scholarly journals WMAP 5-year constraints on α and me

2009 ◽  
Vol 5 (H15) ◽  
pp. 307-307 ◽  
Author(s):  
Claudia G. Scóccola ◽  
Susana J. Landau ◽  
Héctor Vucetich
Keyword(s):  
Statistical Analysis ◽  
Power Spectrum ◽  
Fundamental Constant ◽  
Structure Constant ◽  
Neutral Hydrogen ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Fundamental Constants ◽  
Escape Probability ◽  
Data Set

AbstractWe have studied the role of fundamental constants in an updated recombination scenario. We focus on the time variation of the fine structure constant α, and the electron mass me in the early Universe. In the last years, helium recombination has been studied in great detail revealing the importance of taking new physical processes into account in the calculation of the recombination history. The equations to solve the detailed recombination scenario can be found for example in Wong et al. 2008. In the equation for helium recombination, a term which accounts for the semi-forbidden transition 23p–11s is added. Furthermore, the continuum opacity of HI is taken into account by a modification in the escape probability of the photons that excite helium atoms, with the fitting formulae proposed Kholupenko et al 2007. We have analized the dependences of the quantities involved in the detailed recombination scenario on α and me. We have performed a statistical analysis with COSMOMC to constrain the variation of α and me at the time of neutral hydrogen formation. The observational set used for the analysis was data from the WMAP 5-year temperature and temperature-polarization power spectrum and other CMB experiments such as CBI, ACBAR and BOOMERANG and the power spectrum of the 2dFGRS. Considering the joint variation of α and me we obtain the following bounds: -0.011 < $\frac{&#x0394; &#x03B1;}{&#x03B1;_0}$ < 0.019 and -0.068 < $\frac{&#x0394; m_e}{(m_e)_0$ < 0.030 (68% c.l.). When considering only the variation of one fundamental constant we obtain: -0.010 < $\frac{&#x0394; &#x03B1;}{&#x03B1;_0$ < 0.008 and -0.04 < $\frac{&#x0394; m_e}{(m_e)_0}$ < 0.02 (68% c.l.). We compare these results with the ones presented in Landau et al 2008, which were obtained in the standard recombination scenario and using WMAP 3 year release data. The constraints are tighter in the current analysis, which is an expectable fact since we are working with more accurate data from WMAP. The bounds obtained are consistent with null variation, for both α and me, but in the present analysis, the 68% confidence limits on the variation of both constants have changed. In the case of α, the present limit is more consistent with null variation than the previous one, while in the case of me the single parameters limits have moved toward lower values. To study the origin of this difference, we have performed another statistical analysis, namely the analysis of the standard recombination scenario together with WMAP5 data, the other CMB data sets and the 2dFGRS power spectrum. We see that the change in the obtained results is due to the new WMAP data set, and not to the new recombination scenario. The obtained results for the cosmological parameters are in agreement within 1 σ with the ones obtained by the WMAP collaboration, without considering variation of fundamental constants.

scholarly journals Fundamental physics and the fine-structure constant

2017 ◽  
Vol 5 (2) ◽  
pp. 46 ◽  
Author(s):  
Michael Sherbon
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Fundamental Constants ◽  
Mass Ratio ◽  
Fundamental Physics ◽  
Weak Force ◽  
Strong Force ◽  
Symmetry Principles

From the exponential function of Euler’s equation to the geometry of a fundamental form, a calculation of the fine-structure constant and its relationship to the proton-electron mass ratio is given. Equations are found for the fundamental constants of the four forces of nature: electromagnetism, the weak force, the strong force and the force of gravitation. Symmetry principles are then associated with traditional physical measures.

scholarly journals DO THE FUNDAMENTAL CONSTANTS CHANGE WITH TIME?

2008 ◽  
Vol 23 (32) ◽  
pp. 2711-2725 ◽  
Author(s):  
NISSIM KANEKAR
Keyword(s):  
Structure Constant ◽  
Low Energy ◽  
Spectral Lines ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Fundamental Constants ◽  
Mass Ratio ◽  
Advantages And Disadvantages ◽  
Distant Galaxies ◽  
Systematic Effects

Comparisons between the redshifts of spectral lines from cosmologically-distant galaxies can be used to probe temporal changes in low-energy fundamental constants like the fine structure constant and the proton–electron mass ratio. Here, we review the results from, and the advantages and disadvantages of, the best techniques using this approach, before focussing on a new method, based on conjugate satellite OH lines, that appears to be less affected by systematic effects and hence holds much promise for the future.

scholarly journals Updated fundamental constant constraints from Planck 2018 data and possible relations to the Hubble tension

2020 ◽  
Vol 493 (3) ◽  
pp. 3255-3263 ◽  
Author(s):  
Luke Hart ◽  
Jens Chluba
Keyword(s):  
Rest Mass ◽  
Fundamental Constant ◽  
Structure Constant ◽  
Acoustic Oscillation ◽  
Fine Structure Constant ◽  
Fundamental Constants ◽  
Microwave Background ◽  
Effective Electron ◽  
Cosmological Recombination ◽  
Local Value

