Pion and kaon production in centralPb+Pbcollisions at20Aand30AGeV: Evidence for the onset of deconfinement

C Alt,G I Veres,P Bunčić,P Christakoglou,Z Fodor,S Kniege,C Roland,P Chung,J G Cramer,J Sziklai,M Botje,R Lacey,K Grebieszkow,C Strabel,D Panayotov,C Höhne,A Sandoval,K Kadija,A Petridis,J Zimányi,G L Melkumov,G Vesztergombi,D Varga,G Stefanek,M Kreps,F Siklér,V Eckardt,E Skrzypczak,V Friese,A Karev,B Baatar,M Kowalski,D Flierl,M Szuba,P Foka,M Rybczyński,C Blume,M Makariev,H Białkowska,B Boimska,D Barna,F Pühlhofer,J Bartke,J Pluta,D Prindle,V Nicolic,M Gaździcki,M Van Leeuwen,S Hegyi,H Ströbele,G Roland,I Kraus,M Vassiliou,T Kollegger,A Mischke,P Dinkelaker,A Wetzler,B Lungwitz,W Peryt,R Renfordt,M Kliemant,M Mitrovski,A Rybicki,J Molnár,Z Włodarczyk,T Schuster,E Gładysz,M Pikna,P Lévai,V Genchev,D Vranić,L Betev,G Pálla,R Stock,R Bramm,P Csató,N Schmitz,P Seyboth,I Szentpétery,V Trubnikov,L Litov,M Mateev,János Gál ,A Malakhov ,B Sitár ,T Šuša ,E Kornaś ,J Braciník ,D P Kikoła ,P Szymański ,A Panagiotou ,S Mrówczyński ,T Antičić ,I.-K Yoo ,M Słodkowski ,V Kolesnikov ,V Černý ,O Chvála ,Á László

doi:10.1103/physrevc.77.024903

Abstract

Results on charged pion and kaon production in central Pb+Pb collisions at 20A and 30A GeV are presented and compared to data at lower and higher energies. A rapid change of the energy dependence is observed around 30A GeV for the yields of pions and kaons as well as for the shape of the transverse mass spectra. The change is compatible with the prediction that the threshold for production of a state of deconfined matter at the early stage of the collisions is located at low SPS energies.

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