B-S(0)-(B)over-bar(S)(0) mixing and B -> pi K decays in stringy leptophobic Z '

초록

We consider a leptophobic Z' scenario in a flipped SU(5) grand unified theory obtained from heterotic string theory. We show that the allowed Z' mass, flavor conserving and flavor changing couplings of the Z' to the down-type quarks are strongly constrained by the mass difference in B-S-(B) over bar (S) system and the four branching ratios of B -> pi K decays. It is shown that even under these constraints large deviations in direct and/or indirect CP asymmetries of B -> pi K decays from the SM expectations are allowed. Especially it is possible to accommodate the apparent puzzling data in B -> pi K CP asymmetries. (C) 2008 Elsevier B.V. All rights reserved.

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