Determining weak phase gamma and probing new physics in b->s transitions from B->eta(eta')K

Abstract

We present a method of determining weak phase \gamma in the Cabibbo-Kobayashi-Maskawa matrix from decays B->\eta K, \eta' K$alone.Givenalargeratiobetweencolor-suppressedandcolor-allowedtreediagramsextractedfromglobal\pi \pi (K)fits,\gamma isdeterminedfromthecurrentdataof{\eta }^{\prime }KandtheresultisinagreementwiththeglobalStandardModel(SM)fits.However,asmallerratiofromfactorizationbasedcalculationsgives$\gamma\sim 90^\circ$. New physics beyond the SM can be singled out if\gamma obtained in \eta^{(')} K modes is significantly different than the ones from other modes or other approaches. The effective value of \gamma from \eta' K is very sensitive to new physics contributions and can be used to extract new physics parameters for a class of models which do not give contributions to strong phases significantly.

Comments: 18 pages, 2 figures, version to appear in Eur.Phys.J.C