{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.98962.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/771169"}},{"@id":"https://doi.org/10.1103/PhysRevC.77.034910","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"STAR Collaboration"},"creator":{"@type":"Organization","name":"STAR Collaboration"},"datePublished":"2021","description":"Photoproduction reactions occur when the electromagnetic field of a relativistic heavy ion interacts with another heavy ion. The STAR collaboration presents a measurement of $\\rho^{0}$ and direct $\\pi^{+}\\pi^{-}$ photoproduction in ultra-peripheral relativistic heavy ion collisions at $\\sqrt{s_{NN}}$=200 GeV. We observe both exclusive photoproduction and photoproduction accompanied by mutual Coulomb excitation. We find a coherent cross-section of $\\sigma(AuAu \\rightarrow Au^{*}Au^{*} \\rho^{0})$ = 530 $\\pm$ 19 (stat.) $\\pm$ 57 (syst.) mb, in accord with theoretical calculations based on a Glauber approach, but considerably below the predictions of a color dipole model. The $\\rho^{0}$ transverse momentum spectrum ( $p_{T}^{2}$ ) is fit by a double exponential curve including both coherent and incoherent coupling to the target nucleus; we find $\\sigma_{inc}/\\sigma_{coh}$ = 0.29 $\\pm$ 0.03 (stat.) $pm$ 0.08 (syst.). The ratio of direct $\\pi^{+}\\pi^{-}$ to $\\rho^{0}$ production is comparable to that observed in $\\gamma p$ collisions at HERA, and appears to be independent of photon energy. Finally, the measured $\\rho^{0}$ spin helicity matrix elements agree within errors with the expected s-channel helicity conservation.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t1","@type":"Dataset","description":"ZDC spectra obtained with the minimum bias sample after the $\\rho^{0}$ selection cuts are applied, and fit with three Gaussians....","name":"Figure 2 a"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t2","@type":"Dataset","description":"ZDC spectra obtained with the minimum bias sample after the $\\rho^{0}$ selection cuts are applied, and fit with three Gaussians....","name":"Figure 2 b"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t3","@type":"Dataset","description":"The invariant mass distribution for the coherently produced $\\rho^{0}$ candidates from the minimum bias sample with the cut on the...","name":"Figure 3 a"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t4","@type":"Dataset","description":"The invariant mass distribution for the coherently produced $\\rho^{0}$ candidates obtained from the topology sample with the cut on the...","name":"Figure 3 b"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t5","@type":"Dataset","description":"The ratio |B/A| as a function of $y_{\\rho^{0}}$ for the minimum bias data, obtained by fitting Eq.3 to the invariant...","name":"Figure 4"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t6","@type":"Dataset","description":"Coherent $\\rho^{0}$ production cross-section for the minimum bias data set as a function of $y_{\\rho^{0}}$ (black dots) overlaid by the...","name":"Figure 5"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t7","@type":"Dataset","description":"$\\rho^{0}$ production cross-section as a function of the momentum transfer squared $t$, together with the fit of Eq. 5. The...","name":"Figure 6"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t8","@type":"Dataset","description":"Comparison of theoretical predictions to the measured differential cross-section for coherent $\\rho^{0}$ production. The statistical errors are shown by the...","name":"Figure 7"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t9","@type":"Dataset","description":"Projections of the two dimensional efficiency corrected $\\Phi_{h}$ vs $cos(\\Theta_{h})$ distributions obtained with the minimum bias data set. The solid...","name":"Figure 8 a"},{"@id":"https://doi.org/10.17182/hepdata.98962.v1/t10","@type":"Dataset","description":"Projections of the two dimensional efficiency corrected $\\Phi_{h}$ vs $cos(\\Theta_{h})$ distributions obtained with the minimum bias data set. The solid...","name":"Figure 8 b"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins771169?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/98962"}],"inLanguage":"en","name":"rho^0 Photoproduction in Ultra-Peripheral Relativistic Heavy Ion Collisions with STAR","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins771169?version=1","version":1}