Diagnostic for new physics in $B\to \pi K$ decays

Abstract

A recent analysis of $B\to \pi K$ decays concludes that present data do not clearly indicate whether (i) the standard model (or $\Delta I=0$ new physics) is sufficient, or (ii) $\Delta I=1$ new physics is needed. We show that these two possibilities can be distinguished by whether a sum rule relating the CP asymmetries of the four $B\to \pi K$ decays is valid. If case (i) is favored, the sum rule holds, and one predicts $A_{CP}({\pi }^0{K}^0)=-0.15$, while in case (ii) fits to new physics involving large values of a color-suppressed tree amplitude entail $A_{CP}({\pi }^0{K}^0)=-0.03$. The current experimental average $A_{CP}({\pi }^0{K}^0)=-0.01\pm 0.10$ must be measured a factor of at least three times more precisely in order to distinguish between the two cases.

10 pages, no figures. Submitted to Physics Letters B. Slight clarification added

References in corpus (3)

• Benchmarks for the New-Physics Search through CP Violation in B^0->pi^0 K_S
• Is There Still a B -> pi K Puzzle?
• Implications for CP asymmetries of improved data on $B\to K^0{\pi }^0$