Identified Particle Distributions in $pp$ and $\mathrm{Au}+\mathrm{Au}$ Collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$

Transverse mass and rapidity distributions for charged pions, charged kaons, protons, and antiprotons are reported for $\sqrt{s_{NN}}=200\mathrm{GeV}$ $pp$ and $\mathrm{Au}+\mathrm{Au}$ collisions at Relativistic Heary Ion Collider (RHIC). Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and long duration from chemical to kinetic freeze-out in central $\mathrm{Au}+\mathrm{Au}$ collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.

Figure 1

Invariant yield as functions of transverse mass for ${\pi }^{\pm }$, $K^{\pm }$, and inclusive $p$ and $\overline{p}$ at midrapidity ($|y|<0.1$) for $pp$ (bottom) and $\mathrm{Au}+\mathrm{Au}$ events from (70–80)% (second from bottom) to the (0–5)% centrality bin (top). The curves shown are explained in the text.

Figure 2

Rapidity distributions of the fiducial yields and integrated $⟨p_{\perp }⟩$.

Figure 3

(a) $⟨p_{\perp }⟩$ and (b) $K^{-}/{\pi }^{-}$ and $\overline{p}/{\pi }^{-}$ as a function of $d{N}_{\mathrm{ch}}/d\eta$. (c) Midrapidity $K^{-}/\pi$ as a function of $\frac{(dN/dy{)}_{\pi }}{S}$. Systematic errors are shown for STAR data, and statistical errors for other data.

Figure 4

(a) $\sqrt{(dN/dy{)}_{\pi }/S}$ (stars), $T_{\mathrm{ch}}$ (circles), and $T_{\mathrm{kin}}$ (triangles), and (b) $⟨\beta ⟩$ as a function of $d{N}_{\mathrm{ch}}/d\eta$. Errors are systematic.