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Title: Dimuon radiation at relativistic energies available at the CERN Super Proton Synchrotron within a (3 + 1)D hydrodynamic + cascade model

Abstract

We analyze dilepton emission from hot and dense matter using a hybrid approach based on the ultrarelativistic quantum molecular dynamics (UrQMD) transport model with an intermediate hydrodynamic stage for the description of heavy-ion collisions at relativistic energies. During the hydrodynamic stage, the production of lepton pairs is described by radiation rates for a strongly interacting medium in thermal equilibrium. In the low-mass region, hadronic thermal emission is evaluated by assuming vector meson dominance including in-medium modifications of the {rho} meson spectral function through scattering from nucleons and pions in the heat bath. In the intermediate-mass region, the hadronic rate is essentially determined by multipion annihilation processes. Emission from quark-antiquark annihilation in the quark gluon plasma (QGP) is taken into account as well. When the system is sufficiently dilute, the hydrodynamic description breaks down and a transition to a final cascade stage is performed. In this stage dimuon emission is evaluated as commonly done in transport models. By focusing on the enhancement with respect to the contribution from long-lived hadron decays after freezeout observed at the SPS in the low-mass region of the dilepton spectra, the relative importance of the different thermal contributions and of the two dynamical stages is investigated.more » We find that three separated regions can be identified in the invariant mass spectra. Whereas the very low and the intermediate-mass regions mostly receive contribution from the thermal dilepton emission, the region around the vector meson peak is dominated by the cascade emission. Above the {rho}-peak region the spectrum is driven by QGP radiation. Analysis of the dimuon transverse mass spectra reveals that the thermal hadronic emission shows an evident mass ordering not present in the emission from the QGP. A comparison of our calculation to recent acceptance-corrected NA60 data on invariant as well as transverse mass spectra is performed.« less

Authors:
; ;  [1];  [2];  [3]
  1. Institut fuer Theoretische Physik, Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)
  2. (FIAS), Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany)
  3. Frankfurt Institute for Advanced Studies (FIAS), Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany)
Publication Date:
OSTI Identifier:
21596598
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 84; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevC.84.014901; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANNIHILATION; CERN SPS SYNCHROTRON; COMPARATIVE EVALUATIONS; EMISSION; HEAVY ION REACTIONS; LEPTONS; MASS; MASS SPECTRA; MOLECULAR DYNAMICS METHOD; NUCLEAR DECAY; PIONS; PROTONS; QUARK MATTER; QUARK-ANTIQUARK INTERACTIONS; RELATIVISTIC RANGE; SCATTERING; SPECTRAL FUNCTIONS; THERMAL EQUILIBRIUM; TRANSPORT THEORY; VECTOR MESONS; ACCELERATORS; BARYONS; BOSONS; CALCULATION METHODS; CYCLIC ACCELERATORS; DECAY; ELEMENTARY PARTICLES; ENERGY RANGE; EQUILIBRIUM; EVALUATION; FERMIONS; FUNCTIONS; HADRONS; INTERACTIONS; MATTER; MESONS; NUCLEAR REACTIONS; NUCLEONS; PARTICLE INTERACTIONS; PSEUDOSCALAR MESONS; SPECTRA; SYNCHROTRONS

Citation Formats

Santini, E., Steinheimer, J., Bleicher, M., Frankfurt Institute for Advanced Studies, and Schramm, S.. Dimuon radiation at relativistic energies available at the CERN Super Proton Synchrotron within a (3 + 1)D hydrodynamic + cascade model. United States: N. p., 2011. Web. doi:10.1103/PHYSREVC.84.014901.
Santini, E., Steinheimer, J., Bleicher, M., Frankfurt Institute for Advanced Studies, & Schramm, S.. Dimuon radiation at relativistic energies available at the CERN Super Proton Synchrotron within a (3 + 1)D hydrodynamic + cascade model. United States. doi:10.1103/PHYSREVC.84.014901.
Santini, E., Steinheimer, J., Bleicher, M., Frankfurt Institute for Advanced Studies, and Schramm, S.. Fri . "Dimuon radiation at relativistic energies available at the CERN Super Proton Synchrotron within a (3 + 1)D hydrodynamic + cascade model". United States. doi:10.1103/PHYSREVC.84.014901.
@article{osti_21596598,
title = {Dimuon radiation at relativistic energies available at the CERN Super Proton Synchrotron within a (3 + 1)D hydrodynamic + cascade model},
author = {Santini, E. and Steinheimer, J. and Bleicher, M. and Frankfurt Institute for Advanced Studies and Schramm, S.},
abstractNote = {We analyze dilepton emission from hot and dense matter using a hybrid approach based on the ultrarelativistic quantum molecular dynamics (UrQMD) transport model with an intermediate hydrodynamic stage for the description of heavy-ion collisions at relativistic energies. During the hydrodynamic stage, the production of lepton pairs is described by radiation rates for a strongly interacting medium in thermal equilibrium. In the low-mass region, hadronic thermal emission is evaluated by assuming vector meson dominance including in-medium modifications of the {rho} meson spectral function through scattering from nucleons and pions in the heat bath. In the intermediate-mass region, the hadronic rate is essentially determined by multipion annihilation processes. Emission from quark-antiquark annihilation in the quark gluon plasma (QGP) is taken into account as well. When the system is sufficiently dilute, the hydrodynamic description breaks down and a transition to a final cascade stage is performed. In this stage dimuon emission is evaluated as commonly done in transport models. By focusing on the enhancement with respect to the contribution from long-lived hadron decays after freezeout observed at the SPS in the low-mass region of the dilepton spectra, the relative importance of the different thermal contributions and of the two dynamical stages is investigated. We find that three separated regions can be identified in the invariant mass spectra. Whereas the very low and the intermediate-mass regions mostly receive contribution from the thermal dilepton emission, the region around the vector meson peak is dominated by the cascade emission. Above the {rho}-peak region the spectrum is driven by QGP radiation. Analysis of the dimuon transverse mass spectra reveals that the thermal hadronic emission shows an evident mass ordering not present in the emission from the QGP. A comparison of our calculation to recent acceptance-corrected NA60 data on invariant as well as transverse mass spectra is performed.},
doi = {10.1103/PHYSREVC.84.014901},
journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 1,
volume = 84,
place = {United States},
year = {2011},
month = {7}
}