Improved treatment of cosmic microwave background fluctuations induced by a late-decaying massive neutrino
- Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)
- Department of Physics, Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637-1433 (United States)
- NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)
A massive neutrino which decays after recombination (t{>=}10{sup 13} sec) into relativistic decay products produces an enhanced integrated Sachs-Wolfe effect, allowing constraints to be placed on such neutrinos from present cosmic microwave background anisotropy data. Previous treatments of this problem have approximated the decay products as an additional component of the neutrino background. This approach violates energy-momentum conservation, and we show that it leads to serious errors for some neutrino masses and lifetimes. We redo this calculation more accurately, by correctly incorporating the spatial distribution of the decay products. For low neutrino masses and long lifetimes, we obtain a much smaller distortion in the CMB fluctuation spectrum than have previous treatments. We combine these new results with a recent set of CMB data to exclude the mass and lifetime range m{sub h}>100 eV, {tau}>10{sup 12} sec. Masses as low as 30 eV are excluded for a narrower range in lifetime. (c) 1999 The American Physical Society.
- OSTI ID:
- 20218062
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 60, Issue 12; Other Information: PBD: 15 Dec 1999; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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