Fundamental Constant Observational Bounds on the Variability of the QCD Scale

Many physical theories beyond the Standard Model predict time variations of basic physics parameters. Direct measurement of the time variations of these parameters is very difficult or impossible to achieve. By contrast, measurements of fundamental constants are relatively easy to achieve, both in the laboratory and by astronomical spectra of atoms and molecules in the early universe. In this work measurements of the proton to electron mass ratio $\mu$ and the fine structure constant $\alpha$ are combined to place mildly model dependent limits on the fractional variation of the Quantum Chromodynamic Scale and the sum of the fractional variations of the Higgs Vacuum Expectation Value and the Yukawa couplings on time scales of more than half the age of the universe. The addition of another model parameter allows the fractional variation of the Higgs VEV and the Yukawa couplings to be computed separately. Limits on their variation are found at the level of less than $5 \times 10^{-5}$ over the past seven gigayears. A model dependent relation between the expected fractional variation of $\alpha$ relative to $\mu$ tightens the limits to $10^{-7}$ over the same time span. Limits on the present day rate of change of the constants and parameters are then calculated using slow roll quintessence. A primary result of this work is that studies of the dimensionless fundamental constants such as $\alpha$ and $\mu$, whose values depend on the values of the physics parameters, are excellent monitors of the limits on the time variation of these parameters.Comment: Accepted for publication in the Monthly Notices of the Royal Astronomical Society, 8 pages, 5 figure

The Relation Between Fundamental Constants and Particle Physics Parameters

The observed constraints on the variability of the proton to electron mass ratio $\mu$ and the fine structure constant $\alpha$ are used to establish constraints on the variability of the Quantum Chromodynamic Scale and a combination of the Higgs Vacuum Expectation Value and the Yukawa couplings. Further model dependent assumptions provide constraints on the Higgs VEV and the Yukawa couplings separately. A primary conclusion is that limits on the variability of dimensionless fundamental constants such as $\mu$ and $\alpha$ provide important constraints on the parameter space of new physics and cosmologies.Comment: Published in the proceedings of the Conference on Varying Constants and Fundamental Cosmology VARCOSMOFUN16. Modified from the Universe style to process properly in arXi

Confronting Cosmology and New Physics with Fundamental Constants

The values of the fundamental constants such as $\mu = m_P/m_e$, the proton to electron mass ratio and $\alpha$, the fine structure constant, are sensitive to the product $\sqrt{\zeta_x^2(w+1)}$ where $\zeta_x$ is a coupling constant between a rolling scalar field responsible for the acceleration of the expansion of the universe and the electromagnetic field with x standing for either $\mu$ or $\alpha$. The dark energy equation of state $w$ can assume values different than $-1$ in cosmologies where the acceleration of the expansion is due to a scalar field. In this case the value of both $\mu$ and $\alpha$ changes with time. The values of the fundamental constants, therefore, monitor the equation of state and are a valuable tool for determining $w$ as a function of redshift. In fact the rolling of the fundamental constants is one of the few definitive discriminators between acceleration due to a cosmological constant and acceleration due to a quintessence rolling scalar field. $w$ is often given in parameterized form for comparison with observations. In this manuscript the predicted evolution of $\mu$, is calculated for a range of parameterized equation of state models and compared to the observational constraints on $\Delta \mu / \mu$. We find that the current limits on $\Delta \mu / \mu$ place significant constraints on linear equation of state models and on thawing models where $w$ deviates from $-1$ at late times. They also constrain non-dynamical models that have a constant $w$ not equal to $-1$. These constraints are an important compliment to geometric tests of $w$ in that geometric tests are sensitive to the evolution of the universe before the epoch of observation while fundamental constants are sensitive to the evolution of the universe after the observational epoch. Abstract truncated.Comment: To appear in the conference proceedings of the Sesto Conference on Fundamental Constants and Coupling

Beta Function Quintessence Cosmological Parameters and Fundamental Constants I: Power and Inverse Power Law Dark Energy Potentials

This investigation explores using the beta function formalism to calculate analytic solutions for the observable parameters in rolling scalar field cosmologies. The beta function in this case is the derivative of the scalar $\phi$ with respect to the natural log of the scale factor $a$, $\beta(\phi)=\frac{d \phi}{d \ln(a)}$. Once the beta function is specified, modulo a boundary condition, the evolution of the scalar $\phi$ as a function of the scale factor is completely determined. A rolling scalar field cosmology is defined by its action which can contain a range of physically motivated dark energy potentials. The beta function is chosen so that the associated "beta potential" is an accurate, but not exact, representation of the appropriate dark energy model potential. The basic concept is that the action with the beta potential is so similar to the action with the model potential that solutions using the beta action are accurate representations of solutions using the model action. The beta function provides an extra equation to calculate analytic functions of the cosmologies parameters as a function of the scale factor that are that are not calculable using only the model action. As an example this investigation uses a quintessence cosmology to demonstrate the method for power and inverse power law dark energy potentials. An interesting result of the investigation is that the Hubble parameter H is almost completely insensitive to the power of the potentials and that $\Lambda$CDM is part of the family of quintessence cosmology power law potentials with a power of zero.Comment: Accepted for publication by the Monthly Notices of the Royal Astronomical Societ

