Thermal Dileptons from pi - rho Interactions in a Hot Pion Gas

Abstract

A systematic study of low mass dilepton production from $\pi -\rho$ interactions in a hot medium is presented. Applying finite temperature perturbation theory the dilepton rate, respectively the virtual photon rate, is computed up to order $g_{\rho }^2$. For dilepton masses below the $\rho$ the two-body reactions $\pi \pi \to \rho {\gamma }^{\ast }$, $\pi \rho \to \pi {\gamma }^{\ast }$, and the decay process $\rho \to \pi \pi {\gamma }^{\ast }$ give significant contributions. Non-equilibrium contributions to the thermal rate are estimated, including the modification of the particle distribution function with non-zero pion chemical potential. The comparison of the dilepton rate with the recent data measured in nucleus-nucleus collisions at SPS energy by the CERES Collaboration is also performed. It is shown that the additional thermal dileptons from $\pi -\rho$ interactions can partially account for the access of the soft dilepton yield seen experimentally.

arXiv comment21 pages LaTeX, 8 figs with epsfig.sty macro included

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Cited by in corpus (20)

• Signatures of Quark-Gluon-Plasma formation in high energy heavy-ion collisions: A critical review
• Hadronic scattering of charmed mesons
• Properties of Hadrons in the Nuclear Medium
• Thermal photon production rate from non-equilibrium quantum field theory
• Fermionic Collective Modes of an Anisotropic Quark-Gluon Plasma
• Low-mass dileptons and dropping rho meson mass
• Charm meson scattering cross sections by pion and rho meson
• Intermediate-mass dilepton spectra and the role of secondary hadronic processes in heavy-ion collisions
• Two mechanisms for the elimination of pinch singularities in out of equilibrium thermal field theories
• Dilepton and Photon Emission Rates from a Hadronic Gas III
• Inertial mechanism: dynamical mass as a source of particle creation
• Out of Equilibrium Thermal Field Theories - Finite Time after Switching on the Interaction - Wigner Transforms of Projected Functions
• Equation of State of Hadronic matter and Electromagnetic Radiation from Relativisitic Heavy Ion Collisions
• Low-mass dileptons at the SPS
• Open Charm, Photon and Dilepton Production in an Increasingly Strongly Interacting Parton Plasma
• Chemical nonequilibrium for interacting bosons: applications to the pion gas
• rho -> pi pi decay in nuclear medium
• Photon production in heavy-ion collisions at SPS energies
• $\rho$ meson broadening and dilepton production in heavy ion collisions
• Dielectron Production in Heavy Ion Collisions at 158 GeV/c per Nucleon