Search results for "Relativistic heavy ion"
showing 10 items of 66 documents
"Figure 11" of "Cold-nuclear-matter effcts on heavy-quark production in d+Au collisions at sqrt(s_NN)=200 GeV"
2023
Heavy flavor electron $R_{dA}$ 60-88% $d$+Au collisions. The nuclear modification factor, $R_{dA}$, for electrons from open heavy flavor decays, for the (a) most central and (b) most peripheral centrality bins.
"Figure 8" of "Cold-nuclear-matter effcts on heavy-quark production in d+Au collisions at sqrt(s_NN)=200 GeV"
2023
Heavy flavor electron RdA 0-20% $d$+Au collisions. The nuclear modification factor, $R_{dA}$, for electrons from open heavy flavor decays, for the (a) most central and (b) most peripheral centrality bins.
"Figure 9" of "Cold-nuclear-matter effcts on heavy-quark production in d+Au collisions at sqrt(s_NN)=200 GeV"
2023
Heavy flavor electron $R_{dA}$ 20-40% $d$+Au collisions. The nuclear modification factor, $R_{dA}$, for electrons from open heavy flavor decays, for the (a) most central and (b) most peripheral centrality bins.
"Figure 7" of "Cold-nuclear-matter effcts on heavy-quark production in d+Au collisions at sqrt(s_NN)=200 GeV"
2023
Heavy flavor electron $R_{dA}$ 0-100% d+Au collisions. The nuclear modification factors $R_{dA}$ and $R_{AA}$ for minimum bias $d$+Au and Au+Au collisions, for the $\pi^{0}$ and $e^{\pm}_{HF}$. The two boxes on the right side of the plot represent the global uncertainties in the $d$+Au (left) and Au+Au (right) values of $N_{coll}$ . An additional common global scaling uncertainty of 9.7% on $R_{dA}$ and $R_{AA}$ from the $p+p$ reference data is omitted for clarity.
"Figures 3-6" of "Cold-nuclear-matter effcts on heavy-quark production in d+Au collisions at sqrt(s_NN)=200 GeV"
2023
Heavy flavor electron yield, $d$+Au $\implies$ CHARGED X. Electrons from heavy flavor decays, separated by centrality. The lines represent a fit to the previous $p+p$ result [23], scaled by $N_{coll}$. The inset shows the ratio of photonic background electrons determined by the converter and cocktail methods for Minimum Bias $d$+Au collisions, with error bars (boxes) that represent the statistical uncertainty on the converter data (systematic uncertainty on the photonic-electron cocktail).
"Figure 10" of "Cold-nuclear-matter effcts on heavy-quark production in d+Au collisions at sqrt(s_NN)=200 GeV"
2023
Heavy flavor electron $R_{dA}$ 40-60% $d$+Au collisions. The nuclear modification factor, $R_{dA}$, for electrons from open heavy flavor decays, for the (a) most central and (b) most peripheral centrality bins.
"Figures 1-2" of "Cold-nuclear-matter effcts on heavy-quark production in d+Au collisions at sqrt(s_NN)=200 GeV"
2023
Heavy flavor electron yield, Run-8 $p$ + $p$, $d$+Au collisions. Electrons from heavy flavor decays, separated by centrality. The lines represent a fit to the previous $p+p$ result [23], scaled by $N_{coll}$. The inset shows the ratio of photonic background electrons determined by the converter and cocktail methods for Minimum Bias $d$+Au collisions, with error bars (boxes) that represent the statistical uncertainty on the converter data (systematic uncertainty on the photonic-electron cocktail).
Measurement of spin-orbital angular momentum interactions in relativistic heavy-ion collisions
2020
The first evidence of spin alignment of vector mesons ($K^{*0}$ and $\phi$) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element $\rho_{00}$ is measured at midrapidity ($|y| <$ 0.5) in Pb-Pb collisions at a center-of-mass energy ($\sqrt{s_{\rm NN}}$) of 2.76 TeV with the ALICE detector. $\rho_{00}$ values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum ($p_{\rm T} <$ 2 GeV/$c$) for $K^{*0}$ and $\phi$ at a level of 3$\sigma$ and 2$\sigma$, respectively. No significant spin alignment is observed for the $K^0_S$ meson (spin = 0) in Pb-Pb collisions and for the vector mesons in $pp$ collisions. The meas…
A first estimate of $\eta/s$ in Au+Au reactions at E$_{\rm lab}=1.23$ $A$GeV
2020
The HADES experiment at GSI has recently provided data on the flow coefficients $v_1,...,v_4$ for protons in Au+Au reactions at $E_{\rm lab} = 1.23$~$A$GeV (or $\sqrt{s_\mathrm{NN}}=2.4$ GeV). This data allows to estimate the shear viscosity over entropy ratio, $\eta/s$ at low energies via a coarse graining analysis of the UrQMD transport simulations of the flow harmonics in comparison to the experimental data. By this we can provide for the first time an estimate of $\eta/s\approx0.65\pm0.15$ (or $(8\pm2)\,(4\pi)^{-1}$) at such low energies.
Influence of temperature-dependent shear viscosity on elliptic flow at backward and forward rapidities in ultrarelativistic heavy-ion collisions
2014
We explore the influence of a temperature-dependent shear viscosity over entropy density ratio $\eta/s$ on the azimuthal anisotropies v_2 and v_4 of hadrons at various rapidities. We find that in Au+Au collisions at full RHIC energy, $\sqrt{s_{NN}}=200$ GeV, the flow anisotropies are dominated by hadronic viscosity at all rapidities, whereas in Pb+Pb collisions at the LHC energy, $\sqrt{s_{NN}}=2760$ GeV, the flow coefficients are affected by the viscosity both in the plasma and hadronic phases at midrapidity, but the further away from midrapidity, the more dominant the hadronic viscosity is. We find that the centrality and rapidity dependence of the elliptic and quadrangular flows can help…