{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.101350.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/777248"}},{"@id":"https://doi.org/10.1103/PhysRevC.77.061902","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"STAR Collaboration"},"creator":{"@type":"Organization","name":"STAR Collaboration"},"datePublished":"2021","description":"We present the first spin alignment measurements for the $K^{*0}(892)$ and $\\phi(1020)$ vector mesons produced at midrapidity with transverse momenta up to 5 GeV/$c$ at $\\sqrt{s_{NN}}=200$ GeV at RHIC. The diagonal spin-density matrix elements with respect to the reaction plane in $Au+Au$ collisions are $\\rho_{00}=0.32 \\pm 0.04 (\\mbox{stat}) \\pm 0.09 (\\mbox{sys})$ for the $K^{*0}$ ($0.8 < p_{T} < 5.0$ GeV/$c$) and $\\rho_{00}=0.34 \\pm 0.02 (\\mbox{stat}) \\pm 0.03 (\\mbox{sys})$ for the $\\phi$ ($0.4 < p_{T} < 5.0$ 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 $K^{*0}$ and $\\phi$ in $Au+Au$ collisions were also measured with respect to the particle\u2019s production plane. The $\\phi$ result, $\\rho_{00}=0.41 \\pm 0.02 (\\mbox{stat}) \\pm 0.04 (\\mbox{sys})$, is consistent with that in $p+p$ collisions, $\\rho_{00}=0.39 \\pm 0.03 (\\mbox{stat}) \\pm 0.06 (\\mbox{sys})$, also measured in this work. The measurements thus constrain the possible size of polarization phenomena in the production dynamics of vector mesons.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.101350.v1/t1","@type":"Dataset","description":"The spin-density matrix elements $\\rho_{00}$ with respect to the reaction plane in midcentral $Au+Au$ collisions at $\\sqrt{s_{NN}}=200$ GeV versus $p_{T}$...","name":"Table 1"},{"@id":"https://doi.org/10.17182/hepdata.101350.v1/t2","@type":"Dataset","description":"The dependence of $\\rho_{00}$ with respect to the reaction plane on the number of participants at midrapidity in $Au+Au$ collisions...","name":"Table 2"},{"@id":"https://doi.org/10.17182/hepdata.101350.v1/t3","@type":"Dataset","description":"The spin-density matrix elements $\\rho_{00}$ with respect to the production plane in midcentral $Au+Au$ and $p+p$ collisions at $\\sqrt{s_{NN}}=200$ GeV...","name":"Table 3"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins777248?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/101350"}],"inLanguage":"en","name":"Spin alignment measurements of the $K^{*0}(892)$ and $\\phi(1020)$ vector mesons in heavy ion collisions at $\\sqrt{s}_{NN} = 200$ GeV","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins777248?version=1","version":1}