TY - JOUR
T1 - Hiding relativistic degrees of freedom in the early universe
AU - Barger, V.
AU - Kneller, James P.
AU - Langacker, Paul
AU - Marfatia, Danny
AU - Steigman, Gary
N1 - Funding Information:
We thank K. Abazajian, G. Fuller and Y. Wong for enlightening discussions. This research was supported by the US DOE under Grants Nos. DE-FG02-95ER40896, DE-FG02-91ER40676, DE-FG0291ER40690, DE-FG02-02ER41216, and DOE-EY-76-02-3071, by the NSF under Grant No. PHY99-07949, and by the Wisconsin Alumni Research Foundation. V.B., P.L., D.M. and G.S. thank the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara, for its support and hospitality.
PY - 2003/9/11
Y1 - 2003/9/11
N2 - We quantify the extent to which extra relativistic energy density can be concealed by a neutrino asymmetry without conflicting with the baryon asymmetry measured by the Wilkinson Microwave Anisotropy Probe (WMAP). In the presence of a large electron neutrino asymmetry, slightly more than seven effective neutrinos are allowed by Big Bang Nucleosynthesis (BBN) and WMAP at 2σ. The same electron neutrino degeneracy that reconciles the BBN prediction for the primordial helium abundance with the observationally inferred value also reconciles the LSND neutrino with BBN by suppressing its thermalization prior to BBN.
AB - We quantify the extent to which extra relativistic energy density can be concealed by a neutrino asymmetry without conflicting with the baryon asymmetry measured by the Wilkinson Microwave Anisotropy Probe (WMAP). In the presence of a large electron neutrino asymmetry, slightly more than seven effective neutrinos are allowed by Big Bang Nucleosynthesis (BBN) and WMAP at 2σ. The same electron neutrino degeneracy that reconciles the BBN prediction for the primordial helium abundance with the observationally inferred value also reconciles the LSND neutrino with BBN by suppressing its thermalization prior to BBN.
UR - http://www.scopus.com/inward/record.url?scp=0041693919&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0041693919&partnerID=8YFLogxK
U2 - 10.1016/j.physletb.2003.07.039
DO - 10.1016/j.physletb.2003.07.039
M3 - Article
AN - SCOPUS:0041693919
SN - 0370-2693
VL - 569
SP - 123
EP - 128
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 3-4
ER -