cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.17182/hepdata.150018.v1/t36
title: "Figure 14c-1" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: $v_2$ vs. $p_T$ for $\pi$/$K$/$p$ emitted from Au+Au at 62.4 and 200 GeV and Cu+Cu at 62.4 and 200 GeV for centralities given.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t37
title: "Figure 14c-2" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: $v_2$ vs. $p_T$ for $\pi$/$K$/$p$ emitted from Au+Au at 62.4 and 200 GeV and Cu+Cu at 62.4 and 200 GeV for centralities given.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t38
title: "Figure 14c-3" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: $v_2$ vs. $p_T$ for $\pi$/$K$/$p$ emitted from Au+Au at 62.4 and 200 GeV and Cu+Cu at 62.4 and 200 GeV for centralities given.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t39
title: "Figure 15a-1" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of $v_2$ between $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV for $\pi$/$K$/$p$ emitted from central Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t40
title: "Figure 15a-2" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of $v_2$ between $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV for $\pi$/$K$/$p$ emitted from central Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t41
title: "Figure 15a-3" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of $v_2$ between $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV for $\pi$/$K$/$p$ emitted from central Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t42
title: "Figure 15a-4" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of $v_2$ between $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV for $\pi$/$K$/$p$ emitted from central Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t43
title: "Figure 15b-1" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of $v_2$ between $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV for $\pi$/$K$/$p$ emitted from central Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t44
title: "Figure 15b-2" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of $v_2$ between $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV for $\pi$/$K$/$p$ emitted from central Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t45
title: "Figure 15b-3" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of $v_2$ between $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV for $\pi$/$K$/$p$ emitted from central Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t46
title: "Figure 16a-1" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of the $v_2$ of particles, antiparticles, for a minimum bias sample at 200 GeV and central 62.4 GeV Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t47
title: "Figure 16a-2" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of the $v_2$ of particles, antiparticles, for a minimum bias sample at 200 GeV and central 62.4 GeV Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t48
title: "Figure 16a-3" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of the $v_2$ of particles, antiparticles, for a minimum bias sample at 200 GeV and central 62.4 GeV Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.
DOI: 10.17182/hepdata.150018.v1/t49
title: "Figure 16b-1" of "Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV"

description: Comparison of the $v_2$ of particles, antiparticles, for a minimum bias sample at 200 GeV and central 62.4 GeV Au+Au collisions.
description: BNL-RHIC. We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{part}$. We observe that $v_2$ divided by eccentricity (ε) monotonically increases with $N_{part}$ and scales as $N^{1/3}_{part}$. The Cu+Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy ${KE}_T$ = $m_T$ − $m$ between 0.1 &lt; ${KE}_T$/$n_q$ &lt; 1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of $v_2$/($n_q$⋅ε⋅$N^{1/3}_{part}$) vs. ${KE}_T$/$n_q$ for all measured particles.