Over the last few years, the B factories have established the Cabbibo-Kobayashi-Maskawa mechanism of CP violation in the Standard Model through the study of the decays of B mesons. The focus of Belle and BaBar has now expanded to the search for signatures of new physics beyond the Standard Model, particularly through examination of flavor-changing neutral-current transitions, which proceed through diagrams involving virtual loops. These decays are suppressed in the Standard Model, increasing sensitivity to new-physics effects but decreasing branching fractions. Exploiting large and growing datasets, BaBar and Belle have made many measurements in loop decays where a b quark transitions to an s quark, observing hints of possible deviations from Standard Model expectations in CP-violating measurements.

We present measurements of branching fractions and CP-violating asymmetries for neutral B meson decays to two-body final states of charged pions and kaons. The results are obtained from a data sample of about 88 million[Upsilon](4S)[yields] B[bar B] decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. From a time-independent fit we measure the charge-averaged branching fractions[Beta](B[sup 0][yields][pi][sup+][pi][sup -])= (4.7[+-] 0.6[+-] 0.2) x 10[sup -6] and[Beta](B[sup 0][yields] K[sup+][pi][sup -])= (17.9[+-] 0.9[+-] 0.7) x 10[sup -6], where the first uncertainty is statistical and the second is systematic; the 90% confidence level upper limit[Beta](B[sup 0][yields] K[sup+]K[sup -])

Over the last few years, the B factories have established the Cabbibo-Kobayashi-Maskawa mechanism of CP violation in the Standard Model through the study of the decays of B mesons. The focus of Belle and BaBar has now expanded to the search for signatures of new physics beyond the Standard Model, particularly through examination of flavor-changing neutral-current transitions, which proceed through diagrams involving virtual loops. These decays are suppressed in the Standard Model, increasing sensitivity to new-physics effects but decreasing branching fractions. Exploiting large and growing datasets, BaBar and Belle have made many measurements in loop decays where a b quark transitions to an s quark, observing hints of possible deviations from Standard Model expectations in CP-violating measurements.

We present preliminary measurements of branching fractions and direct CP violating asymmetries in charmless two-body B decays, obtained with the BABAR detector using a sample of 227M {Upsilon}(4S) {yields} B{bar B} decays. We report the first observation of B{sup 0} {yields} K{sup 0}{bar K}{sup 0} and the first observation of direct CP violation in B{sup 0} {yields} K{sup +}{pi}{sup -} decays.