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Energy dependence of kaon-to-proton ratio fluctuations in central Pb+Pb collisions from $\sqrt{s_{NN}}$ = 6.3 to 17.3~GeV

The NA49 collaboration Anticic, T. ; Baatar, B. ; Barna, D. ; et al.
Phys.Rev. C83 (2011) 061902, 2011.
Inspire Record 884686 DOI 10.17182/hepdata.58492

Kaons and protons carry large parts of two conserved quantities, strangeness and baryon number. It is argued that their correlation and thus also fluctuations are sensitive to conditions prevailing at the anticipated parton-hadron phase boundary. Fluctuations of the $(\mathrm{K}^+ + \mathrm{K}^-)/(\mathrm{p}+\bar{\mathrm{p}})$ and $\mathrm{K}^+/\mathrm{p}$ ratios have been measured for the first time by NA49 in central Pb+Pb collisions at 5 SPS energies between $\sqrt{s_{NN}}$= 6.3 GeV and 17.3 GeV. Both ratios exhibit a change of sign in $\sigma_{\mathrm{dyn}}$, a measure of non-statistical fluctuations, around $\sqrt{s_{NN}}$ = 8 GeV. Below this energy, $\sigma_{\mathrm{dyn}}$ is positive, indicating higher fluctuation compared to a mixed event background sample, while for higher energies, $\sigma_{\mathrm{dyn}}$ is negative, indicating correlated emission of kaons and protons. The results are compared to UrQMD calculations which which give a good description at the higher SPS energies, but fail to reproduce the transition to positive values.

2 data tables

The energy dependence of the event-by-event dynamical fluctuations of the (K+ + K-)/(P + PBAR) ratios.

The energy dependence of the event-by-event dynamical fluctuations of the (K+)/(P) ratios.


Energy dependence of phi meson production in central Pb+Pb collisions at s(NN)**(1/2) = 6 to 17 GeV

The NA49 collaboration Alt, C. ; Anticic, T. ; Baatar, B. ; et al.
Phys.Rev. C78 (2008) 044907, 2008.
Inspire Record 787913 DOI 10.17182/hepdata.25063

Phi meson production is studied by the NA49 collaboration in central Pb+Pb collisions at 20A, 30A, 40A, 80A and 158A GeV beam energy. The data are compared to measurements at lower and higher energies and to microscopic and thermal models. The energy dependence of yields and spectral distributions is compatible with the assumption that partonic degrees of freedom set in at low SPS energies.

20 data tables

PHI transverse momentum spectra at incident energy 20 GeV/nucleon integrated over the rapidity range 0 to 1.8.

PHI transverse momentum spectra at incident energy 30 GeV/nucleon integrated over the rapidity range 0 to 1.8.

PHI transverse momentum spectra at incident energy 40 GeV/nucleon integrated over the rapidity range 0 to 1.5.

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Pion and kaon production in central Pb + Pb collisions at 20-A and 30-A-GeV: Evidence for the onset of deconfinement

The NA49 collaboration Alt, C. ; Anticic, T. ; Baatar, B. ; et al.
Phys.Rev. C77 (2008) 024903, 2008.
Inspire Record 762554 DOI 10.17182/hepdata.25169

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.

13 data tables

Transverse mass spectra for pion production in the central rapidity region for collisions at 20 GeV per nucleon.

Transverse mass spectra for pion production in the central rapidity region for collisions at 30 GeV per nucleon.

Transverse mass spectra for kaon production in the central rapidity region for collisions at 20 GeV per nucleon.

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Inclusive production of charged pions in p+p collisions at 158-GeV/c beam momentum

The NA49 collaboration Alt, C. ; Anticic, T. ; Baatar, B. ; et al.
Eur.Phys.J. C45 (2006) 343-381, 2006.
Inspire Record 694016 DOI 10.17182/hepdata.43114

New results on the production of charged pions in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. Pions are identified by energy loss measurement in a large TPC tracking system which covers a major fraction of the production phase space. Inclusive invariant cross sections are given on a grid of nearly 300 bins per charge over intervals from 0 to 2 GeV/c in transverse momentum and from 0 to 0.85 in Feynman x. The results are compared to existing data in overlapping energy ranges.

26 data tables

Double differential cross sections for PI+ and PI- in P P interactions at 158 GeV.

Double differential cross sections for PI+ and PI- in P P interactions at 158 GeV.

Double differential cross sections for PI+ and PI- in P P interactions at 158 GeV.

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Two proton correlations from 158-A-GeV Pb + Pb central collisions

The NA49 collaboration Appelshauser, H. ; Bachler, J. ; Bailey, S.J. ; et al.
Phys.Lett. B467 (1999) 21-28, 1999.
Inspire Record 499383 DOI 10.17182/hepdata.31240

The two-proton correlation function at midrapidity from Pb+Pb central collisions at 158 AGeV has been measured by the NA49 experiment. The results are compared to model predictions from static thermal Gaussian proton source distributions and transport models RQMD and VENUS. An effective proton source size is determined by minimizing CHI-square/ndf between the correlation functions of the data and those calculated for the Gaussian sources, yielding 3.85 +-0.15(stat.) +0.60-0.25(syst.) fm. Both the RQMD and the VENUS model are consistent with the data within the error in the correlation peak region.