ABSTRACT We present updated constraints on the variation of the fine structure constant, αEM, and effective electron rest mass, me, during the cosmological recombination era. These two fundamental constants directly affect the ionization history at redshift z ≃ 1100 and, thus, modify the temperature and polarization anisotropies of the cosmic microwave background (CMB) measured precisely with Planck . The constraints on αEM tighten slightly due to improved Planck 2018 polarization data but otherwise remain similar to previous CMB analysis. However, a comparison with the 2015 constraints reveals a mildly discordant behaviour for me, which from CMB data alone is found below its local value. Adding baryon acoustic oscillation data brings me back to the fiducial value, $m_{\rm e}=(1.0078\pm 0.0067)\, m_{\rm e,0}$, and also drives the Hubble parameter to H0 = 69.1 ± 1.2(in units of ${\rm km \, s^{-1} \, Mpc^{-1} }$). Further adding supernova data yields $m_{\rm e}=(1.0190\pm 0.0055)\, m_{\rm e,0}$ with H0 = 71.24 ± 0.96. We perform several comparative analyses using the latest cosmological recombination calculations to further understand the various effects. Our results indicate that a single-parameter extension allowing a slightly increased value of me (≃3.5σ above me, 0) could play a role in the Hubble tension.

scholarly journals Testing the weak equivalence principle by differential measurements of fundamental constants in the Magellanic Clouds

2019 ◽  
Vol 487 (4) ◽  
pp. 5175-5187 ◽  
Author(s):  
S A Levshakov ◽  
K-W Ng ◽  
C Henkel ◽  
B Mookerjea ◽  
I I Agafonova ◽  
...  
Keyword(s):  
Dark Matter ◽  
Equivalence Principle ◽  
Structure Constant ◽  
Magellanic Clouds ◽  
Fine Structure Constant ◽  
Weak Equivalence ◽  
Electron Mass ◽  
Fundamental Constants ◽  
Weak Equivalence Principle ◽  
The Masses

ABSTRACT Non-standard fields are assumed to be responsible for phenomena attributed to dark energy and dark matter. Being coupled to ordinary matter, these fields modify the masses and/or charges of the elementary particles, thereby violating the weak equivalence principle. Thus, values of fundamental constants such as the proton-to-electron mass ratio, μ, and/or the fine structure constant, α, measured in different environment conditions can be used as probes for this coupling. Here we perform differential measurements of F = μα2 to test a non-standard coupling in the Magellanic Clouds–dwarf galaxies where the overall mass budget is dominated by dark matter. The analysis is based on [C i] and CO lines observed with the Herschel Space Observatory. Since these lines have different sensitivities to changes in μ and α, the combined α and μ variations can be evaluated through the radial velocity offsets, ΔV, between the CO and [C i] lines. Averaging over nine positions in the Magellanic Clouds, we obtain 〈ΔV〉 = −0.02 ± 0.07 km s−1, leading to |ΔF/F| < 2 × 10−7 (1σ), where ΔF/F = (Fobs − Flab)/Flab. However, for one position observed with five times higher spectral resolution we find ΔV = −0.05 ± 0.02 km s−1, resulting in ΔF/F = (−1.7 ± 0.7) × 10−7. Whether this offset is due to changes in the fundamental constants, due to chemical segregation in the emitting gas, or merely due to Doppler noise requires further investigations.

scholarly journals Fundamental Physics and the Fine-Structure Constant

2018 ◽  
Author(s):  
Michael A. Sherbon
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Fundamental Constants ◽  
Mass Ratio ◽  
Fundamental Physics ◽  
Weak Force ◽  
Strong Force ◽  
Symmetry Principles

From the exponential function of Euler's equation to the geometry of a fundamental form, a calculation of the fine-structure constant and its relationship to the proton-electron mass ratio is given. Equations are found for the fundamental constants of the four forces of nature: electromagnetism, the weak force, the strong force and the force of gravitation. Symmetry principles are then associated with traditional physical measures.

Searching for places where to test the variations of fundamental constants

2009 ◽  
Vol 5 (H15) ◽  
pp. 317-317
Author(s):  
P. Petitjean ◽  
P. Noterdaeme ◽  
R. Srianand ◽  
C. Ledoux ◽  
A. Ivanchik ◽  
...  
Keyword(s):  
Fine Structure ◽  
Absorption Line ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Fundamental Constants ◽  
Mass Ratio ◽  
Time Variations

AbstractIt has been realised in the last few years that strong constraints on the time-variations of dimensionless fundamental constants of physics can be derived at any redshift from QSO absorption line systems. Variations of the fine structure constant, α, the proton-to-electron mass ratio, μ, or the combination, x=α2gp/μ, where gp is the proton gyromagnetic factor, have been constrained. However, for the latter two constants, the number of lines of sight where these measurements can be performed is limited. In particular the number of known molecular and 21 cm absorbers is small. Our group has started several surveys to search for these systems. Here is a summary of some of the characteristics of these absorbers that can be used to find these systems.

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

Symmetry ◽  
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.

scholarly journals Searching for space-time variation of the fine structure constant using QSO spectra: overview and future prospects

2009 ◽  
Vol 5 (H15) ◽  
pp. 304-304
Author(s):  
J. C. Berengut ◽  
V. A. Dzuba ◽  
V. V. Flambaum ◽  
J. A. King ◽  
M. G. Kozlov ◽  
...  
Keyword(s):  
Nuclear Reactor ◽  
Structure Constant ◽  
Big Bang ◽  
The Other ◽  
Fine Structure Constant ◽  
Spatial And Temporal Variation ◽  
Fundamental Constants ◽  
Future Prospects ◽  
Big Bang Nucleosynthesis ◽  
The Universe

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)).

SPACE-TIME VARIATION OF COUPLING CONSTANTS AND FUNDAMENTAL MASSES

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3342-3353 ◽  
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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