Strange pentaquark hadrons in statistical hadronization

We study, within the statistical hadronization model, the influence of narrow strangeness carrying baryon resonances (pentaquarks) on the understanding of particle production in relativistic heavy ion collisions. There is a great variation of expected yields as a function of heavy ion collision energy due to rapidly evolving chemical conditions at particle chemical freeze-out. At relatively low collision energies, these new states lead to improvement of statistical hadronization fits.

Figure 1

(Color online) ${\chi }^2$∕dof for statistical hadronization fits at the CERN SPS and RHIC: results are shown for $40A$,$80A$, $158A\text{GeV}\text{Pb}$ on stationary Pb target collisions and at RHIC for $65+65A$ and $100+100A\text{GeV}\text{Au}\text{−}\text{Au}$ head on interactions.

Figure 2

(Color online) Yield of ${\Theta }^{+}\left(1540\right)$ in relativistic heavy ion collisions, based on statistical hadronization fit to hadronization parameters at the CERN SPS and RHIC $40A$,$80A$,$158A\text{GeV}\text{Pb}$ on stationary Pb target collisions and at RHIC for $65+65A$ and $100+100A\text{GeV}\text{Au}\text{−}\text{Au}$ head on interactions. Relative yields with $K_s,\Lambda ,$ and $\Lambda \left(1520\right)$ are shown from bottom to top.

Figure 3

(Color online) Relative yields ${\Xi }^{--}\left(1862\right)∕{\Xi }^{-}$ and ${\Sigma }^{-}\left(1786\right)∕\Lambda$ are shown from bottom to top, see Fig. 2 for further details.