Detecting neutrino mass difference with cosmology
- Faculty of Mathematics and Physics, University of Ljubljana (Slovenia)
Cosmological parameter estimation exercises usually make the approximation that the three standard neutrinos have degenerate mass, which is at odds with recent terrestrial measurements of the difference in the square of neutrino masses. In this paper we examine whether the use of this approximation is justified for the cosmic microwave background (CMB) spectrum, matter power spectrum, and the CMB lensing potential power spectrum. We find that, assuming {delta}m{sub 23}{sup 2}{approx}2.5x10{sup -3} eV{sup 2} in agreement with recent Earth-based measurements of atmospheric neutrino oscillations, the correction due to nondegeneracy is of the order of precision of present numerical codes and undetectable for the foreseeable future for the CMB and matter power spectra. An ambitious experiment that could reconstruct the lensing potential power spectrum to the cosmic variance limit up to l{approx}1000 will have to take the effect into account in order to avoid biases. The degeneracies with other parameters, however, will make the detection of the neutrino mass difference impossible. We also show that relaxing the bound on the neutrino mass difference will also increase the error bar on the sum of neutrino masses by a factor of up to a few. For exotic models with significantly nondegenerate neutrinos the corrections due to nondegeneracy could become important for all the cosmological probes discussed here.
- OSTI ID:
- 20774853
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 73, Issue 12; Other Information: DOI: 10.1103/PhysRevD.73.123501; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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