Anatomy of B0sd -> J/psi f0(980)

This decay offers an interesting experimental alternative for the search of CP-violating New-Physics contributions to Bs0 ???Bs0 mixing. As the hadronic structure of the f0(980) has not yet been settled, we take a critical look at the implications for the relevant observables and address recent experimental data. It turns out that the effective lifetime of Bs0->J/psi f0(980) and its mixing-induced CP asymmetry S are quite robust with respect to hadronic effects and thereby allow us to search for a large CP-violating Bs0 ???Bs0 mixing phase ??s , which is tiny in the Standard Model. However, should small CP violation be found in this decay, it will be crucial to constrain hadronic corrections in order to distinguish possible New-Physics effects from the Standard Model. We point out that this decay is a key channel in this respect and discuss the physics potential of this decay.