Observation of B[subscript s][superscript 0] → [¯ over D][superscript * 0]ϕ and Search for B[superscript 0 ]→ [¯ over D]{superscript 0]ϕ Decays

Abstract

The first observation of the B[subscript s][superscript 0] → [¯ over D][superscript * 0]ϕ decay is reported, with a significance of more than seven standard deviations, from an analysis of pp collision data corresponding to an integrated luminosity of 3 fb[superscript -1], collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The branching fraction is measured relative to that of the topologically similar decay B[superscript 0]→[¯ over D][superscript 0]π[superscript +]π[superscript -] and is found to be B(B[subscript s][superscript 0]→[¯ D][superscript *0]ϕ)=(3.7±0.5±0.3±0.2)×10[superscript -5], where the first uncertainty is statistical, the second systematic, and the third from the branching fraction of the B[superscript 0]→[¯ over D][superscript 0]π[superscript +]π[superscript -] decay. The fraction of longitudinal polarization in this decay is measured to be f[subscript L]=(73±15±4)%. The most precise determination of the branching fraction for the B[subscript s][superscript 0]→[¯ over D][superscript 0]ϕ decay is also obtained, B(B[subscript s][superscript 0]→[¯ over D][superscript 0]ϕ)=(3.0±0.3±0.2±0.2)×10[superscript -5]. An upper limit, B(B[superscript 0]→[¯ over D][superscript 0]ϕ)<2.0 (2.3)×10[superscript -6}] at 90% (95%) confidence level is set. A constraint on the ω-ϕ mixing angle δ is set at |δ|<5.2° (5.5°) at 90% (95%) confidence level.