J / ψ polarization from fixed-target to collider energies

The determination of the magnitude and “sign” of the J/ψ polarization crucially depends on the reference frame used in the analysis of the data and a full understanding of the polarization phenomenon requires measurements reported in two “orthogonal” frames, such as the Collins-Soper and helicity frames. Moreover, the azimuthal anisotropy can be, in certain… CONTINUE READING