Constraint on rho-bar, eta-bar from B to K*pi

A linear CKM relation, $\bar\eta= \tan\Phi_{3/2}(\bar\rho-0.24\pm 0.03)$, involving a $1\sigma$ range for $\Phi_{3/2}$, $20^\circ < \Phi_{3/2} < 115^\circ$, is obtained from $B^0\to K^*\pi$ amplitudes measured recently in Dalitz plot analyses of $B^0\to K^+\pi^-\pi^0$ and $B^0(t)\to K_S\pi^+\pi^-$. This relation is consistent within the large error on $\Phi_{3/2}$ with other CKM constraints which are unaffected by new $b\to s\bar q q$ operators. Sensitivity of the method to a new physics contribution in the $\Delta S=\Delta I=1$ amplitude is discussed.