CP violation difference in $B^o$ and $B^\pm$ decays explained No tree-penguin interference in $B^+ \to K^+\pi^o$

Abstract

A new experimental analysis of $B\to K\pi$ decays provides finite experimental values for the contributions from interference terms between the dominant penguin amplitude and the color-favored and color-suppressed tree amplitudes. These results can explain the puzzling failure to see CP violation in $B^\pm\to K\pi$ decays. Tree-penguin interference contributions are commonly believed to be the source of the observed direct CP violation in $B^o\to K^\pm\pi^\mp$ decays. The data show that the color-favored and color-suppressed tree contributions interfere destructively in $B^\pm\to K^\pm\pi^o$ decays and nearly cancel. This suprising cancellation is not predicted by present theory. There is also no prediction for any difference produced by changing the flavor of the spectator quark. Isospin and Pauli effects that change with spectator quark flavor are examined and show using group theory and the color-spun SU(6) algebra how they produce both the near cancellation and the dependence on spectator quark flavor. The standard $B\to K\pi$ analysis which treats tree-penguin interference only in first order has three parameters overdetermined by four experimental branching ratios. Previous analyses confirmed the model but with large errors leaving the values of tree-penguin interference contributions less that two standard deviations from zero. The new analysis finds interference contributions well above the errors.