CP asymmetries in B̄ → K̄*( → K̄π)l̄land untagged B̄s,Bs→ ϕ( →K+K−)l̄ldecays at NLO

Abstract

The decay → *( → π)l offers great opportunities to explore the physics at and above the electroweak scale by means of an angular analysis. We investigate the physics potential of the seven CP asymmetries plus the asymmetry in the rate, working at low dilepton mass using QCD factorization at next-to leading order (NLO). The b → s CP asymmetries are doubly Cabibbo-suppressed ≲1% in the Standard Model and its extensions where the CKM matrix is the only source of CP violation. Three CP asymmetries are T-odd, and can be (1) in the presence of non-standard CP violation. The T-even asymmetries can reach (0.1), limited by the small strong phases in the large recoil region. We furthermore point out an easy way to measure CP phases from time-integrated, untagged d, Bd → K*( → K0π0)l and s, Bs → ϕ( → K+K−)l decays. Analyses of these CP asymmetries can rule out, or further support the minimal description of CP violation through the CKM mechanism. Experimental studies are promising for (super) flavor factories and at hadron colliders.