Central-to-peripheral nuclear modification factors in Pb-Pb collisions at $\sqrt{s_{NN}}$= 17.3 GeV

We present central-to-peripheral nuclear modification factors, $R_{CP}$, for the $p_{T}$ distributions of $K_{S}^{0}$, $\Lambda$, $\bar{\Lambda}$, and negatively charged particles, measured at central rapidity in Pb-Pb collisions at top SPS energy. The data cover the 55% most central fraction of the inelastic cross section. The $K_{S}^{0}$ and $\Lambda$ $R_{CP}$ $p_{T}$ are similar in shape to those measured at $\sqrt{s_{NN}}$ = 200 GeV at RHIC, though they are larger in absolute value. We have compared our $K_{S}^{0}$ $R_{CP}$ data to a theoretical calculation. The prediction overestimates the data at $p_{T}$ $\approx$ 3-4 GeV/$c$, unless sizeable parton energy loss is included in the calculation. We present central-to-peripheral nuclear modification factors, R_CP, for the p_T distributions of K^0_S, Lambda, Anti-Lambda, and negatively charged particles, measured at central rapidity in Pb-Pb collisions at top SPS energy. The data cover the 55% most central fraction of the inelastic cross section. The K^0_S and Lambda R_CP(p_T) are similar in shape to those measured at sqrt{s_NN} = 200 GeV at RHIC, though they are larger in absolute value. We have compared our K^0_S R_CP data to a theoretical calculation. The prediction overestimates the data at p_T \approx 3-4 GeV/c, unless sizeable parton energy loss is included in the calculation. We present central-to-peripheral nuclear modification factors, RCP , for the pT distributions of KS0 , Λ, Λ¯ , and negatively charged particles, measured at central rapidity in Pb–Pb collisions at top SPS energy. The data cover the 55% most central fraction of the inelastic cross section. The KS0 and Λ RCP(pT) are similar in shape to those measured at sNN=200 GeV at RHIC, though they are larger in absolute value. We have compared our KS0 RCP data to a theoretical calculation. The prediction overestimates the data at pT≈3–4 GeV/c , unless sizeable parton energy loss is included in the calculation.