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.


Anti-proton production in relativistic Si nucleus collisions

The E814 collaboration Barrette, J. ; Bellwied, R. ; Braun-Munzinger, P. ; et al.
Phys.Rev.Lett. 70 (1993) 1763-1766, 1993.
Inspire Record 358657 DOI 10.17182/hepdata.19760

We have measured antiproton production cross sections as functions of centrality in collisions of 14.6 GeV/c per nucleon Si28 ions with targets of Al, Cu, and Pb. For all targets, the antiproton yields increase linearly with the number of projectile nucleons that have interacted, and show little target dependence. We discuss the implications of this result on the production and absorption of antiprotons within the nuclear medium.

5 data tables

No description provided.

No description provided.

No description provided.

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Antiproton production and antideuteron production limits in relativistic heavy ion collisions from BNL experiment 864.

The E864 collaboration Armstrong, T.A. ; Barish, K.N. ; Batsoulli, S. ; et al.
Phys.Rev.C 59 (1999) 2699-2712, 1999.
Inspire Record 478873 DOI 10.17182/hepdata.31371

We present results from Experiment 864 for antiproton production and antideuteron limits in Au + Pb collisions at 11.5 GeV/c per nucleon. We have measured invariant multiplicities for antiprotons for rapidities 1.4<y<2.4 at low transverse momentum as a function of collision geometry. When compared with the results from Experiment 878 our measurements suggest a significant contribution to the measured antiproton yield from the decay of strange antibaryons. We have also searched for antideuterons and see no statistically significant signal. Thus, we set upper limits on the production at approximately 3 x 10^{-7} per 10% highest multiplicity Au + Pb interaction.

7 data tables

CENTRALITY = 10 PCT.

CENTRALITY = 100 TO 70 PCT.

CENTRALITY = 70 TO 30 PCT.

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Strangelet search and light nucleus production in relativistic Si + Pt and Au + Pt collisions

The E886 collaboration Rusek, A. ; Bassalleck, B. ; Berdoz, A. ; et al.
Phys.Rev.C 54 (1996) R15-R19, 1996.
Inspire Record 429741 DOI 10.17182/hepdata.25801

A strangelet search in Si+Pt and Au+Pt collisions at alternating-gradient synchrotron (AGS) energies, using a focusing spectrometer, sensitive to mass per charge of 3-14 GeV/c2 was conducted during the 1992 and 1993 heavy ion runs at the AGS. The null results thereof are presented as upper limits on the invariant production cross section, in the range of 10−5-10−4 mb c3/GeV2, and model dependent sensitivity limits in the range of 10−7-10−5 per collision. Measurements of the production cross sections of several nonstrange nuclear systems, from p to Be7 and Li8, the background of the strangelet search, are also presented.

1 data table

No description provided.


Production of pi+-, K+-, p, and anti-p in relativistic Au + Pt, Si + Pt, and p + Pt collisions

The E886 collaboration Diebold, G.E. ; Bassalleck, B. ; Burger, T. ; et al.
Phys.Rev.C 48 (1993) 2984-2994, 1993.
Inspire Record 364483 DOI 10.17182/hepdata.26015

During the recent commissioning of Au beams at the Brookhaven Alternating Gradient Synchrotron facility, experiment 886 measured production cross sections for π±, K±, p, and p¯ in minimum bias Au+Pt collisions at 11.5A GeV/c. Invariant differential cross sections, Ed3σ/dp3, were measured at several rigidities (p/Z≤1.8 GeV/c) using a 5.7° (fixed-angle) focusing spectrometer. For comparison, particle production was measured in minimum bias Si+Pt collisions at 14.6A GeV/c using the same apparatus and in p+Pt collisions at 12.9 GeV/c using a similar spectrometer at KEK. When normalized to projectile mass, Aproj, the measured π± and K± cross sections are nearly equal for the p+Pt and Si+Pt reactions. In contrast to this behavior, the π− cross section measured in Au+Pt shows a significant excess beyond Aproj scaling of the p+Pt measurement. This enhancement suggests collective phenomena contribute significantly to π− production in the larger Au+Pt colliding system. For the Au+Pt reaction, the π+ and K+ yields also exceed Aproj scaling of p+Pt collisions. However, little significance can be attributed to these excesses due to larger experimental uncertainties for the positive rigidity Au beam measurements. For antiprotons, the Si+Pt and Au+Pt cross sections fall well below Aproj scaling of the p+Pt yields indicating a substantial fraction of the nuclear projectile is ineffective for p¯ production. Comparing with p+Pt multiplicities, the Si+Pt and Au+Pt antiproton yields agree with that expected solely from ‘‘first’’ nucleon-nucleon collisions (i.e., collisions between previously unstruck nucleons). In light of expected p¯ annihilation in the colliding system, such projectile independence is unexpected without additional (projectile dependent) sources of p¯ production. In this case, the data indicate an approximate balance exists between absorption and additional sources of antiprotons. This balance is remarkable given the wide range of projectile mass spanned by these measurements.

13 data tables

No description provided.

