Scalar resonance effects on the B_s - \bar B_s mixing angle

Abstract

The $B_s^0 \to J/ψϕ$ and $B_s^0 \to J/ψf_0(980)$ decays are analyzed within generalized QCD factorization including all leading-order corrections in $\alphas$. We point out that the ratio of our calculated widths, $Γ(B_s^0\to J/ψf_0(980), f_0(980)\to π^+π^-)/ Γ(B_s^0 \to J/ψϕ,ϕ\to K^+K^-)$, strongly indicates that $S$-wave effects in the $f_0(980)$'s daughter pions or kaons cannot be ignored in the extraction of the $B_s-\bar{B}_s$ mixing angle, $-2β_s$, from the $B_s^0 \to ϕJ/ψ$ decay amplitudes.

16 pages and 3 figures; revised version due to erroneous discussion of annihilation contribution which led to their over-estimation. Main conclusions are not altered, yet Fig. 2-3 changed; one additional table (Table IX) compares theoretical values to data for branching fractions, asymmetries as well as polarizations. New paragraph about f_0(980) decay constant on page 14. Accepted in PRD