Date

Charmonia and Drell-Yan production in proton-nucleus collisions at the CERN SPS

The NA50 collaboration Alessandro, B ; Alexa, C ; Arnaldi, R ; et al.
Phys.Lett.B 553 (2003) 167-178, 2003.
Inspire Record 612573 DOI 10.17182/hepdata.29487

Charmonium production in p – A collisions is a unique tool for the study of the interaction of bound c c states in nuclear matter. It can provide details on the basic features of the resonance formation mechanism and, in particular, on its non-perturbative aspects. In this Letter, we present an experimental study of charmonia and Drell–Yan production in proton–nucleus collisions at 450 GeV/ c . The results are analyzed in the framework of the Glauber model and lead to the values of the nuclear absorption cross-section σ abs pA for J / ψ and ψ ′. Then, we compare the J / ψ absorption in proton–nucleus and sulphur–uranium interactions, using NA38 data. We obtain that, for the J / ψ , σ abs pA and σ abs SU are compatible, showing that no sizeable additional suppression mechanism is present in S–U collisions, and confirming that the anomalous J / ψ suppression only sets in for Pb–Pb interactions.

5 data tables match query

The J/PSI production cross section times the branching ratio to MU+ MU- pernucleon-nucleon collision for the differential nuclear targets.

The PSI(3685) production cross section times the branching ratio to MU+ MU-per nucleon-nucleon collision for the differential nuclear targets.

The Drell Yan cross section, divided by the mass number A, and multiplied by the isospin correction factors in the mass interval 2.9 to 4.5 GeV.

More…

Charmonium production and nuclear absorption in p A interactions at 450-GeV.

The NA50 collaboration Alessandro, B. ; Alexa, C. ; Arnaldi, R. ; et al.
Eur.Phys.J.C 33 (2004) 31-40, 2004.
Inspire Record 629957 DOI 10.17182/hepdata.30011

The production of ${\rm J}/\psi$ and

13 data tables match query

The J/PSI production cross sections, per target nucleon, times the di-muon branching ratio for the two data samples.

The PSI(3685) production cross sections, per target nucleon, times the di-muon branching ratio for the two data samples.

J/PSI production cross section times the di-muon branching ratio for the BEtarget as a function of the Feynman X bin.

More…

Anomalous J / psi suppression in Pb - Pb interactions at 158 GeV/c per nucleon

The NA50 collaboration Abreu, M.C. ; Alessandro, B. ; Alexa, C. ; et al.
Phys.Lett.B 410 (1997) 337-343, 1997.
Inspire Record 459314 DOI 10.17182/hepdata.28260

The Drell-Yan and J ψ cross-sections measured in PbPb collisions are compared with the values extrapolated from the results obtained in proton and light ion induced reactions. While the Drell-Yan production exhibits the normal expected behaviour, the yield of J ψ in PbPb interactions is abnormally low, as it lies 9 standard deviations below the expected value. Moreover, the departure from the expected behaviour increases significantly from peripheral to central collisions.

2 data tables match query

The results from other experiments are also presented.

Different data are rescaled at 200 GeV.


Charmonium production in Pb Pb interactions at 158-GeV/c per nucleon.

The NA50 collaboration Ramello, Luciano ; Abreu, M.C. ; Alessandro, B. ; et al.
Nucl.Phys.A 638 (1998) 261-278, 1998.
Inspire Record 481874 DOI 10.17182/hepdata.36232

The NA50 collaboration has measured J/ψ , ψ′ and Drell Yan pair production in Pb Pb interactions at 158 GeV/ c per nucleon at the CERN SPS. Final results from the 1995 run and preliminary ones from the higher statistics 1996 run are presented. A anomalous J/ψ suppression (relative to the Drell-Yan process) has been observed with respect to the suppression pattern established in experiments NA38 and NA51 with proton, oxygen and sulfur beams. The 1996 data allow a detailed study of the suppression pattern in the Pb Pb sample itself, showing a discontinuity around an E T value (the neutral transverse electromagnetic energy) of 50 GeV. The ψ′ is also suppressed relative to Drell-Yan, with a pattern very similar to the one observed in S U collisions. Finally, the p T distributions of dimuons are presented. The average p T 2 of the J/ψ in Pb Pb collisions does not increase any more with E T above 100 GeV.

1 data table match query

ET - neutral transverse energy in the electromagnetic calorimeter, etarap=1.1-2.3.


Search for multi - baryonic resonances in the anti-p + d ---> pi- + X reaction

Aslanides, E. ; Benabdelouahed, D. ; Bergdolt, A.M. ; et al.
Nucl.Phys.A 528 (1991) 608-620, 1991.
Inspire Record 323124 DOI 10.17182/hepdata.36714

The reaction p + d → π − + X has been studied at Saturne at 1.45, 2.10 and 2.70 GeV, using the spectrometer SPES III. The analysing power and the differential cross sections show no evidence for narrow structures which could be interpreted as a resonance in the three baryon system. At the lowest incident energy, the shapes of the experimental cross sections are well reproduced by phase-space distributions.

