Scalar mesons: in search of the lightest glueball

According to the QCD expectations the lightest glueball should be a scalar particle (JPC=0++). Different scenarios have been considered for a classification of these states but – despite considerable progress in recent years – the experimental basis for various parameters is still rather weak. We present a new analysis of the elastic and charge exchange ππ scattering between 1000 and 1800 MeV. A unique solution is selected which shows clear evidence for f0(1500) and a broad state (σ or “f0″(1000)), but there is no evidence for f0(1370) at a level of ≳10% branching ratio to ππ. Arguments in favour of the broad state to be a glueball are summarized.