A big bang nucleosynthesis likelihood analysis of the baryon-to-photon ratio and the number of light particle degrees of freedom

Keith A. Olive; David Thomas

doi:10.1016/S0927-6505(97)00008-X

A big bang nucleosynthesis likelihood analysis of the baryon-to-photon ratio and the number of light particle degrees of freedom

Keith A. Olive, David Thomas

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

We extend the model-independent likelihood analysis of big bang nucleosynthesis (BBN) based on ⁴He and ⁷Li to allow for numbers of degrees of freedom which differ from the standard model value characterized by N_v = 3. We use the two-dimensional likelihood functions to simultaneously constrain the baryon-to-photon ratio and the number of light neutrinos. The upper limit thus obtained is N_v < 4.0 (at 95% C.L.). We also consider the consequences if recent observations of deuterium in high-redshift QSO absorption-line systems (QSOALS) are confirmed.

Original language	English (US)
Pages (from-to)	27-34
Number of pages	8
Journal	Astroparticle Physics
Volume	7
Issue number	1-2
DOIs	https://doi.org/10.1016/S0927-6505(97)00008-X
State	Published - Jun 1997

Bibliographical note

Funding Information:
We thankC . Copi, B. Fields,K . Kainulainena, nd T. Walker for usefulc onversationsT.h is work was supported in part by DOE grant DE-FG02-94ER40823a t Minnesota,a nd by NASA grant NAG5-2835a t Florida.

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title = "A big bang nucleosynthesis likelihood analysis of the baryon-to-photon ratio and the number of light particle degrees of freedom",

abstract = "We extend the model-independent likelihood analysis of big bang nucleosynthesis (BBN) based on 4He and 7Li to allow for numbers of degrees of freedom which differ from the standard model value characterized by Nv = 3. We use the two-dimensional likelihood functions to simultaneously constrain the baryon-to-photon ratio and the number of light neutrinos. The upper limit thus obtained is Nv < 4.0 (at 95% C.L.). We also consider the consequences if recent observations of deuterium in high-redshift QSO absorption-line systems (QSOALS) are confirmed.",

author = "Olive, {Keith A.} and David Thomas",

note = "Funding Information: We thankC . Copi, B. Fields,K . Kainulainena, nd T. Walker for usefulc onversationsT.h is work was supported in part by DOE grant DE-FG02-94ER40823a t Minnesota,a nd by NASA grant NAG5-2835a t Florida.",

year = "1997",

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doi = "10.1016/S0927-6505(97)00008-X",

language = "English (US)",

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T1 - A big bang nucleosynthesis likelihood analysis of the baryon-to-photon ratio and the number of light particle degrees of freedom

AU - Olive, Keith A.

AU - Thomas, David

N1 - Funding Information: We thankC . Copi, B. Fields,K . Kainulainena, nd T. Walker for usefulc onversationsT.h is work was supported in part by DOE grant DE-FG02-94ER40823a t Minnesota,a nd by NASA grant NAG5-2835a t Florida.

PY - 1997/6

Y1 - 1997/6

N2 - We extend the model-independent likelihood analysis of big bang nucleosynthesis (BBN) based on 4He and 7Li to allow for numbers of degrees of freedom which differ from the standard model value characterized by Nv = 3. We use the two-dimensional likelihood functions to simultaneously constrain the baryon-to-photon ratio and the number of light neutrinos. The upper limit thus obtained is Nv < 4.0 (at 95% C.L.). We also consider the consequences if recent observations of deuterium in high-redshift QSO absorption-line systems (QSOALS) are confirmed.

AB - We extend the model-independent likelihood analysis of big bang nucleosynthesis (BBN) based on 4He and 7Li to allow for numbers of degrees of freedom which differ from the standard model value characterized by Nv = 3. We use the two-dimensional likelihood functions to simultaneously constrain the baryon-to-photon ratio and the number of light neutrinos. The upper limit thus obtained is Nv < 4.0 (at 95% C.L.). We also consider the consequences if recent observations of deuterium in high-redshift QSO absorption-line systems (QSOALS) are confirmed.

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