Pion multiplicity in nuclear collisions

Gazdzicki, M. ; Roehrich, D. ;
Z.Phys.C 65 (1995) 215-223, 1995.
Inspire Record 398172 DOI 10.17182/hepdata.14107

Data on the mean multiplicity ofπ- produced in minimum bias proton-proton, proton-neutron and proton-nucleus interactions as well as central nucleus-nucleus collisions at momenta of 1.4–400 GeV/c per nucleon have been compiled and studied. The results for neutron-neutron and nucleon-nucleon interactions were then constructed. The dependence of the mean pion multiplicity in proton-nucleus interactions and central collisions of identical nuclei are studied as a function of the collision energy and the nucleus mass number. The number of produced pions per participant nucleon in central collisions of identical nuclei is found to be independent of the number of participants at a fixed incident momentum per nucleon. The mean multiplicity of negatively charged hadrons per participant nucleon for central nucleus-nucleus collisions is lower by about 0.12 than the corresponding multiplicity for nucleon-nucleon interactions atpLAB≲15 A·GeV/c, whereas the result at 200 A·GeV/c is above the corresponding nucleon-nucleon multiplicity. This may indicate change of the collision dynamics at high energy.

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Charged particle multiplicities in nuclear collisions at 200-GeV/N

The NA35 collaboration Bächler, J. ; Bartke, J. ; Bialkowska, H. ; et al.
Z.Phys.C 51 (1991) 157-162, 1991.
Inspire Record 320907 DOI 10.17182/hepdata.14983

Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed.

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Strangeness enhancement in central S + S collisions at 200-GeV/nucleon.

The NA35 collaboration Baechler, J. ; Bartke, J. ; Bialkowska, H. ; et al.
Nucl.Phys.A 525 (1991) 221C-226C, 1991.
Inspire Record 328899 DOI 10.17182/hepdata.36820

None

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Charged Particle Multiplicities and Interaction Cross-sections in High-energy Nuclear Collisions

The NA35 collaboration Bamberger, A. ; Bangert, D. ; Bartke, J. ; et al.
Phys.Lett.B 205 (1988) 583-589, 1988.
Inspire Record 262284 DOI 10.17182/hepdata.42035

Inelastic cross sections at 60 and 200 GeV/nucleon are determined in a streamer chamber for 16 O on several nuclear targets. Charged particle multiplicity distributions for inelastic and central collisions are studied and compared with theoretical predictions. The inelastic cross section exhibit a geometrical dependence on nuclear radii. The multiplicity data are governed by the collision geometry. They are consistent with a picture of superposition of independent nucleon-nucleus interactions.

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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.

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Elliptic flow in Au + Au collisions at s(N N)**(1/2) = 130-GeV.

The STAR collaboration Ackermann, K.H. ; Adams, N. ; Adler, C. ; et al.
Phys.Rev.Lett. 86 (2001) 402-407, 2001.
Inspire Record 533414 DOI 10.17182/hepdata.93232

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt(s_NN)=130 GeV using the STAR TPC at RHIC. The elliptic flow signal, v_2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

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Neutral strange particle production in sulphur sulphur and proton sulphur collisions at 200-GeV/nucleon

The NA35 collaboration Bartke, J. ; Bialkowska, H. ; Bock, R. ; et al.
Z.Phys.C 48 (1990) 191-200, 1990.
Inspire Record 304994 DOI 10.17182/hepdata.15177

The production of Λ,\(\bar \Lambda\) andKs0 has been studied in 200 GeV/nucleonp+S and S+S collisions in the streamer chamber of the NA35 experiment at the CERN SPS. Significant enhancement of the multiplicities of all observed strange particles relative to negative hadrons was observed in central S+S collisions, as compared top+p andp+S collisions. The latter collisions show no overall (relative) strangeness enhancement overp+p, but the rapidity distributions and hadron multiplicities indicate some secondary cascading production of Λ particles in thep+S andp+Au collisions. The Λ polarization in central S+S collisions was found to be compatible with zero up topT=2 GeV/c.

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Production of charged kaons in central S + S and O + Au collisions at 200-GeV/nucleon

The NA35 collaboration Kowalski, M. ; Bachler, J. ; Bartke, J. ; et al.
Nucl.Phys.A 544 (1992) 609C-614C, 1992.
Inspire Record 343256 DOI 10.17182/hepdata.36667

Product of charged kaons in central S + S and O + Au collisions at 200 GeV/nucleon has been studied in the NA 35 Streamer Chamber experiment. Mean multiplicities and transverse mass distributions were obtained. They were compared with nucleon-nucleon data and with model predictions.

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Study of the Energy Flow in $^{16}$O Nucleus Collisions at 60-{GeV}/nucleon and 200-{GeV}/nucleon

The NA35 collaboration Heck, W. ; Bamberger, A. ; Bangert, D. ; et al.
Z.Phys.C 38 (1988) 19, 1988.
Inspire Record 262285 DOI 10.17182/hepdata.37151

We report a systematic study of mid-rapidityET production and forward energy flow in the interaction of16O projectiles on Al, Cu, Ag and Au at 60 and 200 GeV/nucleon. First results onET production with32S projectiles are presented.

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Energy dependence of phi meson production in central Pb+Pb collisions at $\sqrt{s}_{NN}$ = 6 to 17 GeV

The NA49 collaboration Alt, C. ; Anticic, T. ; Baatar, B. ; et al.
Phys.Rev.C 78 (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.

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