No description provided.

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Anti-baryon production in sulphur nucleus collisions at 200-GeV per nucleon

The NA35 collaboration Alber, T. ; Appelshäuser, H. ; Bächler, J. ; et al.
Phys.Lett.B 366 (1996) 56-62, 1996.
Inspire Record 427399 DOI 10.17182/hepdata.28428

Antiproton production near midrapidity has been studied in central collisions of 32 S with sulphur, silver and gold nuclei at 200 GeV per nucleon. The measured transverse mass distributions can be described by an exponential with inverse slope parameters of about 200 MeV, similar to those obtained from Λ spectra. The rapidity density increases weakly with the target mass, ranging from 0.4 to 0.7. The ratio Λ p near midrapidity is approximately 1.4 on average, significantly larger than the corresponding ratio observed in proton-proton and proton-nucleus collisions.

2 data tables

No description provided.

No description provided.


Kaon and proton ratios from central Pb + Pb collisions at the CERN SPS.

The NA44 collaboration Kaneta, M. ; Bearden, I.G. ; Bøggild, H. ; et al.
Nucl.Phys.A 638 (1998) 419-422, 1998.
Inspire Record 481886 DOI 10.17182/hepdata.36250

K − /K + and p ¯ / p ratios measured in 158 A·GeV Pb+Pb collisions are shown as a function of transverse momentum P T and centrality in top 8.5% central region. Little centrality dependence of the K − / K + and p ¯ / p ratios is observed. The transverse mass m T distribution and dN/dy of K + , K − , p and p ¯ around mid-rapidity are obtained. The temperature T ch and the chemical potentials for both light and strange quarks (μ q , μ s ) at chemical freeze-out are determined by applying simple thermodynamical model to the present data. The resultant μ q , μ s and T ch are compared with those obtained from similar analysis of SPS S+A and AGS Si+A data. The chemical freeze-out temperature T ch at CERN energies is higher than thermal freeze-out temperature T fo which is extracted from m T distribution of charged hadrons. At AGS energies T ch is close to T fo .

2 data tables

Data obtained from the fit of MT spectra.

Data obtained from the fit of MT spectra.


Charged hadron distributions in p A and A-A collisions at the CERN SPS

The NA44 collaboration Dodd, Jeremy ; Bøggild, H. ; Boissevain, J. ; et al.
Nucl.Phys.A 590 (1995) 523C-526C, 1995.
Inspire Record 407678 DOI 10.17182/hepdata.36504

Single particle distributions of π ± , K ± , p , p and d near mid-rapidity from 450 GeV/c p A and 200 GeV/c per nucleon SA collisions are presented. Inverse slope parameters are extracted from the transverse mass spectra, and examined for indications of collective phenomena. Proton and antiproton yields are determined for different projectile-target combinations. First results from 160 GeV/c per nucleon PbPb collisions are presented.

2 data tables

No description provided.

PRELIMINARY DATA FOR CENTRAL EVENTS.


Hadron distributions: Recent results from the CERN experiment NA44

The NA44 collaboration Xu, Nu ; Bearden, I.G. ; Bøggild, H. ; et al.
Nucl.Phys.A 610 (1996) 175C-187C, 1996.
Inspire Record 432743 DOI 10.17182/hepdata.36469

Proton distributions at midrapidity have been measured for 158A·GeV Pb+Pb collisions in the focusing spectrometer experiment NA44 at CERN. A high degree of nuclear stopping is found in the truly heavy ion collisions. Systematic results of single particle transverse momentum distributions of pions, kaons, and protons, of 200A·GeV S+S and 158A·GeV Pb+Pb central collisions will be addressed within the context of thermalization. By comparing these data with thermal and transport models, freeze-out parameters such as the temperature parameter T fo and mean collective flow velocity 〈β〉 are extracted. Preliminary results of the particle ratios of K − K + and p p are discussed in the context of cascade models of RQMD and VENUS.

1 data table

CENTRAL COLLISIONS: SIG(TRIG)/SIG(GEOM)=10%.


Collective expansion in high energy heavy ion collisions.

The NA44 collaboration Bearden, I.G. ; Boggild, H. ; Boissevain, J. ; et al.
Phys.Rev.Lett. 78 (1997) 2080-2083, 1997.
Inspire Record 426801 DOI 10.17182/hepdata.52345

Transverse mass spectra of pions, kaons, and protons from the symmetric heavy-ion collisions 200 A GeV S+S and 158 A GeV Pb+Pb, measured in the NA44 focusing spectrometer at CERN, are presented. The mass dependence of the slope parameters provides evidence of collective transverse flow from expansion of the system in heavy-ion induced central collisions.

3 data tables

(1/MT)*d(N)/d(MT) = A *exp(-MT/SLOPE).

(1/MT)*d(N)/d(MT) = A *exp(-MT/SLOPE).

The SLOPE from the parameterization of (1/MT)*d(N)/d(MT) = A*exp(-MT/SLOPE)is fitted as follows SLOPE = CONST(C=1) + M(hadron)*CONST(C=2)**2.