| Autor: |
Abreu, M. C., Alessandro, B., Alexa, C., Arnaldi, R., Astruc, J., Ataian, M., Baglin, C., Baldit, A., Bedjidian, M., Bellaiche, F., Beole, S., Boldea, V., Bordalo, P., Bussiere, A., Capony, V., Casagrande, L., Castor, J., Chambon, T., Chaurand, B., Chevrot, I., Cheynis, B., Chiavassa, E., Cicalo, C., Comets, M. P., Constantinescu, S., Cruz, J., Falco, A., Marco, N., Dellacasa, G., Devaux, A., Dita, S., Drapier, O., Espagnon, B., Fargeix, J., Filippov, S. N., Fleuret, F., Force, P., Gallio, M., Gavrilov, Yu K., Gerschel, C., Giubellino, P., Golubeva, M. B., Gonin, M., Grigorian, A. A., Grossiord, J. Y., Guber, F. F., Guichard, A., Gulkanian, H., Hakobian, R., Haroutunian, R., Idzik, M., Jouan, D., Karavicheva, T. L., Kluberg, L., Kurepin, A. B., Le Bornec, Y., Lourenco, C., Maccormick, M., Macciotta, P., Marzari-Chiesa, A., Masera, M., Masoni, A., Megrabian, S. S., Mourgues, S., Musso, A., Malek, Fairouz, Petiau, P., Piccotti, A., Pizzi, J. R., Prado Da Silva, W. L., Puddu, G., Quintans, C., Racca, C., Ramello, L., Ramos, S., Rato-Mendes, P., Riccati, L., Romana, A., Sartori, S., Saturnini, P., Scomparin, E., Serci, S., Shahoian, R., Silva, S., Soave, C., Sonderegger, P., Tarrago, X., Temnikov, P., Topilskaya, N. S., Gianluca Usai, Vale, C., Vercellin, E., Willis, N. |
| Jazyk: |
angličtina |
| Rok vydání: |
1999 |
| Předmět: |
|
| Zdroj: |
INSPIRE-HEP |
| Popis: |
The NA38/NA50 experiments have measured, at the CERN SPS, the dimuon production in proton-nucleus and nucleus-nucleus collisions. In this paper it is shown that the mass continuum between the $\phi$ and the $J/{\psi}$ can be satisfactorily described, after having removed the combinatorial background due to uncorrelated $\pi$ and $K$ decays, as a sum of two contributions, namely the Drell-Yan process and the semi-leptonic decay of pairs of charmed mesons, whose mass shape in the acceptance of the experiment has been evaluated using PYTHIA. However, in order to describe the A - B (namely S - U and Pb - Pb) mass spectra, the dimuon yield from open charm decays, which in $p$ - A collisions is found to be consistent with direct open charm measurements from other CERN and FNAL experiments, has to be enhanced with respect to a linear extrapolation of $p$ - A results. The size of the enhancement smoothly increases from peripheral S - U to central Pb - Pb interactions, reaching a factor $\sim$ 3 in central Pb - Pb collisions. The $P_{T}$ distributions of the events in the mass continuum are also compatible with the hypothesis of open charm enhancement in A - B collisions. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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