Constraining cosmologies with fundamental constants I. Quintessence and K-Essence

Many cosmological models invoke rolling scalar fields to account for the observed acceleration of the expansion of the universe. These theories generally include a potential V(phi) which is a function of the scalar field phi. Although V(phi) can be represented by a very diverse set of functions, recent work has shown the under some conditions, such as the slow roll conditions, the equation of state parameter w is either independent of the form of V(phi) or is part of family of solutions with only a few parameters. In realistic models of this type the scalar field couples to other sectors of the model leading to possibly observable changes in the fundamental constants such as the fine structure constant alpha and the proton to electron mass ratio mu. This paper explores the limits this puts on the validity of various cosmologies that invoke rolling scalar fields. We find that the limit on the variation of mu puts significant constraints on the product of a cosmological parameter w+1 times a new physics parameter zeta_mu^2, the coupling constant between mu and the rolling scalar field. Even when the cosmologies are restricted to very slow roll conditions either the value of zeta_mu must be at the lower end of or less than its expected values or the value of w+1 must be restricted to values vanishingly close to 0. This implies that either the rolling scalar field is very weakly coupled with the electromagnetic field, small zeta_mu, very weakly coupled with gravity, w+1 ~ 0 or both. These results stress that adherence to the measured invariance in mu is a very significant test of the validity of any proposed cosmology and any new physics it requires. The limits on the variation of mu also produces a significant tension with the reported changes in the value of alpha.Comment: Accepted for publication in MNRAS 10 pages, 6 figure

High Redshift Candidates and the Nature of Small Galaxies in the Hubble Deep Field

We present results on two related topics: 1. A discussion of high redshift candidates (z>4.5), and 2. A study of very small galaxies at intermediate redshifts, both sets being detected in the region of the northern Hubble Deep Field covered by deep NICMOS observations at 1.6 and 1.1 microns. The high redshift candidates are just those with redshift z>4.5 as given in the recent catalog of Thompson, Weymann and Storrie-Lombardi, while the ``small galaxy'' sample is defined to be those objects with isophotal area <= 0.2 squ. arcsec and with photometric redshifts 1<z<4.5. Of the 19 possible high redshift candidates listed in the Thompson et al. catalog, 11 have (nominal) photometric redshifts less than 5.0. Of these, however, only 4 are ``robust'' in the sense of yielding high redshifts when the fluxes are randomly perturbed with errors comparable to the estimated measuring error in each wave band. For the 8 other objects with nominal photometric redshifts greater than 5.0, one (WFPC2 4--473) has a published spectroscopic redshift. Of the remaining 7, 4 are robust in the sense indicated above. Two of these form a close pair (NIC 586 and NIC 107). The redshift of the object having formally the highest redshift, at 6.56 (NIC118 = WFPC2 4--601), is problematic, since F606W and F814W flux are clearly present, and the nature of this object poses a dilemma. (abridged)Comment: 44 pages, 12 figures, to appear in ApJ v591, July 10, 200

Evidence for a Z < 8 Origin of the Source Subtracted Near Infrared Background

This letter extends our previous fluctuation analysis of the near infrared background at 1.6 microns to the 1.1 micron (F110W) image of the Hubble Ultra Deep field. When all detectable sources are removed the ratio of fluctuation power in the two images is consistent with the ratio expected for faint, z<8, sources, and is inconsistent with the expected ratio for galaxies with z>8. We also use numerically redshifted model galaxy spectral energy distributions for 50 and 10 million year old galaxies to predict the expected fluctuation power at 3.6 microns and 4.5 microns to compare with recent Spitzer observations. The predicted fluctuation power for galaxies at z = 0-12 matches the observed Spitzer fluctuation power while the predicted power for z>13 galaxies is much higher than the observed values. As was found in the 1.6 micron (F160W) analysis the fluctuation power in the source subtracted F110W image is two orders of magnitude below the power in the image with all sources present. This leads to the conclusion that the 0.8--1.8 micron near infrared background is due to resolved galaxies in the redshift range z<8, with the majority of power in the redshift range of 0.5--1.5.Comment: Accepted for publication in the Astrophysical Journa