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Cosmological lepton asymmetry, primordial nucleosynthesis and sterile neutrinos

Abazajian, Kevork and Bell, Nicole F. and Fuller, George M. and Wong, Yvonne Y. Y. (2005) Cosmological lepton asymmetry, primordial nucleosynthesis and sterile neutrinos. Physical Review D, 72 (6). Art. no. 063004. ISSN 2470-0010. doi:10.1103/PhysRevD.72.063004.

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We study post weak decoupling coherent active-sterile and active-active matter-enhanced neutrino flavor transformation in the early Universe. We show that flavor conversion efficiency at Mikheyev-Smirnov-Wolfenstein resonances is likely to be high (adiabatic evolution) for relevant neutrino parameters and energies. However, we point out that these resonances cannot sweep smoothly and continuously with the expansion of the Universe. We show how neutrino flavor conversion in this way can leave both the active and sterile neutrinos with nonthermal energy spectra, and how, in turn, these distorted energy spectra can affect the neutron-to-proton ratio, primordial nucleosynthesis, and cosmological mass/closure constraints on sterile neutrinos. We demonstrate that the existence of a light sterile neutrino which mixes with active neutrinos can change fundamentally the relationship between the cosmological lepton numbers and the primordial nucleosynthesis 4He yield.

Item Type:Article
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Abazajian, Kevork0000-0001-9919-6362
Bell, Nicole F.0000-0002-5805-9828
Additional Information:©2005 The American Physical Society (Received 8 October 2004; revised 6 May 2005; published 27 September 2005) The work of G. M. F. was supported in part by NSF Grant No. PHY-00-99499, the TSI Collaboration’s DOE SciDAC grant, and the UC/LANL CARE grant at UCSD; K. A. was supported by Los Alamos National Laboratory (under DOE Contract No. W-7405-ENG-36) and also acknowledges the UC/LANL CARE grant. N. B. was supported by Fermilab, which is operated by URA under DOE Contract No. DE-AC02-76CH03000, and was additionally supported by NASA under NAG5-10842. This research was also supported in part by the NSF under Grant No. PHY99-07949. The authors thank the ECT* and the INT at the University of Washington for hospitality. We thank Ray Volkas and Robert Foot for discussions.
Subject Keywords:cosmology; conservation laws; nucleosynthesis; cosmic ray neutrinos; neutrino oscillations
Issue or Number:6
Record Number:CaltechAUTHORS:ABAprd05
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1240
Deposited By: Archive Administrator
Deposited On:05 Jan 2006
Last Modified:08 Nov 2021 19:08

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