Off-diagonal helicity density matrix elements for heavy vector mesons inclusively produced in NN,γN and ℓN interactions

Final state interactions in quark fragmentation may give origin to non zero values of the off-diagonal element ρ1,−1 of the helicity density matrix of vector mesons V produced in current jets, with a large energy fraction xE; the value of ρ1,−1(V) is related to the hard constituent dynamics and tests unusual properties of it. Some recent data on φ, K∗ and D∗ produced in e+e− annihilations at LEP show such effects. Predictions are given here for ρ1,−1 of heavy mesons produced in nucleon-nucleon, γ-nucleon and ℓ-nucleon interactions.