Photon and di-lepton emission from the quark-gluon plasma: some general considerations

Technical Report · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6128306

McLerran, L D; Toimela, T

The emission rates for photons and di-leptons from a quark-gluon plasma is related to the thermal expectation value of an electromagnetic current-current correlation function. This correlation function possesses an invariant tensor decomposition with structure functions entirely analogous to W/sub 1/ and W/sub 2/ of deep inelastic scattering of leptons from hadronic targets. The thermal scaling properties of the appropriate structure functions for thermal emission are derived. The thermal structure functions may be computed in a weak coupling expansion at high plasma temperature. The rates for thermal emission are estimated, and for di-leptons, the thermal emissions rate is argued to dominate over the Drell-Yan process for di-lepton masses 600 MeV < M < 1 to 2 GeV using conservative estimates of the plasma temperature. We argue that higher temperatures are entirely possible within the context of the inside-outside cascade model of matter formation, perhaps temperatures as high as 500 to 800 MeV. If these high temperatures are achieved, the maximum di-lepton masses arising from thermal emission are argued to be 5 GeV. Signals for thermal emission are presented as the relative magnitude of invariant thermal structure functions, thermal scaling relations, and transverse momenta of thermal di-lepton pairs increasing with and proportional to the di-lepton pair mass. The transverse mass spectra is given for a high temperature plasma. The dependence of the spectra of thermal emission upon the existence of a first phase transition is studied. We argue that if there is a first order phase transition, as beam energy or nuclear baryon number is raised through the threshold for production of a plasma, the rate for photon or di-lepton emission might dramatically increase.

• Research Organization: Washington Univ., Seattle (USA). Dept. of Physics
• DOE Contract Number: AC06-81ER40048
• OSTI ID: 6128306
• Report Number(s): DOE/ER/40048-13-P4; ON: DE85007835
• Country of Publication: United States
• Language: English

Related Subjects

645201 -- High Energy Physics-- Particle Interactions &amp; Properties-Theoretical-- General &amp; Scattering Theory
653002* -- Nuclear Theory-- Nuclear Matter
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CHARGED-PARTICLE REACTIONS
CORRELATION FUNCTIONS
DRELL MODEL
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION
EMISSION SPECTRA
FERMIONS
FUNCTIONS
HEAVY ION REACTIONS
INTERACTIONS
LEPTONS
MASSLESS PARTICLES
MATTER
NUCLEAR REACTIONS
PAIR PRODUCTION
PARTICLE PRODUCTION
PHASE TRANSFORMATIONS
PHOTONS
PROBES
QUARK MATTER
RADIATIONS
SCALING LAWS
SPECTRA
STRUCTURE FUNCTIONS
THERMAL RADIATION