Search for critical fluctuations of the proton density in central A+A collisions at maximum SPS energy

Abstract

Abstract:We performed an intermittency analysis of the proton density fluctuations in transverse momentum space for the collisions Si+A (A=Al,Si,P) and C+A (A=C,N) at maximum SPS energy ( √ NN ≈ 17 GeV). In our analysis we used exclusively proton tracks in the midrapidity region (| C M | ≤ 0 75). For the Si+A system we find signature of power-law distributed density fluctuations quantified by the intermittency index φ 2 which approaches in size the predictions of critical QCD [Phys. Rev. Lett. 97, 032002 (2006)]. This result supports further the recent findings of power-law fluctuations in the density of (π + π − ) pairs with invariant mass close to their production threshold for the Si+Si at the same energy, reported in [Phys. Rev. C 81, 064907 (2010)

New results from fluctuation analysis in NA49 at the CERN SPS

“…Fluctuations of multiplicity and transverse momentum are maximal for Si + Si at the top SPS energy ( √ NN = 17 3 GeV). This, together with a maximal intermittent behavior of di-pions and protons [21,22], might be connected with the critical point. The results strongly motivate future experiments in the CERN SPS energy range.…”