Blast-wave analysis of strange particlem_Tspectra in Pb–Pb collisions at the SPS

Abstract

Abstract. The transverse mass spectra of high statistics, high purity samples of K 0 S , Λ, Ξ and Ω particles produced in Pb-Pb collisions at SPS energy have been studied in the framework of the blast-wave model. The dependence of the freezeout parameters on particle species and event centrality is discussed. Results at 40 A GeV/c are presented here for the first time.

Indication of transverse radial flow in high-multiplicity proton–proton collisions at the Large Hadron Collider

“…At SPS, the blast-wave analysis [36] of transverse mass spectra of pions, kaons and protons from 200 A GeV sulfur-sulfur (SS) and 158 A GeV lead-lead (PbPb) collisions data of fixed-target experiments provided evidence of collective transverse flow from the heavy-ioninduced central collisions. Interestingly, however, the analysis [37] of the transverse mass spectra of strange particles in PbPb collisions at 40 and 158 A GeV/c blast-wave fits to single and multiple strange particles separately. In fact, experimental observations at SPS heavy-ion collisions indicate to the scenario where multi-strange hadrons are formed and get decoupled from the system earlier, at large energy-density, than the common freeze-out of other hadrons [38].…”

Results from NA57

“…Transverse mass spectra obtained for K 0 S and for Λ, Ξ − , Ω − and their antiparticles for the two beam momenta are shown in the leftmost two panels of figure 1 [6,7] § The m T spectra have been analyzed within the blast wave model [8] assuming a linear velocity profile. The blast wave fits are shown as dotted lines in figure 1.…”

Latest results from NA57

“…The expansion dynamics of the Pb-Pb collisions has been studied in the transverse and longitudinal directions by measuring, respectively, the m¤ ( [5,6]) and the rapidity distributions (details in ref. [7]) of strange particles, based on a hydro-dynamics inspired model [8].…”