CP violation in B mesons using Dalitz plot asymmetries

We study CP violation in $B\to K^* \ell^+\ell^-$ using generalized Dalitz plot asymmetries in the angular distribution. These new kind of asymmetries are constructed by adding B and ${\bar B}$ events, and do not require flavor or time tagging, nor is the presence of strong phases needed. Using this method one requires about $2 \times 10^8/\eta$ B's to measure the CP violating parameter $\eta$ in the Standard model. The two--Higgs doublet model requires only $10^7$ B's to constrain parameters better than done by the electric dipole moment of the neutron.