Astrophysical axion bounds diminished by screening effects
''Invisible axions'' could be produced in stellar interiors through Compton- and Primakoff-type photoproduction and through bremsstrahlung processes. We point out that in a plasma screening effects lead to important reductions of these emission rates. Limits on the axion mass and interaction strength are thereby relaxed to values less restrictive than limits previously thought to be firm. For the case of the Sun the Primakoff rate is reduced by two orders of magnitude. This process is the dominant emission mechanism for Kim-Shifman-Vainshtein-Zakharov- (KSVZ) type axions which do not couple directly to electrons. The mass limit is then relaxed by an order of magnitude to m/sub a/<20 eV. Dine-Fischler-Srednicki (DFS) axions couple directly to electrons and the dominant solar emission process becomes bremsstrahlung from electron-nucleus and electron-electron collisions while the previously thought dominant Primakoff rate is now suppressed. The mass limit accidentally remains at m/sub a/<3 eV. Model-dependent bounds based on axion emission from red giants are m/sub a/<1 eV (KSVZ) and m/sub a/<0.06 eV (DFS). The mass limits for the DFS axions are understood for the special case where the free parameter 2 cosSUS of the model equals unity. Our results can be easily translated to other hypothetical pseudoscalar particles if they are light compared with typical stellar temperatures.
- Research Organization:
- Max-Planck-Institut fuer Physik und Astrophysik, Werner-Heisenberg-Institut fuer Physik, Postfach 401212, D-8000 Muenchen 40, Munich, Federal Republic of Germany
- OSTI ID:
- 6282573
- Journal Information:
- Phys. Rev. D; (United States), Vol. 33:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AXIONS
PHOTOPRODUCTION
STELLAR RADIATION
ASTROPHYSICS
BREMSSTRAHLUNG
COMPTON EFFECT
LIMITING VALUES
MASS
PLASMA
PRIMAKOFF EFFECT
SCREENING
BASIC INTERACTIONS
BOSONS
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
GOLDSTONE BOSONS
INTERACTIONS
PARTICLE PRODUCTION
POSTULATED PARTICLES
RADIATIONS
SCATTERING
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources
645202 - High Energy Physics- Particle Interactions & Properties-Theoretical- Electromagnetic Interactions & Properties