  The absence of second class currents together with the assumption of
factorization for non-leptonic B decays provide new constraints on CP
observables in decay B to a0(980)(to eta pi) pi. The kinematics of this decay
do not allow interference between the oppositely charged resonances in the
Dalitz plot as in B0 to rho(770)pi. Nonetheless, under the assumption of
factorization,the a0pi two-body time-dependent isospin analysis leads to a more
robust extraction of the angle alpha than in the rhopi isospin-pentagon
analysis. The absence of second class currents might lead to enhanced direct CP
violation and/or allows for a test of some assumptions made in the alpha
analysis in other decays like B to a0rho, B to b1(1235)pi, B to a0 a0, B to
eta(eta')pipi and B to b1 a0. The effects from non-factorizable contributions
on the determination of alpha are estimated by means of a numerical study.
