A D Dolgov et al JCAP06(2005)004 doi:10.1088/1475-7516/2005/06/004
A D Dolgov1,2, S H Hansen3 and A Yu Smirnov4,5
Show affiliationsNeutrinos may possibly violate the spin-statistics theorem, and hence obey Bose statistics or mixed statistics despite having spin half. We find the generalized equilibrium distribution function of neutrinos which depends on a single Fermi–Bose parameter, κ, and interpolates continuously between the bosonic and fermionic distributions when κ changes from −1 to +1. We consider modification of the big bang nucleosynthesis (BBN) in the presence of bosonic or partly bosonic neutrinos. For pure bosonic neutrinos the abundances change (in comparison with the usual Fermi–Dirac case) by −3.2% for 4He (which is equivalent to a decrease of the effective number of neutrinos by ΔNν≈−0.6), +2.6% for 2H, and −7% for 7Li. These changes provide a better fit to the BBN data. Future BBN studies will be able to constrain the Fermi–Bose parameter to κ>0.5, if no deviation from fermionic nature of neutrinos is found. We also evaluate the sensitivity of future CMB and LSS observations to the Fermi–Bose parameter.
Issue 06 (June 2005)
Received 11 April 2005, accepted for publication 1 June 2005
Published 9 June 2005
A D Dolgov et al JCAP06(2005)004
Tzenka Miteva et al 2008 New J. Phys. 10 103002
M J Kushner 2009 Plasma Sources Sci. Technol. 18 010101
Elsa Batista and Peter Lau 2009 Metrologia 46 07013
Phill Gu Jung et al 2008 J. Micromech. Microeng. 18 035017
Jacques Distler and Frederic Zamora JHEP05(2000)005
Adrian Keller et al 2008 New J. Phys. 10 063004
R F Fernsler 2009 Plasma Sources Sci. Technol. 18 014012
Michele Caselle et al JHEP11(2007)075
G Ratel and C Michotte 2004 Metrologia 41 06013