Energy dependence of pion and kaon production in central Pb + Pb collisions.

The NA49 collaboration Afanasiev, S.V. ; Anticic, T. ; Barna, D. ; et al.
Phys.Rev.C 66 (2002) 054902, 2002.
Inspire Record 586383 DOI 10.17182/hepdata.31729

Measurements of charged pion and kaon production in central Pb+Pb collisions at 40, 80 and 158 AGeV are presented. These are compared with data at lower and higher energies as well as with results from p+p interactions. The mean pion multiplicity per wounded nucleon increases approximately linearly with s_NN^1/4 with a change of slope starting in the region 15-40 AGeV. The change from pion suppression with respect to p+p interactions, as observed at low collision energies, to pion enhancement at high energies occurs at about 40 AGeV. A non-monotonic energy dependence of the ratio of K^+ to pi^+ yields is observed, with a maximum close to 40 AGeV and an indication of a nearly constant value at higher energies.The measured dependences may be related to an increase of the entropy production and a decrease of the strangeness to entropy ratio in central Pb+Pb collisions in the low SPS energy range, which is consistent with the hypothesis that a transient state of deconfined matter is created above these energies. Other interpretations of the data are also discussed.

33 data tables

The centrality of the collisions expressed as a percentage of the inelastic cross section (7.15nb), and the mean numbers of wounded nuclei.

The inverse slope parameter of the fitted transverse mass spectra.

The rapidity density averaged over the rapidity interval -0.6 to 0.6.

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Anti-proton production in 14.6-A/GeV/c Si + A collisions

The E-802 collaboration Abbott, T. ; Akiba, Y. ; Beavis, D. ; et al.
Phys.Lett.B 271 (1991) 447-452, 1991.
Inspire Record 318378 DOI 10.17182/hepdata.29302

Antiproton production cross sections have been measured for minimum bias and central Si+Al and Si+Au collisions at 14.6 A GeV c . The data presented cover the range of transverse momentum from 0.3 to 1.2 GeV c and lab rapidities from 1.1 to 1.7 units. The relative p π − and p K − yields are found to be the smallest for the heaviest system measured, central Si+Au collisions. For these collisions, the p π − ratio, determined from integrated yields for 1.1⩽ y ⩽1.7, is (0.84±0.07)×10 −3 . In the same rapidity interval, the average antiproton inverse m ⊥ slope is 141±14 MeV for central Si+Al and central Si+Au collisions.

2 data tables

Definition of the CENTRAL and MINIMUM BIAS events see text.

Definition of the CENTRAL and MINIMUM BIAS events see text.