First hint of non-standard CP violation from B --> Phi K_S decay

Abstract

We comment on the implications of the recently measured CP asymmetry in B --> Phi K_S decay. The data disfavor the Standard Model at 2.7 sigma and -if the trend persists in the future with higher statistics - require the existence of CP violation beyond that in the CKM matrix. In particular, the b --> s bar{s} s decay amplitude would require new contributions of comparable size to the Standard Model ones with an order one phase. While not every model can deliver such a large amount of CP and flavor violation, those with substantial FCNC couplings to the Z can reproduce the experimental findings.

Comments: references added and minor text changes; conclusions unchanged; PRD version; 5 pages, 2 figures, uses espcrc2.sty