Spin alignment measurements of the K*{sup 0}(892) and {phi}(1020) vector mesons in heavy ion collisions at {radical}(s{sub NN})=200 GeV

We present the first spin alignment measurements for the K*{sup 0}(892) and {phi}(1020) vector mesons produced at midrapidity with transverse momenta up to 5 GeV/c at {radical}(s{sub NN})=200 GeV at RHIC. The diagonal spin-density matrix elements with respect to the reaction plane in Au+Au collisions are {rho}{sub 00}=0.32{+-}0.04 (stat) {+-} 0.09 (syst) for the K*{sup 0} (0.8<p{sub T}<5.0 GeV/c) and {rho}{sub 00}=0.34{+-}0.02 (stat) {+-} 0.03 (syst) for the {phi} (0.4<p{sub T}<5.0 GeV/c) and are constant with transverse momentum and collision centrality. The data are consistent with the unpolarized expectation of 1/3 and thus no evidence is found for the transfer of the orbital angular momentum of the colliding system to the vector-meson spins. Spin alignments for K*{sup 0} and {phi} in Au+Au collisions were also measured with respect to the particle's production plane. The {phi} result, {rho}{sub 00}=0.41{+-}0.02 (stat) {+-} 0.04 (syst), is consistent with that in p+p collisions, {rho}{sub 00}=0.39{+-}0.03 (stat) {+-} 0.06 (syst), also measured in this work. The measurements thus constrain the possible size of polarization phenomena in the production dynamics of vector mesons.