1 data table

The two proton correlation function was analysed using proton from the rapidity range YRAP = 2.4 to 2.9 in the TOF analysis, and 2.9 to 3.4 in the dE/dx analysis. Momentum magnitude of the proton in the rest frame of the pair. All quoted errors are statistical only. (C=CORRECTED) relates to correlation function corrected for 44% contamination in the proton pair sample due to weak decay protons. (C=UNCORRECTED) means uncorrected correlation function.


Event-by-event fluctuations of average transverse momentum in central Pb + Pb collisions at 158-GeV per nucleon

The NA49 collaboration Appelshauser, H. ; Bachler, J. ; Bailey, S.J. ; et al.
Phys.Lett. B459 (1999) 679-686, 1999.
Inspire Record 498247 DOI 10.17182/hepdata.41648

We present first data on event-by-event fluctuations in the average transverse momentum of charged particles produced in Pb+Pb collisions at the CERN SPS. This measurement provides previously unavailable information allowing sensitive tests of microscopic and thermodynamic collision models and to search for fluctuations expected to occur in the vicinity of the predicted QCD phase transition. We find that the observed variance of the event-by-event average transverse momentum is consistent with independent particle production modified by the known two-particle correlations due to quantum statistics and final state interactions and folded with the resolution of the NA49 apparatus. For two specific models of non-statistical fluctuations in transverse momentum limits are derived in terms of fluctuation amplitude. We show that a significant part of the parameter space for a model of isospin fluctuations predicted as a consequence of chiral symmetry restoration in a non-equilibrium scenario is excluded by our measurement.

1 data table

Studied YRAP (for PI's) is in a region of 4 TO 5.5.


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. C66 (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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Production of Phi mesons in p + p, p + Pb and central Pb + Pb collisions at E(beam) = 158-A-GeV

The NA49 collaboration Afanasev, S.V. ; Anticic, T. ; Bachler, J. ; et al.
Phys.Lett. B491 (2000) 59-66, 2000.
Inspire Record 537897 DOI 10.17182/hepdata.27038
7 data tables

Transverse mass distribution for PHI mesons produced in PB PB collisions averaged over the rapidity region 3.0 to 3.8.

Transverse mass distribution for PHI mesons produced in P P collisions averaged over the rapidity region 2.9 to 4.5.

Rapidity distributions for PHI mesons produced in PB PB collisions.

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Xi and anti-xi production in 158-GeV / nucleon Pb + Pb collisions

The NA49 collaboration Appelshauser, H. ; Bachler, J. ; Bailey, S.J. ; et al.
Phys.Lett. B444 (1998) 523-530, 1998.
Inspire Record 477539 DOI 10.17182/hepdata.31330

We report measurements of Xi and Xi-bar hyperon absolute yields as a function of rapidity in 158 GeV/c Pb+Pb collisions. At midrapidity, dN/dy = 2.29 +/- 0.12 for Xi, and 0.52 +/- 0.05 for Xi-bar, leading to the ratio of Xi-bar/Xi = 0.23 +/- 0.03. Inverse slope parameters fitted to the measured transverse mass spectra are of the order of 300 MeV near mid-rapidity. The estimated total yield of Xi particles in Pb+Pb central interactions amounts to 7.4 +/- 1.0 per collision. Comparison to Xi production in properly scaled p+p reactions at the same energy reveals a dramatic enhancement (about one order of magnitude) of Xi production in Pb+Pb central collisions over elementary hadron interactions.

2 data tables

Data are given at the midrapidity value.

Requested data from authors.


Phi emission in central Pb + Pb collisions at 158-GeV/u

The NA49 collaboration Appelshauser, H. ; Bachler, J. ; Bailey, S.J. ; et al.
Nucl.Phys. A638 (1998) 431-434, 1998.
Inspire Record 481889 DOI 10.17182/hepdata.36218
2 data tables

5% most central collosions, MT - M0 = 0 - 1.4 GeV, preliminary data.

5% most central events.


Hadron yields and hadron spectra from the NA49 experiment

The NA49 collaboration Jones, P.G. ; Afanasev, S.V. ; Alber, T. ; et al.
Nucl.Phys. A610 (1996) 188C-199C, 1996.
Inspire Record 432742 DOI 10.17182/hepdata.36468
4 data tables

CENTRAL COLLISIONS, PRELIMINARY DATA.

CENTRAL COLLISIONS, PRELIMINARY DATA.

CENTRAL COLLISIONS, PRELIMINARY DATA.

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