${\chi }_{c2}\to \rho \rho$ and the $rho$ polarization in massless perturbative QCD: how to test the distribution amplitudes

Mauro Anselmino, Francesco Murgia

We compute the helicity density matrix of $\rho$ vector mesons produced in the two-body decays of polarized ${\chi }_{c2}$'s in the framework of massless perturbative QCD. The ${\chi }_{c2}$'s ar…