${\bar{B}}_s\to f_0(980)$ form factors and the width effect from light-cone sum rules

Abstract

In this paper we calculate the ${\bar{B}}_s\to f_0(980)$ form factors from light-cone sum rules with $B$ meson DAs. With adopting the quark-antiquark configuration of light scalar mesons,the high twist two-particle and the three-particle contributions are found to be $\sim 25\%$ individual, and totally they give about $50\%$ correction to certain form factors in the considered energy regions. We further explore the light-cone sum rules approach to study the $S-$wave ${\bar{B}}_s\to KK$ form factors,the $f_0+f_0^{\prime }+f_0^{\prime \prime }$ resonance model is proposed and the result shows that the background effect from $f_0^{\prime }+f_0^{\prime \prime }$ accounts $\sim 5\%$. As a by-product, we extract the strong coupling $|g_{f_{0}KK}|=1.08_{-0.14}^{+0.05}$ GeV with taking the ${\bar{B}}_s\to f_0(980)$ form factors calculated previous under the narrow width approximation.

Comments: 15 pages, 9 figures, 2 tables; accepted version for publication in the Eur.Phys.J.C