1 data table match query

Axis error includes +- 0.0/0.0 contribution (?////).


Anomalous J / psi suppression in Pb + Pb collisions at 158-A-GeV/c

The NA50 collaboration Gonin, Michel ; Abreu, M.C. ; Alexa, C. ; et al.
Nucl.Phys.A 610 (1996) 404C-417C, 1996.
Inspire Record 432728 DOI 10.17182/hepdata.36494

Cross sections for J ψ,ψ′ and Drell-Yan production in Pb+Pb collisions at 158×A GeV/c are presented and compared with results obtained by the NA38 and NA51 collaborations. The Pb+Pb data have been collected by the NA50 collaboration using the NA38 dimuon spectrometer. The Drell-Yan mechanism is found to scale as (A projectile · B target ) in p+B target and A projectile + B target collisions including Pb+Pb collisions. Regarding J ψ , an anomalous suppression is observed in Pb+Pb collisions with respect to the suppression observed in p+B target , O+B target and S+U collisions. The cross section ratios ψ′ ( J ψ ) are similar in Pb+Pb and S+U collisions.

2 data tables match query

No description provided.

No description provided.


Near-threshold production of omega mesons in the p p --> p p omega reaction.

Hibou, F. ; Bing, O. ; Boivin, M. ; et al.
Phys.Rev.Lett. 83 (1999) 492-495, 1999.
Inspire Record 496452 DOI 10.17182/hepdata.40430

The total cross section for omega production in the pp -> pp omega reaction has been measured at five c.m. excess energies from 3.8 to 30 MeV. The energy dependence is easily understood in terms of a strong proton-proton final state interaction combined with a smearing over the width of the state. The ratio of near-threshold phi and omega production is consistent with the predictions of a one-pion-exchange model and the degree of violation of the OZI rule is similar to that found in the pi-p -> n omega/phi reactions.

1 data table match query

Axis error includes +- 0.0/0.0 contribution (?////Not given separately).


eta-helium quasi-bound states.

Willis, N. ; Le Bornec, Y. ; Zghiche, A. ; et al.
Phys.Lett.B 406 (1997) 14-19, 1997.
Inspire Record 441131 DOI 10.17182/hepdata.40436

The cross section and tensor analysing power t_20 of the d\vec{d}->eta 4He reaction have been measured at six c.m. momenta, 10 < p(eta) < 90 MeV/c. The threshold value of t_20 is consistent with 1/\sqrt{2}, which follows from parity conservation and Bose symmetry. The much slower momentum variation observed for the reaction amplitude, as compared to that for the analogous pd->eta 3He case, suggests strongly the existence of a quasi-bound state in the eta-4He system and optical model fits indicate that this probably also the case for eta-3He.

1 data table match query

The spin-averaged amplitude squared is defined as follows: ABS(AMP)**2 = (P_deut/P_eta)*D(SIG)/D(OMEGA) and obtained by assuming the angular distributions to be isotropic. The errors in this quantity includes a contribution from Delta(P_eta). The statistical error of about 2% are added quadratically to the systemat ic error.


Evidence for narrow baryons in inelastic p p scattering.

Tatischeff, B. ; Willis, N. ; Comets, M.P. ; et al.
Phys.Rev.Lett. 79 (1997) 601-604, 1997.
Inspire Record 450173 DOI 10.17182/hepdata.19550

The reaction pp→pπ+N has been studied at three energies ( Tp=1520, 1805, and 2100 MeV) and six angles from 0° up to 17° (laboratory). Several narrow states have been observed in missing mass spectra at 1004, 1044, and 1094 MeV. Their widths are typically 1 order of magnitude smaller than the widths of N* or Δ. Possible biases are discussed. These masses are in good agreement with those calculated within a simple phenomenological mass formula based on color magnetic interaction between two colored quark clusters.

9 data tables match query

No description provided.

No description provided.

No description provided.

More…

J / psi and Drell-Yan cross-sections in Pb Pb interactions at 158 GeV/c per nucleon

The NA50 collaboration Abreu, M.C. ; Alessandro, B. ; Alexa, C. ; et al.
Phys.Lett.B 410 (1997) 327-336, 1997.
Inspire Record 459315 DOI 10.17182/hepdata.5631

First results are reported on J ψ and Drell-Yan cross-sections in PbPb reactions at 158 GeV/ c per nucleon. The ratio of cross-sections σ J/ψ /σ DY is studied as a function of the impact parameter of the collision estimated from the measured transverse energy.

5 data tables match query

No description provided.

No description provided.

The Drell-Yan cross sections are taken in the mass interval 2.9 to 4.5 GeV. SIG/SIG ratio are free from most systematic errors.

More…