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The effective anisotropic stress $\eta$ is a key variable in the characterization of many classes of modified gravity theories, as it allows the testing for a long-range force additional to gravity. In this paper we forecast the precision…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Ziad Sakr , Ziyang Zheng , Santiago Casas

Various precision determinations of the Fermi constant are compared. Included are muon and (leptonic) tau decays as well as indirect prescriptions employing $\alpha, m_Z, m_W, \ssthwmzms, \Gamma(Z\to\ell^+\ell^-)$, and $\Gamma(Z \to \nu\bar…

High Energy Physics - Phenomenology · Physics 2008-11-26 William J. Marciano

It is commonly thought that small couplings in a low-energy theory, such as those needed for the fermion mass hierarchy or proton stability, must originate from symmetries in a high-energy theory. We show that this expectation is violated…

High Energy Physics - Phenomenology · Physics 2011-05-05 Nima Arkani-Hamed , Martin Schmaltz

This paper studies the critical and near-critical regimes of the planar random-cluster model on $\mathbb Z^2$ with cluster-weight $q\in[1,4]$ using novel coupling techniques. More precisely, we derive the scaling relations between the…

Probability · Mathematics 2020-12-01 Hugo Duminil-Copin , Ioan Manolescu

We present a strong constraint on variation of the proton-to-electron mass ratio, mu, over cosmological time scales using molecular hydrogen transitions in optical quasar spectra. Using high quality spectra of quasars Q0405-443, Q0347-383…

Astrophysics · Physics 2010-05-12 Julian A. King , John K. Webb , Michael T. Murphy , Robert F. Carswell

A consistent theoretical description of physics at high energies requires an assessment of vacuum stability in either the Standard Model or any extension of it. Especially supersymmetric extensions allow for several vacua and the choice of…

High Energy Physics - Phenomenology · Physics 2016-08-26 Wolfgang Gregor Hollik

We propose a new method to probe a possible time evolution of the fine structure constant $\alpha$ from X-ray and Sunyaev-Zeldovich measurements of the gas mass fraction ($f_{gas}$) in galaxy clusters. Taking into account a direct relation…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-01 R. F. L. Holanda , S. J. Landau , J. S. Alcaniz , I. E. Sanchez G. , V. C. Busti

We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network,…

Recent work by Webb {\it et al.} has provided indications of spatial variations of the fine-structure constant, $\alpha$, at a level of a few parts per million. Using a dataset of 293 archival measurements, they further show that a dipole…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-16 A. M. M. Pinho , C. J. A. P. Martins

We consider an electron-phonon system in two and three dimensions on square, hexagonal and cubic lattices. The model is a modification of the standard Holstein model where the optical branch is appropriately curved in order to have a…

Statistical Mechanics · Physics 2009-10-31 N. Macris , C. -A. Piguet

We introduce an improved model that links the frequency shift of the $^{133}\text{Cs}$ hyperfine Zeeman transitions $\vert F = 3, m_F> \longleftrightarrow \vert F = 4, m_F >$ to the Lorentz-violating Standard-Model Extension (SME)…

General Relativity and Quantum Cosmology · Physics 2017-06-01 H. Pihan-Le Bars , C. Guerlin , R. -D. Lasseri , J. -P. Ebran , Q. G. Bailey , S. Bize , E. Khan , P. Wolf

The possible cosmological variation of the proton-to-electron mass ratio was estimated by measuring the H_2 wavelengths in the high-resolution spectrum of the quasar Q~0347-382. Our analysis yielded an estimate for the possible deviation of…

Astrophysics · Physics 2009-11-07 A. Ivanchik , P. Petitjean , E. Rodriguez , D. Varshalovich

In an effort to resolve the discrepancy between two measurements of the fundamental constant mu, the proton to electron mass ratio, at early times in the universe we reanalyze the same data used in the earlier studies. Our analysis of the…

We analyse the constraints obtained from new atomic clock data on the possible time variation of the fine structure `constant' and the electron-proton mass ratio and show how they are strengthened when the seasonal variation of Sun's…

High Energy Physics - Phenomenology · Physics 2008-11-26 John D. Barrow , Douglas J. Shaw

It is shown that $\alpha_s(E)$, the strong coupling constant, can be determined in the non-perturbative regime from Bose-Einstein correlations (BEC). The obtained $\alpha_s(E)$ is in agreement with the prescriptions dealt with in the…

High Energy Physics - Phenomenology · Physics 2018-07-31 G. Alexander , B. Blok

Neutrinoless double beta decay ($0\nu\beta\beta$) is one of the most sensitive approaches to test particle physics beyond the standard model. During the last years, besides the most restrictive limit on the effective Majorana neutrino mass,…

High Energy Physics - Phenomenology · Physics 2015-06-25 H. Päs

We forecast the ability of future CMB and galaxy lensing surveys to constrain variations of the fine structure constant. We found that lensing data, as those expected from satellite experiments as Euclid could improve the constraint from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Matteo Martinelli , Eloisa Menegoni , Alessandro Melchiorri

The study of the neutrinoless double beta ($0 \beta\beta$) decay mode can provide us with important information on the neutrino properties, particularly on the electron neutrino absolute mass. In this work we revise the present constraints…

Nuclear Theory · Physics 2016-11-25 Sabin Stoica , Andrei Neacsu

We discuss how laboratory experiments can be used to place constraints on possible variations of the fine structure constant alpha in the observationally relevant redshift interval z ~= 0 - 5, within a rather general theoretical framework.…

Astrophysics · Physics 2009-10-30 Mario Livio , Massimo Stiavelli

If the reported measurements of the time variation of the fine structure constant from observations of distant QSOs are correct, combined with the Oklo limit they would strongly constrain the class of the quintessence potential. If these…

High Energy Physics - Phenomenology · Physics 2009-11-07 Takeshi Chiba , Kazunori Kohri