Spectral function of a fermion coupled with a massive vector boson at finite temperature in a gauge invariant formalism

Journal Article · Tue Feb 15 00:00:00 EST 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.045017· OSTI ID:21505023

Satow, Daisuke; Hidaka, Yoshimasa; Kunihiro, Teiji ^[1]

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1. Department of Physics, Faculty of Science, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan)

We investigate spectral properties of a fermion coupled with a massive gauge boson with a mass m at finite temperature (T) in the perturbation theory. The massive gauge boson is introduced as a U(1) gauge boson in the Stueckelberg formalism with a gauge parameter {alpha}. We find that the fermion spectral function has a three-peak structure for T{approx}m irrespective of the choice of the gauge parameter, while it tends to have one faint peak at the origin and two peaks corresponding to the normal fermion and antiplasmino excitations familiar in QED in the hard thermal loop approximation for T>>m. We show that our formalism successfully describe the fermion spectral function in the whole T region with the correct high-T limit except for the faint peak at the origin, although some care is needed for choice of the gauge parameter for T>>m. We clarify that for T{approx}m, the fermion pole is almost independent of the gauge parameter in the one-loop order, while for T>>m, the one-loop analysis is valid only for {alpha}<<1/g where g is the fermion-boson coupling constant, implying that the one-loop analysis cannot be valid for large gauge parameters as in the unitary gauge.

• OSTI ID: 21505023
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 4; Other Information: DOI: 10.1103/PhysRevD.83.045017; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
APPROXIMATIONS
BOSONS
COUPLING CONSTANTS
EXCITATION
FERMIONS
GAUGE INVARIANCE
MASS
PEAKS
PERTURBATION THEORY
QUANTUM ELECTRODYNAMICS
SPECTRAL FUNCTIONS
U-1 GROUPS
CALCULATION METHODS
ELECTRODYNAMICS
ENERGY-LEVEL TRANSITIONS
FIELD THEORIES
FUNCTIONS
INVARIANCE PRINCIPLES
LIE GROUPS
QUANTUM FIELD THEORY
SYMMETRY GROUPS
U GROUPS