$R_{cp}$ as a function of $\eta$ for 1.5 < $p_T$ < 4.0 GeV/$c$ for different centrality classes. Systematic uncertainties which are point-to-point uncorrelated (sys-uncorr) and correlated (sys-corr) are shown.

RpA of charged hadrons as a function of pT at forward rapidity in p+Al various centrality bins.

RpA of charged hadrons as a function of pT at backward rapidity in p+Al various centrality bins.

RpA of charged hadrons as a function of eta at forward and backward rapidity in p+Al various centrality bins.

RpA of charged hadrons as a function of pT at forward rapidity in p+Au various centrality bins.

RpA of charged hadrons as a function of pT at backward rapidity in p+Au various centrality bins.

RpA of charged hadrons as a function of eta at forward and backward rapidity in p+Au various centrality bins.

RpA of charged hadrons as a function of Npart at forward and backward rapidity in p+Al collisions.

RpA of charged hadrons as a function of Npart at forward and backward rapidity in p+Au collisions.

Transverse momentum spectrum of $K^{*0} + \overline{K^{*0}}$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 13 TeV. The normalization uncertainty of $\pm2.6\%$ is excluded.

Transverse momentum spectrum of $\phi$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 13 TeV. The normalization uncertainty of $\pm2.6\%$ is excluded.

Transverse momentum spectrum of $p + \overline{p}$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 13 TeV. The normalization uncertainty of $\pm2.6\%$ is excluded.

Transverse momentum spectrum of $\Lambda + \overline{\Lambda}$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 13 TeV. The normalization uncertainty of $\pm2.6\%$ is excluded.

Transverse momentum spectrum of $\Xi^{-} + \overline{\Xi}^{+}$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 13 TeV. The normalization uncertainty of $\pm2.6\%$ is excluded.

Transverse momentum spectrum of $\Omega^{-} + \overline{\Omega}^{+}$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 13 TeV. The normalization uncertainty of $\pm2.6\%$ is excluded.

Transverse momentum spectrum of $K^{0}_{S}$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 7 TeV. The normalization uncertainty of $^{+7.3}_{-3.5}\%$ is excluded.

Transverse momentum spectrum of $\Lambda + \overline{\Lambda}$ measured at midrapidity ($|y|<0.5$) in inelastic pp collisions at $\sqrt{s}$ = 7 TeV. The normalization uncertainty of $^{+7.3}_{-3.5}\%$ is excluded.

Ratios of the transverse-momentum spectra of $\pi^{+} + \pi^{-}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $K^{+} + K^{-}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $K^{0}_{S}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $K^{*0} + \overline{K^{*0}}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $\phi$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $p + \overline{p}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $\Lambda + \overline{\Lambda}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $\Xi^{-} + \overline{\Xi}^{+}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

Ratios of the transverse-momentum spectra of $\Omega^{-} + \overline{\Omega}^{+}$ in inelastic pp collisions at $\sqrt{s}=13$ TeV to those for $\sqrt{s}={7}$ TeV. The normalization uncertainty of $^{+10.8}_{-6.3}\%$ is excluded.

$(K^{+} + K^{-})/(\pi^{+}+\pi^{-})$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$(K^{*0} + \overline{K^{*0}})/(\pi^{+}+\pi^{-})$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$K^{0}_{S}/(\pi^{+}+\pi^{-})$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$\phi/(\pi^{+}+\pi^{-})$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$\phi/(\pi^{+}+\pi^{-})$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 7 TeV.

Average transverse momentum of $\pi^{+}+\pi^{-}$ as a function of the center-of-mass energy.

Average transverse momentum of $K^{+} + K^{-}$ as a function of the center-of-mass energy.

Average transverse momentum of $K^{0}_{S}$ as a function of the center-of-mass energy.

Average transverse momentum of $K^{*0} + \overline{K^{*0}}$ as a function of the center-of-mass energy.

Average transverse momentum of $\phi$ as a function of the center-of-mass energy.

Average transverse momentum of $p + \overline{p}$ as a function of the center-of-mass energy.

Average transverse momentum of $\Lambda+\overline{\Lambda}$ as a function of the center-of-mass energy.

Average transverse momentum of $\Xi^{-} + \overline{\Xi}^{+}$ as a function of the center-of-mass energy.

Average transverse momentum of $\Omega^{-} + \overline{\Omega}^{+}$ as a function of the center-of-mass energy.

