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

discovery (1964)

Michael Mitrovski for the NA49 Collaboration

Zur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt.

SQM - Atlantic Beach - March 2003

at NA49 (2003)

OutlineZur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt.

Michael Mitrovski SQM - Atlantic Beach - March 2003 2/17

• reconstruction in the NA49 TPC

• Yields and Spectra :

—158 A·GeV Pb + Pb

• The NA49 experiment

• Summary

• Outlook

• Motivation

— 40 A·GeV Pb + Pb

— 30 A·GeV Pb + Pb —158 GeV p + p

• + / - :

MotivationZur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt.

Michael Mitrovski SQM - Atlantic Beach - March 2003 3/17

• 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 + ?

(GeV)NNs10 10

20

0.1

0.2

NA49AGSPHENIX


The NA49 experiment

Michael Mitrovski 4/17SQM - Atlantic Beach - March 2003

Beam

BPD-1

S1

VTX-1 VTX-2

Vertex Magnets MTPC-L

VTPC-1 VTPC-2

MTPC-R

RCAL COLL VCAL

TOF-TL

TOF-TR

TOF-GL

TOF-GR

13 m

V0 S3

BPD-2 BPD-3 T

S2‘

ReconstructionZur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt.

Michael Mitrovski 5/17

(sss) m = 1.67245 GeV/c2, c = 2.46 cm + K br = 67.8 % + p br = 63.9 %


p

p

+Zur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt.K

K

Zur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt. +

Cuts to reduce Background :

• Charged particle selections. (dE/dx identification for p and K).• selection cuts.• selection cuts.

Vertex


•

Invariant Mass SpectraZur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt.


Pb + Pb at 158 A·GeV (20 % most central, 3M events)


+

- = 0.45 0.05 (stat.) (mid-rapidity)

)2

) (GeV/c-,KL(m

1.6 1.65 1.7 1.75 1.80

20

40

60

80

100

120

140

160

180

200

220-W > 0.9 GeV/ctp

-1 < y < 1

)2

) (GeV/c+,KL(m

1.6 1.65 1.7 1.75 1.80

10

20

30

40

50

60

70

80

90 +W > 0.9 GeV/ctp

-1 < y < 1

WA97 : +

- = 0.383 0.081 (mid-rapidity)

CorrectionsZur Anzeige wird der QuickTime™ Dekompressor „TIFF (Unkomprimiert)“ benötigt.


Pb + Pb at 158 A·GeV


• Branching ratios.

• Geometrical acceptance.

• Reconstruction Efficiency (embedding).



Transverse Mass SpectraPb + Pb at 158 A·GeV

1

mt

d2n

dmtdy= C e -m / T

t

)2

(GeV/c0-mtm0 0.2 0.4 0.6 0.81 1.2 1.4

10-2

10-1

22 MeV±=270T

-

)2

(GeV/c0-mtm0 0.2 0.4 0.6 0.81 1.2 1.4

10-2

10-1

40 MeV±=290T

+

WA97 : T(- + +) = 251 19 MeV



Rapidity spectra


*y

0

0.2

0.07±=0.47Ò-

W·

0.2±=1.0s

20-2*y

0

0.1

0.02±=0.15Ò+

W·

0.1±=0.7s

20-2

+

- = 0.32 0.06 (stat.) (4-yield)



(7 % most central, 579k events)


+

- = 0.41 0.18 (stat.) (mid-rapidity)

)2

) (GeV/c-,KL(m1.6 1.65 1.7 1.75 1.80

5

10

15

20

25

30

35 -W>0.9 /GeV ctp

-0.5< <0.5y

)2

) (GeV/c+,KL(m1.6 1.65 1.7 1.75 1.80

2

4

6

8

10+W>0.9 /GeV ctp

-0.5< <0.5y

NA49 PRELIMINARY

NA57 : +

- = 0.25 0.17 (mid-rapidity)



(7 % most central, 270k events)


• Very first signal at 30 A·GeV.

)2

,K) (GeV/cL(m1.6 1.65 1.7 1.75 1.80

5

10

15

20

25

30

35

40

45

+W + -W > 0.9 GeV/ctp

-0.4 < y < 0.4

NA49 PRELIMINARY



(minimum bias, 2.5M events)

p + p at 158 GeV

+

- = 0.67 0.62 (stat. + sys.) (mid-rapidity)

)2

) (GeV/c-,KL(m1.64 1.66 1.68 1.7 1.72 1.74 1.76 1.78 1.80

5

10

15

20

25

30-W

-0.75< <0.75y

)2

) (GeV/c+,KL(m1.64 1.66 1.68 1.7 1.72 1.74 1.76 1.78 1.80

2

4

6

8

10

12

14 +W-0.75< <0.75y

NA49 PRELIMINARY



+/- Ratio

• 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.

10 1020

0.2

0.4

0.6

0.8

1

1.2

1.4Pb + Pb NA49

Pb + Pb NA57

Au + Au STAR preliminary

[GeV]NN s10 10

20

0.2

0.4

0.6

0.8

1

1.2

1.4Pb + Pb NA49

Pb + Pb NA57

Au + Au STAR preliminary

p + p NA49

p + p STAR preliminary

[GeV]NN sNA49 PRELIMINARY



• Energy dependence of B / B ratio gets weaker with increasing strangeness content.

B / B Ratio

10-3

10-2

10-1

1

-W/+W

L/L/p p

[ ]GeVNNs

-X/+X

4 6 8 10 12 14 16 18 20NA49 PRELIMINARY



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 :

• Central Pb + Pb at 30 A·GeV :

- First Signal at 30 A·GeV

central Pb + Pb p + p

40 A·GeV 158 GeV

0.41 0.18 0.67 0.62



Outlook

• + / - - Ratio at 30 A·GeV.

• -, + yields at 20 (?), 30 (?), 40 and 80 (?) A·GeV Pb + Pb.

• Analyze 2002 p + p data at 158 GeV. (increase the statistics by a factor of 2)



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

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

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