Nuclear dependence of light neutral meson production in p-A collisions at 400GeV with NA60

The NA60 experiment has studied low-mass muon pair production in proton-nucleus collisions with a system of Be, Cu, In, W, Pb andU targets, using a 400GeV proton beam at the CERN SPS. The transverse momentum spectra of the / and phi mesons are measured in the full pT range accessible, from pT=0 up to 2. The cross section ratios sigma/sigma, sigma/sigma and sigma phi/sigma have been studied as a function of the sizeA of the production target, and an increase of the and phi yields relative to the is observed from p-Be to p-U collisions.