What to learn from dilepton transverse momentum spectra in heavy-ion collisions?

Abstract

Recently the NA60 collaboration has presented high precision measurements of dimuon spectra double differential in invariant mass $M$ and transverse pair momentum $p_T$ in In-In collisions at $158\mathrm{AGeV}$. While the $M$-dependence is important for an understanding of in-medium changes of light vector mesons and is $p_T$ integrated insensitive to collective expansion, the $p_T$-dependence arises from an interplay between emission temperature and collective transverse flow. This fact can be exploited to derive constraints on the evolution model and in particular on the contributions of different phases of the evolution to dimuon radiation into a given $M$ window. We present arguments that a thermalized evolution phase with $T>170\mathrm{MeV}$ leaves its imprint on the spectra.

arXiv commentContributed to 19th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China, 14- 20 Nov 2006

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Cited by in corpus (3)

• Evidence for radial flow of thermal dileptons in high-energy nuclear collisions
• Low Mass Dimuons Produced in Relativistic Nuclear Collisions
• Lepton-pair production in nuclear collisions - past, present, future