons. These results are of comparable or higher precision than existing measurements.