First observation and measurement of the resonant structure of the lambda_b->lambda_c pi-pi+pi- decay mode

We present the first observation of the lambda_b->lambda_c pi-pi+pi- decay using data from an integrated luminosity of approximately 2.4 fb-1 of ppbar collisions at ECM=1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. We also present the first observation of the resonant decays lambda_b->sigma_c(2455)0 pi+pi- ->lambda_c pi-pi+pi-, lambda_b->sigma_c(2455)++ pi-pi- ->lambda_c pi-pi+pi-, lambda_b->lambda_c(2595)+ pi- ->lambda_c pi-pi+pi- and lambda_b->lambda_c(2625)+ pi- ->lambda_c pi-pi+pi-, and measure their relative branching ratios.