Looking from the East at an Elephant Trotting West: Direct CP Violation in $B^0$ Decays

Abstract

With the time dependant CP asymmetry in $B_d(t)\to \psi K_S$ well measured, the most powerful method to search for {\em direct} CP violation in $B_d$ decays is to analyze whether the CP asymmetry of other transitions like $B_d(t)\to {\pi }^{+}{\pi }^{-},{\eta }^{\prime }{K}_S$ etc. can be described by a $sin$ term taken from $B_d(t)\to \psi K_S$ and without a cos term. The failure of such a constrained fit would establish direct CP violation (even if no CP asymmetry were observed in these other modes).

Comments: 5 pages, LATEX, no figures; references added and corrected; BABAR data on $B_d(t)\to {\pi }^{+}{\pi }^{-}$ included; text slightly extended to emphasize main point