NA60 results on the rho spectral function in In-In collisions

Abstract

The NA60 experiment at the CERN SPS has studied low-mass muon pairs in 158 AGeV In-In collisions. A strong excess of pairs is observed above the yield expected from neutral meson decays. After subtraction of the decay sources, the shape of the resulting mass spectrum is largely consistent with a dominant contribution from pi+pi- -> rho -> mu+mu- annihilation. The associated rho spectral function exhibits considerable broadening, but essentially no shift in mass. The acceptance-corrected pT spectra have a shape atypical for radial flow. They also significantly depend on mass, pointing to different sources in different mass regions. Both mass and pT spectra are compared to recent theoretical predictions.

Prepared for International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2006), Asilomar, Pacific Grove, California, 9-16 Jun 2006

References in corpus (4)

• Comprehensive Interpretation of Thermal Dileptons at the SPS
• Thermal Dimuon Yields at NA60
• Dimuon transverse momentum spectra as a tool to characterize the emission region in heavy-ion collisions
• What the NA60 dilepton data can tell

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