Precision rates for nucleon weak interactions in primordial nucleosynthesis and 4He abundance

Esposito, Salvatore; Mangano, G.; Miele, Gennaro; Pisanti, O.

doi:10.1016/s0550-3213(98)00757-3

Cited by 38 publications

(49 citation statements)

References 44 publications

(89 reference statements)

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“…The calculation for the order αG 2 F corrections to the Born approximation for the energy loss rate proceeds in close analogy with what has been described in Ref.s [24,25] for a very similar situation. In particular, the additional contributions to Q due to mass, wave function and vertex corrections come from the interference between diagrams of Fig.s 1b, 1c and 1d with the Born amplitude of Fig.…”

Section: Pair Annihilation: Radiative Correctionsmentioning

confidence: 58%

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Radiative Corrections to Neutrino Energy Loss Rate in Stellar Interiors

et al. 2002

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We consider radiative electromagnetic corrections, at order α, to the process e + e − → νν at finite density and temperature. This process represents one of the main contributions to the cooling of stellar environments in the late stages of star evolution. We find that these corrections affect the energy loss rate by a factor which can be as large as −20% with respect to the tree level estimate, in the temperature and density ranges where the neutrino pair production via e + e − annihilation is the most efficient cooling mechanism.

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Section: Pair Annihilation: Radiative Correctionsmentioning

confidence: 58%

“…To regularize these divergencies we have explicitly subtracted all divergent terms expanding the squared amplitudes in a Laurent series around the pole singularities. This method follows quite closely what has been already used in [24,25,27].…”

Section: Pair Annihilation: Radiative Correctionsmentioning

confidence: 77%

Radiative Corrections to Neutrino Energy Loss Rate in Stellar Interiors

et al. 2002

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“…This has been achieved in several steps, some being already described in previous papers [8,9]. The main improvement is a complete review and update of all nuclear reaction rates which enter in the light nuclide network, as well as, more generally, a critical review of many other processes which were not considered in the standard BBN network.…”

Section: A New Code For Bbnmentioning

confidence: 99%

Present Status of Primordial Nucleosynthesis After Wmap: Results From a New BBN Code

Cuoco

Iocco

Mangano

et al. 2004

Int. J. Mod. Phys. A

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We report on the status of primordial nucleosynthesis in light of recent results on CMB anisotropies from WMAP experiment. Theoretical estimates for nuclei abundances, along with the corresponding uncertainties, are evaluated using a new numerical code, where all nuclear rates usually considered have been updated using the most recent available data. Moreover, additional processes, neglected in previous calculations, have been included. The combined analysis of CMB and primordial nucleosynthesis prediction for Deuterium gives an effective number of relativistic degrees of freedom in good agreement with the simplest scenario of three non degenerate neutrinos. Our findings seem to point out possible systematics affecting 4 He mass fraction measurements, or the effect of exotic physics, like a slightly degenerate relic neutrino background.

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“…In fact, recently, a new generation of BBN codes have been developed [3][4][5][6], which give the 4 He mass fraction Y p with a theoretical error of few per mille. This effort is justified in view of the small statistical error which is now quoted in the Y p measurements.…”

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confidence: 99%

Testing standard and degenerate big bang nucleosynthesis with BOOMERANG and MAXIMA-1

et al. 2001

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We test different Big Bang Nucleosynthesis scenarios using the recent results on the Cosmic Microwave Background Anisotropies provided by the BOOMERanG and MAXIMA-1 experiments versus the observed abundances of 4 He, D and 7 Li. The likelihood analysis, based on Bayesian approach, shows that, in the case of high deuterium abundance, YD = (2.0 ± 0.5)10 −4 , both standard and degenerate BBN are inconsistent with the CMBR measurement at more than 3σ. Assuming low deuterium abundance, YD = (3.4 ± 0.3)10 −5 , the standard BBN model is still inconsistent with present observations at 2σ level, while the degenerate BBN results to be compatible. Unless systematics effects will be found in nuclide abundances and/or in CMBR data analysis this result may be a signal in favour of new physics like a large chemical potential of the relic neutrino-antineutrino background.One of the main goals of modern cosmology is the knowledge of the energy density content of the universe. The four parameters Ω B , Ω CDM , Ω ν and Ω Λ , giving, respectively, the baryon, cold dark matter, neutrino and cosmological constant contributions to the total energy density, in unit of the critical density, and the Hubble constant, H 0 = 100h Km s −1 M pc −1 , enter as crucial parameters in several cosmological observables. A well known example is provided by the baryon density parameter which plays an essential role in determining the abundances of light nuclides produced in the early universe. An increasing interest has been also devoted to other issues, as structure formation and the anisotropy of the Cosmic Microwave Background Radiation (CMBR). As for our theoretical understanding of the Big Bang Nucleosynthesis (BBN), to test the theoretical models which describe these aspects of the hot Big Bang model, it is essential to have precise measurements of the several Ω i h 2 . Furthermore, combining different cosmological observables, and comparing the way they are able to constrain the Ω i h 2 , allows for a check of the consistency of our present understanding of the evolution of the universe. This can provide new hints on phenomena which took place at the macroscopic cosmological level, or rather related with the very microscopic structure of fundamental interactions.This letter represents a contribution in this direction. In particular, we do perform a combined analysis of the dependence on the energy fractions Ω B h 2 and Ω ν h 2 = N ν Ω 0 ν h 2 for massless neutrinos (N ν standing for the effective neutrino number and Ω 0 ν h 2 for the energy contribution of a single ν − ν specie) of CMBR anisotropies and BBN. This is aimed to test the standard and degenerate BBN scenario, using the recent results of the BOOMERanG [1] and MAXIMA-1 [2] CMBR experiments and the measurements of 4 He, D and 7 Li primordial abundances.The theoretical tools necessary to achieve this goal are nowadays rather robust and the accuracy in the predictions of the Big Bang model is remarkably improved. In fact, recently, a new generation of BBN codes have been developed [3][4]...

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Precision rates for nucleon weak interactions in primordial nucleosynthesis and 4He abundance

Cited by 38 publications

References 44 publications

Radiative Corrections to Neutrino Energy Loss Rate in Stellar Interiors

Radiative Corrections to Neutrino Energy Loss Rate in Stellar Interiors

Present Status of Primordial Nucleosynthesis After Wmap: Results From a New BBN Code

Testing standard and degenerate big bang nucleosynthesis with BOOMERANG and MAXIMA-1

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