Abreu, Ricardo
Muon production
[0.0, 1.0]
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Study of double-tagged gamma gamma events at LEP II.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 46 (2006) 559-568, 2006.
Inspire Record 704268 DOI 10.17182/hepdata.48974

Double-tagged interactions of photons with virtualities Q^2 between 10 GeV^2 and 200 GeV^2 are studied with the data collected by DELPHI at LEPII from 1998 to 2000, corresponding to an integrated luminosity of 550 pb^{-1}. The gam* gam* -> mu+mu- data agree with QED predictions. The cross-section of the reaction gam* gam* -> hadrons is measured and compared to the LO and NLO BFKL calculations.

4 data tables
Table 1

Measured cross section for the process E+ E- --> E+ E- HADRONS.

Table 2

Measured cross section for the process GAMMA* GAMMA* --> HADRONS.

Table 3

Differential cross section for GAMMA* GAMMA* --> MU+ MU-.

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Cross-sections and leptonic forward-backward asymmetries from the Z0 running of LEP.

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J.C 16 (2000) 371-405, 2000.
Inspire Record 527605 DOI 10.17182/hepdata.49969

During 1993 and 1995 LEP was run at 3 energies near the Z$^0$peak in order to give improved measurements of the mass and width of the resonance. During 1994, LEP o

14 data tables
Table 1

Hadronic cross section measured with the 1993 data. Additional systematic error of 0.10 PCT (efficiencies and backgrounds) and 0.29 PCT (absolute luminosity).

Table 2

Hadronic cross section measured with the 1994 data. Additional systematic error of 0.11 PCT (efficiencies and backgrounds) and 0.11 PCT (absolute luminosity).

Table 3

Hadronic cross section measured with the 1995 data. Additional systematic error of 0.10 PCT (efficiencies and backgrounds) and 0.11 PCT (absolute luminosity).

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Observation of a threshold effect in the anomalous J/psi suppression.

The NA50 collaboration Abreu, M.C ; Alessandro, B ; Alexa, C ; et al.
Phys.Lett.B 450 (1999) 456-466, 1999.
Inspire Record 499915 DOI 10.17182/hepdata.49189

We report on a search for a phase transition from ordinary nuclear matter to a state of deconfined quarks and gluons as predicted by lattice QCD calculations. A new measurement of charmonium production in Pb-Pb interactions at 158 GeV/ c per nucleon agrees with our previous results and confirms the anomalous J/ ψ suppression we had already observed on a significantly smaller data sample. New event selection and analysis techniques show that, for peripheral collisions, the J/ ψ cross-section per nucleon-nucleon collision agrees with the precise suppression pattern inferred from a wide range of measurements extending from p-p up to S-U collisions. As the collisions become more central, the Pb-Pb cross-section exhibits a clear departure from this normal behaviour. The onset of the anomalous J/ ψ suppression reported here is the first clear observation of a threshold effect in heavy ion collisions and can be considered as a strong indication of the production of a deconfined quark-gluon phase in central Pb-Pb collisions.

2 data tables
Table 1

The J/PSI cross section is the cross section for decay to muon pairs.

Table 2

The J/PSI cross section is the cross section for decay to muon pairs. The ratios in this taBLE Are obtained from the minimum bias sample of events. See text if article for details.