Limits on New Superweakly Interacting Particles from Primordial Nucleosynthesis
Jun, 1980
19 pages
Published in:
- Nucl.Phys.B 180 (1981) 497-515
- Published: 1981
Report number:
- EFI-80-06-CHICAGO
Citations per year
Abstract: (Elsevier)
The existence of massless (or low mass) weakly (or superweakly) interacting particles is predicted by various models of unified theories. Such particles (neutrinos, gravitinos, gravitons) would contribute to the early expansion rate of the universe and affect the outcome of primordial nucleosynthesis. We extend previous work on the limits to the number of “ordinary” neutrinos to more weakly interacting particles which decouple earlier in the evolution of the universe. We have evaluated the limits on the number of “new” particles permitted as a function of their interaction strength. Having been forced to consider the universe at earlier times and higher temperatures than was necessary in previous discussions we have dealt, qualitatively, with the transition from free quarks to confined hadrons. We find that the maximum number of superweakly interacting, light (< 1 MeV) particles is between ∼1 and ∼20, depending on the strength of their interaction. These constraints may serve as a useful guide for new unification theories.- ASTROPHYSICS
- UNIFIED FIELD THEORY
- superweak interaction
- SUPERWEAK INTERACTION: WEAK INTERACTION
- ELECTROMAGNETIC INTERACTION
- STRONG INTERACTION
- GRAVITATION
- THERMODYNAMICS: CRITICAL PHENOMENA
- TEMPERATURE
- POSTULATED PARTICLE: WEAK INTERACTION
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