SEMINAR    Thursday October 19th, 2006 - h. 15:00 Aula Seminari    P. Wang (IHEP - Beijing) Universal phase between strong and EM interactions in quarkonium decays. Abstract It has been known that in all two-body J/psi decays, the strong and electromagnetic (EM) interactions are orthogonal. The experimental data from BES and more recent ones from CLEO indicate that this holds in psi' and OZI suppressed psi" decays too and the phase must be -90 degree. The talk will analyze the experimental evidence of this new empirical law and discusse its possible implications. It leads to the conjucture that in the decays of quarkonium 1^{--} states, the relative phase between strong and EM amplitudes is universally at -90 degree. The talk also discusses the so-called rho-pi puzzle in charmonium decays and the solution which gets support from new experimental data.