Observation of the D-1(2420) -> D pi(+)pi(-) decays

We report on the first observation of D-1(0)(2420)-> D(0)pi(-)pi(+) and D-1(+)(2420)-> D(+)pi(-)pi(+) decays (where the contribution from the dominant known D-1-> D(*)pi decay mode is excluded) in the B--> D(1)(0)pi(-) and (B) over bar (0)-> D(1)(+)pi(-) decays, respectively. The observation is based on 15.2x10(7) B (B) over bar events collected with the Belle detector at the KEKB collider. We also set 90% confidence level upper limits for the branching fractions of the four following decays: B--> D(1)(0)pi(-), D-1(0)-> D(*0)pi(-)pi(+), (B) over bar (0)-> D(1)(+)pi(-), D-1(+)-> D(*+)pi(-)pi(+), B--> D-2(*0)(2460)pi(-), D-2(*0)-> D(*0)pi(-)pi(+), (B) over bar (0)-> D-2(*+)(2460)pi(-), D-2(*+)-> D(*+)pi(-)pi(+).