BBN and Lambda_QCD

Abstract

Big Bang Nucleosynthesis (BBN) has increasingly become the tool of choice for investigating the permitted variation of fundamental constants during the earliest epochs of the Universe. Here we present a BBN calculation that has been modified to permit changes in the QCD scale, Lambda_QCD. The primary effects of changing the QCD scale upon BBN are through the deuteron binding energy, B_D, and the neutron-proton mass difference, delta-m_np, which both play crucial roles in determining the primordial abundances. In this paper, we show how a simplified BBN calculation allows us to restrict the nuclear data we need to just B_D and delta-m_np yet still gives useful results so that any variation in Lambda_QCD may be constrained via the corresponding shifts in B_D and delta-m_np by using the current estimates of the primordial deuterium abundance and helium mass fraction. The simplification predicts the helium-4 and deuterium abundances to within 1% and 50% respectively when compared with the results of a standard BBN code. But Lambda_QCD also affects much of remaining required nuclear input so this method introduces a systematic error into the calculation and we find a degeneracy between B_D and delta-m_np. We show how increased understanding of the relationship of the pion mass and/or B_D to other nuclear parameters, such as the binding energy of tritium and the cross section of T + D -> He4 + n, would yield constraints upon any change in B_D and delta-m_np at the 10% level.

References added, typos corrected

References in corpus (7)

• Nuclear forces in the chiral limit
• Effective number of neutrinos and baryon asymmetry from BBN and WMAP
• The Quark-Mass Dependence of Two-Nucleon Systems
• Variation of Fundamental Couplings and Nuclear Forces
• Dependence of hadronic properties on Quark Masses and Constraints on their Cosmological Variation
• Big Bang nucleosynthesis and cosmic microwave background constraints on the time variation of the Higgs vacuum expectation value
• BBN And CMB Constraints On Dark Energy

Cited by in corpus (18)

• Primordial Nucleosynthesis: from precision cosmology to fundamental physics
• Coupled Variations of Fundamental Couplings and Primordial Nucleosynthesis
• Cosmological variation of deuteron binding energy, strong interaction and quark masses from big bang nucleosynthesis
• Life at the Interface of Particle Physics and String Theory
• Dependence of nuclear binding on hadronic mass variation
• Primordial nucleosynthesis as a probe of fundamental physics parameters
• Nucleosynthesis and the variation of fundamental couplings
• Quark mass variation constraints from Big Bang nucleosynthesis
• The variation of fundamental constants and the role of A=5 and A=8 nuclei on primordial nucleosynthesis
• Early Universe Constraints on Time Variation of Fundamental Constants
• Unifying cosmological and recent time variations of fundamental couplings
• Helium and Deuterium Abundances as a Test for the Time Variation of the Fine Structure Constant and the Higgs Vacuum Expectation Value
• The Effect of Bound Dineutrons upon BBN
• $\theta$-dependence of light nuclei and nucleosynthesis
• On the Quark Mass Dependence of Two Nucleon Observables
• Big Bang Nucleosynthesis Constraints on Universal Extra Dimensions and Varying Fundamental Constants
• Big Bang Nucleosynthesis with an Evolving Radion in the Brane World Scenario
• Big Bang Nucleosynthesis with Stable ${}^8$Be and the Primordial Lithium Problem