Local density fluctuations near the QCD critical point has been suggested to exhibit a power-law ... more Local density fluctuations near the QCD critical point has been suggested to exhibit a power-law behavior which can be probed by an intermittency analysis on scaled factorial moment (SFM) in relativistic heavy-ion collisions. The collision energy and centrality dependence of the second-order SFMs are systematically investigated in Au + Au collisions at √ sNN = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV within the UrQMD model. We estimate the noncritical background in the measurement of intermittency and propose a cumulative variable method to effectively remove the background contributions. We further study the effect of particle detection efficiency by implementing the RHIC (STAR) experimental tracking efficiencies in the UrQMD events. A cell-by-cell method is proposed for experimental application of efficiency corrections on SFM. This work can provide a guidance of background subtraction and efficiency correction for the experimental measurement of intermittency in the search of the QCD critical point in heavy-ion collisions.
Isobaric 96 44 Ru+ 96 44 Ru and 96 40 Zr+ 96 40 Zr collisions at √ s nn = 200 GeV have been condu... more Isobaric 96 44 Ru+ 96 44 Ru and 96 40 Zr+ 96 40 Zr collisions at √ s nn = 200 GeV have been conducted at the Relativistic Heavy Ion Collider to circumvent the large flow-induced background in searching for the chiral magnetic effect (cme), predicted by the topological feature of quantum chromodynamics (QCD). Considering that the background in isobar collisions is approximately twice that in Au+Au collisions (due to the smaller multiplicity) and the cme signal is approximately half (due to the weaker magnetic field), we caution that the cme may not be detectable with the collected isobar data statistics, within ∼2σ significance, if the axial charge per entropy density (n 5 /s) and the QCD vacuum transition probability are system independent. This expectation is generally verified by the Anomalous-Viscous Fluid Dynamics (avfd) model. While our estimate provides an approximate "experimental" baseline, theoretical uncertainties on the cme remain large.
BNL-RHIC. Two-dimensional angular correlations of D0-mesons with charged hadrons, projected on de... more BNL-RHIC. Two-dimensional angular correlations of D0-mesons with charged hadrons, projected on delEta and delPhi at sNN−−−sqrt=200GeV in STAR are presented. The correlations are fit with a 2D function containing components to capture the 2D jet-peak (Gaussian on delEta and delPhi), the azimuthal harmonics (dipole, quadrupole), and the constant offset. These fits are performed on the data in the three presented centrality bins, and the evolution of these extracted fit values with centrality discussed. Additionally, the per-trigger, near side yield (i.e. the per-trigger yield in the jet-like peak) is extracted and centrality evolution presented. The results indicate strong interaction of the charm-quark or D0-meson with the medium.
Local density fluctuations near the QCD critical point has been suggested to exhibit a power-law ... more Local density fluctuations near the QCD critical point has been suggested to exhibit a power-law behavior which can be probed by an intermittency analysis on scaled factorial moment (SFM) in relativistic heavy-ion collisions. The collision energy and centrality dependence of the second-order SFMs are systematically investigated in Au + Au collisions at √ sNN = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV within the UrQMD model. We estimate the noncritical background in the measurement of intermittency and propose a cumulative variable method to effectively remove the background contributions. We further study the effect of particle detection efficiency by implementing the RHIC (STAR) experimental tracking efficiencies in the UrQMD events. A cell-by-cell method is proposed for experimental application of efficiency corrections on SFM. This work can provide a guidance of background subtraction and efficiency correction for the experimental measurement of intermittency in the search of the QCD critical point in heavy-ion collisions.
Isobaric 96 44 Ru+ 96 44 Ru and 96 40 Zr+ 96 40 Zr collisions at √ s nn = 200 GeV have been condu... more Isobaric 96 44 Ru+ 96 44 Ru and 96 40 Zr+ 96 40 Zr collisions at √ s nn = 200 GeV have been conducted at the Relativistic Heavy Ion Collider to circumvent the large flow-induced background in searching for the chiral magnetic effect (cme), predicted by the topological feature of quantum chromodynamics (QCD). Considering that the background in isobar collisions is approximately twice that in Au+Au collisions (due to the smaller multiplicity) and the cme signal is approximately half (due to the weaker magnetic field), we caution that the cme may not be detectable with the collected isobar data statistics, within ∼2σ significance, if the axial charge per entropy density (n 5 /s) and the QCD vacuum transition probability are system independent. This expectation is generally verified by the Anomalous-Viscous Fluid Dynamics (avfd) model. While our estimate provides an approximate "experimental" baseline, theoretical uncertainties on the cme remain large.
BNL-RHIC. Two-dimensional angular correlations of D0-mesons with charged hadrons, projected on de... more BNL-RHIC. Two-dimensional angular correlations of D0-mesons with charged hadrons, projected on delEta and delPhi at sNN−−−sqrt=200GeV in STAR are presented. The correlations are fit with a 2D function containing components to capture the 2D jet-peak (Gaussian on delEta and delPhi), the azimuthal harmonics (dipole, quadrupole), and the constant offset. These fits are performed on the data in the three presented centrality bins, and the evolution of these extracted fit values with centrality discussed. Additionally, the per-trigger, near side yield (i.e. the per-trigger yield in the jet-like peak) is extracted and centrality evolution presented. The results indicate strong interaction of the charm-quark or D0-meson with the medium.
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Papers by Yufu Lin