# Low mass dimuon production in proton and ion induced interactions at SPS

6 ALICE
IP2I Lyon - Institut de Physique des 2 Infinis de Lyon
Abstract : The low mass dimuon spectra collected in p-U collisions by the NA38 experiment significantly exceeds the total cross section expected from previous analysis, done by other experiments. The excess' events have a harder \pt\ distribution than the muon pairs from $\eta$ and $\omega$ Dalitz decays, expected to dominate the mass window 0.4--0.65~GeV/$c^2$. We conjecture that the excess events might be due to \qqbar\ annihilations, negligible at low \pt\ but made visible by the \mt\ cut applied in the NA38 data. Taking this assumption to parametrise the p-U spectra, we proceed with the analysis of the S-Cu, S-U and Pb-Pb data, collected by the NA38 and NA50 experiments, where we find that the measured mass spectra does not seem to exceed the expected low mass cocktail' by more than 20\,\%.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00003710
Contributor : Sylvie Flores <>
Submitted on : Tuesday, April 11, 2000 - 12:41:42 PM
Last modification on : Tuesday, April 20, 2021 - 12:00:07 PM
Long-term archiving on: : Friday, May 29, 2015 - 4:35:16 PM

### Identifiers

• HAL Id : in2p3-00003710, version 1

### Citation

M C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, J. Astruc, et al.. Low mass dimuon production in proton and ion induced interactions at SPS. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2000, 13, pp.69-78. ⟨in2p3-00003710⟩

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