Ratio of $p_{\rm T}$-integrated yields of $K^{+} + K^{-}$ to $\pi^{+} + \pi^{-}$ as a function of the center-of-mass energy.

Ratio of $p_{\rm T}$-integrated yields of $p + \overline{p}$ to $\pi^{+} + \pi^{-}$ as a function of the center-of-mass energy.

Ratio of $p_{\rm T}$-integrated yields of $\Lambda+\overline{\Lambda}$ to $\pi^{+} + \pi^{-}$ as a function of the center-of-mass energy.

Ratio of $p_{\rm T}$-integrated yields of $\Xi^{-} + \overline{\Xi}^{+}$ to $\pi^{+} + \pi^{-}$ as a function of the center-of-mass energy.

Ratio of $p_{\rm T}$-integrated yields of $\Omega^{-} + \overline{\Omega}^{+}$ to $\pi^{+} + \pi^{-}$ as a function of the center-of-mass energy.

Ratio of $p_{\rm T}$-integrated yields of $\phi$ to $K^{+} + K^{-}$ as a function of the center-of-mass energy.

Ratio of $p_{\rm T}$-integrated yields of $K^{*0} + \overline{K^{*0}}$ to $K^{+} + K^{-}$ as a function of the center-of-mass energy.

$(p + \overline{p})$/($\pi^{+}+\pi^{-}$) particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$(\Lambda + \overline{\Lambda})/K^{0}_{S}$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$(\Omega^{-} + \overline{\Omega}^{+})/\phi$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$(\Xi^{-} + \overline{\Xi}^{+})/\phi$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 13 TeV.

$(\Omega^{-} + \overline{\Omega}^{+})/\phi$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 7 TeV.

$(\Xi^{-} + \overline{\Xi}^{+})/\phi$ particle ratio as a function of $p_{\rm T}$ measured in pp collisions at $\sqrt{s}$ = 7 TeV.

Invariant yield of negatively charged heavy-flavor muons as a function of $p_T$ in $d$+Au collisions for different centralities at (a) backward rapidity (Au-going) and (b) forward rapidity (d-going).

Invariant yield of negatively charged heavy-flavor muons as a function of $p_T$ in $d$+Au collisions for different centralities at (a) backward rapidity (Au-going) and (b) forward rapidity (d-going).

The nuclear modification factor $R_{dA}$, for negatively charged heavy-flavor muons in $d$+Au collisions.

The nuclear modification factor $R_{dA}$, for negatively charged heavy-flavor muons in $d$+Au collisions.

The nuclear modification factor $R_{dA}$, for negatively charged heavy-flavor muons in $d$+Au collisions.

The nuclear modification factor $R_{dA}$, for negatively charged heavy-flavor muons in $d$+Au collisions.

The nuclear modification factor $R_{dA}$, for negatively charged heavy-flavor muons in $d$+Au collisions.

Comparison of $R_{dA}$ as a function of $\langle N_{coll} \rangle$ for heavy-flavor leptons from different rapidity and $p_T$ bins.

Comparison of $R_{dA}$ as a function of $\langle N_{coll} \rangle$ for heavy-flavor leptons from different rapidity and $p_T$ bins.

Heavy flavor muon double differential cross section in $p$+$p$ collisions at 1.4 < $|y|$ < 2.0.

$m^2$ (signal+background) distribution for $\bar{d}$,$d$ for $p_T$ = 1.6-2.9 GeV/$c$.

$m^2$ (background) distribution for $\bar{d}$,$d$ for $p_T$ = 1.6-2.9 GeV/$c$.

$m^2$ (signal) distribution for $\bar{d}$,$d$ for $p_T$ = 1.6-2.9 GeV/$c$.

Comparison of differential $v_2(p_T)$ for $\pi^{\pm}$. Results are shown for 20-60% central Au+Au collisions.

Comparison of differential $v_2(p_T)$ for $K^{\pm}$. Results are shown for 20-60% central Au+Au collisions.

Comparison of differential $v_2(p_T)$ for $(\bar{p})p$. Results are shown for 20-60% central Au+Au collisions.

Comparison of differential $v_2(p_T)$ for $\phi$ mesons. Results are shown for 20-60% central Au+Au collisions.

Comparison of differential $v_2(p_T)$ for $(\bar{d})d$. Results are shown for 20-60% central Au+Au collisions.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

$v_2$ vs $KE_T$ for several identified particle species obtained in mid-central Au+Au collisions, and ${v_2}/{n_q}$ vs ${KE_T}/{n_q}$ for the same particle species.

