Big bang nucleosynthesis with a varying fine structure constant and nonstandard expansion rate

Current theories that seek to unify gravity with the other fundamental interactions suggest that spatial and temporal variation of fundamental constants is a possibility, or even a necessity, in an expanding Universe. Several studies have tried to probe the values of constants at earlier stages in the evolution of the Universe, using tools such as big-bang nucleosynthesis, the Oklo natural nuclear reactor, quasar absorption spectra, and atomic clocks (see, e.g. Flambaum & Berengut (2009)).

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SPACE-TIME VARIATION OF COUPLING CONSTANTS AND FUNDAMENTAL MASSES

International Journal of Modern Physics A ◽

10.1142/s0217751x0904693x ◽

2009 ◽

Vol 24 (18n19) ◽

pp. 3342-3353 ◽

Cited By ~ 10

Author(s):

V. V. FLAMBAUM ◽

J. C. BERENGUT

Keyword(s):

Structure Constant ◽

Big Bang ◽

Coupling Constants ◽

Fine Structure Constant ◽

Fundamental Constants ◽

Big Bang Nucleosynthesis ◽

Temporal And Spatial Variation ◽

Physical Systems ◽

Temporal And Spatial ◽

The Universe

We review recent works discussing the effects of variation of fundamental "constants" on a variety of physical systems. These are motivated by theories unifying gravity with other interactions that suggest the possibility of temporal and spatial variation of the fundamental constants in an expanding Universe. The effects of any potential variation of the fine-structure constant and fundamental masses could be seen in phenomena covering the lifespan of the Universe, from Big Bang nucleosynthesis to quasar absorption spectra to modern atomic clocks. We review recent attempts to find such variations and discuss some of the most promising new systems where huge enhancements of the effects may occur.

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NEW LIMITS ON THE FUNDAMENTAL CONSTANTS FROM THE CMB DATA

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194513011665 ◽

2013 ◽

Vol 23 ◽

pp. 391-399

Author(s):

ELOISA MENEGONI ◽

ALESSANDRO MELCHIORRI ◽

ERMINIA CALABRESE ◽

SILVIA GALLI

Keyword(s):

Fine Structure ◽

Dark Energy ◽

Structure Constant ◽

Theoretical Models ◽

Big Bang ◽

Current Data ◽

Fine Structure Constant ◽

Microwave Background ◽

Satellite Mission ◽

Cosmological Data

The Cosmic Microwave Background anisotropies provide a unique opportunity to constrain simultaneous variations of the fine-structure constant α and Newton's gravitational constant G. Those correlated variations are possible in a wide class of theoretical models. In this brief paper we show that the current data, assuming that particle masses are constant, gives no clear indication for such variations, but already prefers that any relative variations in α should be of the same sign of those of G for variations of ≈ 1%. We also show that a cosmic complementarity is present with Big Bang Nucleosynthesis, and that a combination of current CMB and BBN data strongly constraints simultaneous variations in α and G. We finally discuss the future bounds achievable by the Planck satellite mission. We discuss present and future cosmological constraints on variations of the fine structure constant α induced by an early dark energy component having the simplest allowed (linear) coupling to electromagnetism. We find that current cosmological data show no variation of the fine structure constant at recombination respect to the present-day value, with α/α0 = 0.975 ± 0.020 at 95% c.l., constraining the energy density in early dark energy to Ωe < 0.060 at 95% c.l.

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New Limit on Space-Time Variations in the Proton-to-Electron Mass Ratio from Analysis of Quasar J110325-264515 Spectra

Symmetry ◽

10.3390/sym12030344 ◽

2020 ◽

Vol 12 (3) ◽

pp. 344

Author(s):

T. D. Le

Keyword(s):

Fine Structure ◽

Structure Constant ◽

Space Time ◽

Fine Structure Constant ◽

Electron Mass ◽

Mass Ratio ◽

Quasar Spectra ◽

Time Variations ◽

Using Data ◽

The Universe

Astrophysical tests of current values for dimensionless constants known on Earth, such as the fine-structure constant, α , and proton-to-electron mass ratio, μ = m p / m e , are communicated using data from high-resolution quasar spectra in different regions or epochs of the universe. The symmetry wavelengths of [Fe II] lines from redshifted quasar spectra of J110325-264515 and their corresponding values in the laboratory were combined to find a new limit on space-time variations in the proton-to-electron mass ratio, ∆ μ / μ = ( 0.096 ± 0.182 ) × 10 − 7 . The results show how the indicated astrophysical observations can further improve the accuracy and space-time variations of physics constants.

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Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector

EPJ Web of Conferences ◽

10.1051/epjconf/201921802012 ◽

2019 ◽

Vol 218 ◽

pp. 02012

Author(s):

Graziano Venanzoni

Keyword(s):

Fine Structure ◽

Energy Region ◽

Direct Evidence ◽

Branching Ratio ◽

Structure Constant ◽

Fine Structure Constant ◽

Recent Measurement ◽

Single Measurement ◽

Lepton Universality ◽

Hadronic Contribution

I will report on the recent measurement of the fine structure constant below 1 GeV with the KLOE detector. It represents the first measurement of the running of α(s) in this energy region. Our results show a more than 5σ significance of the hadronic contribution to the running of α(s), which is the strongest direct evidence both in time-and space-like regions achieved in a single measurement. From a fit of the real part of Δα(s) and assuming the lepton universality the branching ratio BR(ω → µ+µ−) = (6.6 ± 1.4stat ± 1.7syst) · 10−5 has been determined

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