Rotation-invariant relations in vector meson decays into fermion pairs
Pietro Faccioli, Carlos Lourenco, Joao Seixas
TL;DR
The covariance properties of angular momentum eigenstates imply the existence of a rotation-invariant relation among the parameters of the difermion decay distribution of inclusively observed vector mesons, which is equivalent to the dynamical condition that the dilepton is always produced transversely polarized with respect to quantization axes belonging to the production plane.
Abstract
The rotational properties of angular momentum eigenstates imply the existence of a frame-independent relation among the parameters of the decay distribution of vector mesons into fermions. This relation is a generalization of the Lam-Tung identity, a result specific to Drell-Yan production in perturbative QCD, here shown to be equivalent to the dynamical condition that the dilepton always originates from a transversely polarized photon.