The $p_T$ spectra of electrons from the decays of open heavy flavor hadrons produced in Cu+Cu collisions, separated by centrality.

The $p_T$ spectra of electrons from the decays of open heavy flavor hadrons produced in Cu+Cu collisions, separated by centrality.

The $p_T$ spectra of electrons from the decays of open heavy flavor hadrons produced in Cu+Cu collisions, separated by centrality.

The nuclear modification factor for MB (0%–94%).

The nuclear modification factor for 0%–10%.

The nuclear modification factor for 0%–20%.

The nuclear modification factor for 20%–40%.

The nuclear modification factor for 40%–60%.

The nuclear modification factor for 60%–94%.

The nuclear modification factors for $e_{HF}$ at midrapidity in Cu+Cu collisions plotted as a function of $\langle N_{coll} \rangle$.

The nuclear modification factors for $e_{HF}$ at midrapidity in Cu+Cu collisions plotted as a function of $\langle N_{coll} \rangle$.

The nuclear modification factors for $e_{HF}$ at midrapidity in Cu+Cu collisions plotted as a function of $\langle N_{part} \rangle$.

The nuclear modification factors for $e_{HF}$ at midrapidity in Cu+Cu collisions plotted as a function of $\langle N_{part} \rangle$.

(Color online) (b) Integrated pion $R_{AA}$ over the range $5<p_{T}<8$ GeV/c versus $N_{part}$. The bands represent the systematic uncertainty on ratios. An additional scale error due to $pp$ normalization (∼14%) is not shown.

(Color online) (a) Nuclear modification factor, RAA, for protons and anti-protons ($p + \overline{p}$) in Cu+Cu (filled symbols) and Au+Au (open symbols) collisions at $\sqrt{s_{NN}}$=200 GeV. Error band is shown for most central Cu+Cu data to represent characteristic systematic uncertainties for Cu+Cu data. Error boxes at $R_{AA}$=1 represent Cu+Cu scale uncertainties due to the number of collisions and from pp spectra normalization.

(Color online) (a) Ratio of protons and anti-protons to charged pions, versus transverse momentum, for Cu+Cu collisions at $\sqrt{s_{NN}}$=200 GeV. For clarity, only one systematic error band is shown for Cu+Cu data (most central events), uncertainties on data in other centrality bins are similar in magnitude. Systematic errors for Au+Au data are not shown, for details see [9].

(Color online) (b) Average $(p+\overline{p})/(\pi^{+}+\pi^{-})$ ratio for $3<p_{T}<4$ GeV/c is shown as function of centrality ($N_{part}$) for Cu+Cu and Au+Au data. Error band represents the $pp$ measurement with uncertainty.

The ratios Anti-Λ/Λ, K+/K-, and Anti-Ξ+/Ξ- as a function of pT

Anti-baryon to baryon ratios measured by STAR

$J_{dA}$ plotted as a function of $\Delta\phi$.

