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Production in Pb + Pb and p + p collisions at 30, 40 and 158 A·GeV

Production in Pb + Pb and p + p collisions at 30, 40 and 158 A·GeV. Michael Mitrovski for the NA49 Collaboration. W discovery (1964). W at NA49 (2003). SQM - Atlantic Beach - March 2003. — 40 A·GeV Pb + Pb. — 30 A·GeV Pb + Pb. — 158 GeV p + p. Outline. Motivation.

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Production in Pb + Pb and p + p collisions at 30, 40 and 158 A·GeV

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  1. Production in Pb + Pb and p + p collisions at 30, 40 and 158 A·GeV Michael Mitrovski for the NA49 Collaboration W discovery (1964) Wat NA49 (2003) SQM - Atlantic Beach - March 2003

  2. — 40 A·GeV Pb + Pb — 30 A·GeV Pb + Pb —158 GeV p + p Outline • Motivation • The NA49 experiment •  reconstruction in the NA49 TPC • Yields and Spectra : • —158 A·GeV Pb + Pb • + / - : • Summary • Outlook Michael Mitrovski SQM - Atlantic Beach - March 2003 2/17

  3. Motivation • A sharp maximum in energy • dependence of relative • strangeness yield at low • SPS energies. • What is the energy dependence • of multistrange hyperons, • in particluar - and + ? Michael Mitrovski SQM - Atlantic Beach - March 2003 3/17

  4. TOF-GL Vertex Magnets MTPC-L TOF-TL VTX-1 VTX-2 BPD-1 Beam VTPC-2 VTPC-1 S1 RCAL COLL VCAL TOF-TR MTPC-R TOF-GR BPD-2 BPD-3 T S2‘ S3 V0 The NA49 experiment Michael Mitrovski SQM - Atlantic Beach - March 2003 4/17

  5. p Cuts to reduce Background :   • Charged particle selections. • (dE/dx identification for p and K). •  selection cuts. • selection cuts.  + p   K   + K   Vertex  Reconstruction •  + K br = 67.8 %    + p br = 63.9 %  (sss) m =1.67245 GeV/c2, c = 2.46 cm Michael Mitrovski SQM - Atlantic Beach - March 2003 5/17

  6. + + = 0.45  0.05 (stat.) (mid-rapidity) = 0.383  0.081 (mid-rapidity) WA97 : - -  Invariant Mass Spectra Pb + Pb at 158 A·GeV (20 % most central, 3M events) Michael Mitrovski SQM - Atlantic Beach - March 2003 6/17

  7. Corrections Pb + Pb at 158 A·GeV • Branching ratios. • Geometrical acceptance. • Reconstruction Efficiency (embedding). Michael Mitrovski SQM - Atlantic Beach - March 2003 7/17

  8. 1 d2n t C e -m / T WA97 : T(- + +)= 251  19 MeV = mt dmtdy Transverse Mass Spectra Pb + Pb at 158 A·GeV - + Michael Mitrovski SQM - Atlantic Beach - March 2003 8/17

  9. Rapidity spectra -2 0 2 -2 0 2 + = 0.32  0.06 (stat.) (4-yield) - Pb + Pb at 158 A·GeV Michael Mitrovski SQM - Atlantic Beach - March 2003 9/17

  10. + + NA57: = 0.41  0.18 (stat.) (mid-rapidity) = 0.25  0.17 (mid-rapidity) - -  Invariant Mass Spectra Pb + Pb at 40 A·GeV (7 % most central, 579k events) NA49 PRELIMINARY Michael Mitrovski SQM - Atlantic Beach - March 2003 10/17

  11. Very first  signal at • 30 A·GeV. NA49 PRELIMINARY  Invariant Mass Spectra Pb + Pb at 30 A·GeV (7 % most central, 270k events) Michael Mitrovski SQM - Atlantic Beach - March 2003 11/17

  12. + = 0.67  0.62 (stat. + sys.) (mid-rapidity) -  Invariant Mass Spectra p + p at 158 GeV (minimum bias, 2.5M events) NA49 PRELIMINARY Michael Mitrovski SQM - Atlantic Beach - March 2003 12/17

  13. +/- Ratio NA49 PRELIMINARY • No significant energy dependence in central Pb + Pb at SPS. • The ratio at SPS is +/- 0.4. • No significant difference between Pb + Pb and p + p • interactions. Michael Mitrovski SQM - Atlantic Beach - March 2003 13/17

  14. B / B Ratio NA49 PRELIMINARY 4 6 8 10 12 14 16 18 20 • Energy dependence of B / B ratio gets weaker with increasing • strangeness content. Michael Mitrovski SQM - Atlantic Beach - March 2003 14/17

  15. Central Pb + Pb at 30 A·GeV : - First Signal at 30 A·GeV Summary • Central Pb + Pb at 158 A·GeV (fully corrected): • - similar inverse slopes for  - and +( T  280 MeV) • - Indication of broader rapidity distribution for  - ( = 1.0) than • + ( = 0.7) • - total yields <  -> = 0.47  0.07 and < + > = 0.15  0.02 • Uncorrected Ratios at midrapidity : Michael Mitrovski SQM - Atlantic Beach - March 2003 15/17

  16. Outlook • + / - - Ratio at 30 A·GeV. • -, + yields at 20 (?), 30 (?), 40 and 80 (?) A·GeVPb + Pb. • Analyze 2002 p + p data at 158 GeV. • (increase the statistics by a factor of 2) Michael Mitrovski SQM - Atlantic Beach - March 2003 16/17

  17. The NA49 collaboration C.Alt, T.Anticic, B.Baatar, D.Barna, J.Bartke, M.Behler, L.Betev, H.Bialkowska, A.Billmeier, C.Blume, B.Boimska, M.Botje, J.Bracinik, R.Bramm, R.Brun, P.Buncic, V.Cerny, O.Chvala, J.G.Cramer, P.Csató, P.Dinkelaker, V.Eckardt, P.Filip, H.G.Fischer, Z.Fodor, P.Foka, P.Freund, V.Friese, J.Gál, M.Gazdzicki, G.Georgopoulos, E.Gladysz, S.Hegyi, C.Höhne, K.Kadija, A.Karev, S.Kniege, V.I.Kolesnikov, T.Kollegger, R.Korus, M.Kowalski, I.Kraus, M.Kreps, M. van Leeuwen, P.Lévai, A.I.Malakhov, C.Markert, B.W.Mayes, G.L.Melkumov, C.Meurer, A.Mischke, M.Mitrovski, J.Molnár,St.Mrówczyński, G.Pálla, A.D.Panagiotou, K.Perl, A.Petridis, M.Pikna, L.Pinsky, F.Pühlhofer, J.G.Reid, R.Renfordt, W.Retyk, C.Roland, G.Roland, M. Rybczyński, A.Rybicki, A.Sandoval, H.Sann, N.Schmitz, P.Seyboth, F.Siklér, B.Sitar, E.Skrzypczak, G.Stefanek, R.Stock, H.Ströbele, T.Susa, I.Szentpétery, J.Sziklai, T.A.Trainor, D.Varga, M.Vassiliou, G.I.Veres, G.Vesztergombi, D.Vranić, S.Wenig, A.Wetzler, Z.Wlodarczyk, I.K.Yoo, J.Zaranek, J.Zimányi Michael Mitrovski SQM - Atlantic Beach - March 2003 17/17

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