Nuclear modification at ?{sNN }\sqrt {s_{NN} } = 17.3 GeV, measured at NA49

Transverse momentum spectra up to 4.5GeV/c were measured around midrapidity in Pb+Pb reactions at ?{s_NN }\sqrt {s_{NN} } = 17.3GeV, for π ^±, p, `(p)]\bar p and K ^±, by the NA49 experiment. The nuclear modification factors R _AA , R _AA/pA and R _CP were extracted and are compared to RHIC results at ?{S_NN }\sqrt {S_{NN} } = 200GeV. The modification factor R _AA shows a rapid increase with transverse momentum in the covered region. The modification factor R _CP shows saturation well below unity in the π ^± channel. The extracted R _CP values follow the 200GeV RHIC results closely in the available transverse momentum range for all particle species. For π ^± above 2.5GeV/c transverse momentum, the measured suppression is smaller than that observed at RHIC. The nuclear modification factor R _AA/pA for π ^± stays well below unity.