Fig. 2. (Color online.) Event-by-event photon multiplicity distributions (solid circles) for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{s_{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV} .$ The distributions for top $0-5 \%$ central $\mathrm{Au}+$ Au collisions and top $0-10 \%$ central $\mathrm{Cu}+\mathrm{Cu}$ collisions are also shown (open circles). The photon multiplicity distributions for central collisions are observed to be Gaussian (solid line). Only statistical errors are shown. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 2. (Color online.) Event-by-event photon multiplicity distributions (solid circles) for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{s_{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV} .$ The distributions for top $0-5 \%$ central $\mathrm{Au}+$ Au collisions and top $0-10 \%$ central $\mathrm{Cu}+\mathrm{Cu}$ collisions are also shown (open circles). The photon multiplicity distributions for central collisions are observed to be Gaussian (solid line). Only statistical errors are shown. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 2. (Color online.) Event-by-event photon multiplicity distributions (solid circles) for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{s_{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV} .$ The distributions for top $0-5 \%$ central $\mathrm{Au}+$ Au collisions and top $0-10 \%$ central $\mathrm{Cu}+\mathrm{Cu}$ collisions are also shown (open circles). The photon multiplicity distributions for central collisions are observed to be Gaussian (solid line). Only statistical errors are shown. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 3. (Color online.) Photon pseudorapidity distributions for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{\mathrm{s}_{\mathrm{NN}}}=62.4$ and $200\mathrm{GeV}$. The results for several centrality classes are shown. The solid curves are results of HIJING simulations for central $(0-5 \%$ for $\mathrm{Au}+\mathrm{Au}$ and $0-10 \%$ for $\mathrm{Cu}+\mathrm{Cu})$ and $30-40 \%$ mid-central collisions. The errors shown are systematic, statistical errors are negligible in comparison. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 3. (Color online.) Photon pseudorapidity distributions for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{\mathrm{s}_{\mathrm{NN}}}=62.4$ and $200\mathrm{GeV}$. The results for several centrality classes are shown. The solid curves are results of HIJING simulations for central $(0-5 \%$ for $\mathrm{Au}+\mathrm{Au}$ and $0-10 \%$ for $\mathrm{Cu}+\mathrm{Cu})$ and $30-40 \%$ mid-central collisions. The errors shown are systematic, statistical errors are negligible in comparison. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 3. (Color online.) Photon pseudorapidity distributions for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{\mathrm{s}_{\mathrm{NN}}}=62.4$ and $200\mathrm{GeV}$. The results for several centrality classes are shown. The solid curves are results of HIJING simulations for central $(0-5 \%$ for $\mathrm{Au}+\mathrm{Au}$ and $0-10 \%$ for $\mathrm{Cu}+\mathrm{Cu})$ and $30-40 \%$ mid-central collisions. The errors shown are systematic, statistical errors are negligible in comparison. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 3. (Color online.) Photon pseudorapidity distributions for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{\mathrm{s}_{\mathrm{NN}}}=62.4$ and $200\mathrm{GeV}$. The results for several classes are shown. The solid curves are results of HIJING simulations for central $(0-5 \%$ for $\mathrm{Au}+\mathrm{Au}$ and $0-10 \%$ for $\mathrm{Cu}+\mathrm{Cu})$ and $30-40 \%$ mid-central collisions. The errors shown are systematic, statistical errors are negligible in comparison. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 4. (Color online.) Top panel: The number of photons divided by $\left\langle N_{\text{part}}\right\rangle / 2$ as a function of average number of participating nucleons for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{\mathrm{s} _{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV}$ for $-3.7<\eta<-2.3 .$ Errors shown are systematic only and include those for $\left\langle N_{\text {part }}\right\rangle .$ Results from HIJING are shown as lines (solid for $\mathrm{Au}+\mathrm{Au}$ and dashed for $\mathrm{Cu}+\mathrm{Cu}$ ). Bottom panel: Same as above, for both photons and charged particles from PHOBOS [10]. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 4. (Color online.) Top panel: The number of photons divided by $\left\langle N_{\text{part}}\right\rangle / 2$ as a function of average number of participating nucleons for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{\mathrm{s} _{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV}$ for $-3.7<\eta<-2.3 .$ Errors shown are systematic only and include those for $\left\langle N_{\text {part }}\right\rangle .$ Results from HIJING are shown as lines (solid for $\mathrm{Au}+\mathrm{Au}$ and dashed for $\mathrm{Cu}+\mathrm{Cu}$ ). Bottom panel: Same as above, for both photons and charged particles from PHOBOS [10]. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.

Fig. 5. (Color online.) Photon pseudorapidity distributions normalized by the average number of participating nucleon pairs for different collision centralities are plotted as a function of pseudorapidity shifted by the beam rapidity (-5.36 for $200 \mathrm{GeV}$ and -4.19 for $62.4 \mathrm{GeV}$ ) for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ collisions at $\sqrt{s_{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV}$. Errors are systematic only, statistical errors are negligible in comparison. For clarity of presentation, results for only four centralities are shown. The $\mathrm{Cu}+$ Cu data are shifted by 0.1 unit in $\eta-y_{\text {beam }} .$ The solid line is a second order polynomial fit to the data (see text for details).

Fig. 5. (Color online.) Photon pseudorapidity distributions normalized by the average number of participating nucleon pairs for different collision centralities are plotted as a function of pseudorapidity shifted by the beam rapidity (-5.36 for $200 \mathrm{GeV}$ and -4.19 for $62.4 \mathrm{GeV}$ ) for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ collisions at $\sqrt{s_{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV}$. Errors are systematic only, statistical errors are negligible in comparison. For clarity of presentation, results for only four centralities are shown. The $\mathrm{Cu}+$ Cu data are shifted by 0.1 unit in $\eta-y_{\text {beam }} .$ The solid line is a second order polynomial fit to the data (see text for details).