Jet structure of baryon excess in Au+Au collisions at $\sqrt{s_{\mathit{NN}}}=200\mathrm{GeV}$

Two particle correlations between identified meson and baryon trigger particles with $2.5<p_T<4.0\mathrm{GeV}/c$ and lower $p_T$ charged hadrons have been measured at midrapidity by the PHENIX experiment at RHIC in $p+p,d+\mathrm{Au}$, and $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=200\mathrm{GeV}$. In noncentral $\mathrm{Au}+\mathrm{Au}$ collisions, the probability of finding a hadron near in azimuthal angle to the trigger particles is almost identical for mesons and baryons and significantly higher than in $p+p$ collisions. The associated yields for trigger baryons decrease in the most central collisions, consistent with some baryon production by thermal recombination in addition to hard scattering.

Figure 1

(Color online) Top panels show $\Delta \varphi$ distributions for meson (left) and baryon (right) triggers with $2.5<p_T<4.0\mathrm{GeV}/c$ and associated charged hadrons with $1.7<p_T<2.5\mathrm{GeV}/c$ in $\mathrm{Au}+\mathrm{Au}$ collisions. Bottom panels show the same quantity for meson triggers in $d+\mathrm{Au}$ collisions (left) and unidentified triggers in $p+p$ collisions (right). Lines indicate the calculated combinatorial background in the event modulated by the measured elliptic flow ($\mathrm{Au}+\mathrm{Au}$ only).

Figure 2

(Color online) Yield per trigger for associated charged hadrons between $1.7<p_T<2.5\mathrm{GeV}/c$ for the near- (top) and away- (bottom) side jets. The error bars are statistical errors, and the gray boxes are centrality-dependent systematic errors There is an additional 12% error on the overall normalization, which moves all points together. The dashed line (top) represents an upper limit of the centrality dependence of the near-side partner yield from thermal recombination (see text).

Figure 3

(Color online) $p_T$ spectra of the near-side associated charged hadrons corrected to the full jet yield for meson (left) and baryon (right) triggers at $2.5<p_T<4.0\mathrm{GeV}/c$ and $\left|\eta \right|<0.35$. Errors are statistical only. The curves are exponential fits.

Figure 4

(Color online) Inverse slopes from the fits in Fig. 3. Solid (open) squares and circles are $\mathrm{Au}+\mathrm{Au}$ ($d+\mathrm{Au}$), collisions and the triangle is $p+p$ collisons. The solid band indicates the slopes of inclusive particle spectra in $\mathrm{Au}+\mathrm{Au}$ collisions [11]. Errors are statistical only.