相关论文: Constraining the variation of the coupling constan…
We reconsider several current bounds on the variation of the fine-structure constant in models where all gauge and Yukawa couplings vary in an interdependent manner, as would be expected in unified theories. In particular, we re-examine the…
We put bounds on the variation of the value of the fine structure constant $\alpha$, at the time of Big Bang nucleosynthesis. We study carefully all light elements up to $^7$Li. We correct a previous upper limit on $|\Delta \alpha /…
Unification of the gauge couplings would imply that time variations of the fine structure constant are accompanied by calculable and very significant time variations in the QCD scale parameter $\Lambda_{QCD}$. Since $\Lambda_{QCD}$ is the…
The effect of variations of the fundamental nuclear parameters on big-bang nucleosynthesis are modeled and discussed in detail taking into account the interrelations between the fundamental parameters arising in unified theories.…
We reconsider the Re187 bound on the variation of the fine-structure constant. We combine the meteoritic measurement with several present-day lab measurements to firmly establish the quantitative upper limit to the time variation over the…
Astrophysical indications that the fine structure constant has undergone a small time variation during the cosmological evolution are discussed within the framework of the standard model of the electroweak and strong interactions and of…
We calculate bounds on the variation of the fine structure constant at the time of primordial nucleosynthesis and at the time of neutral hydrogen formation. We use these bounds and other bounds from the late universe to test Bekenstein…
We discuss the coupled variations of the gravitational, strong and electroweak coupling constants and the current knowledge of the nuclear equation of state based on heavy ion collision experiments and neutron star mass-radius relationship.…
Astrophysical indications that the fine structure constant is time dependent are discussed in the framework of grand unification models. A variation of the electromagnetic coupling constant could either be generated by a corresponding time…
We investigate the triple-alpha process and the Oklo phenomenon to obtain constraints on possible cosmological time variations of fundamental constants. Specifically we study cosmological temporal constraints for the fine structure constant…
Astrophysical indications that the fine structure constant has undergone a small time variation during the cosmological evolution are discussed within the framework of the standard model of the electroweak and strong interactions and of…
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…
Starting from astrophysical indications that the fine structure constant might undergo a small cosmological time shift, we discuss the implications of such an effect from the point of view of particle physics. Grand unification implies…
We consider the space-time variation of gauge couplings in brane-world models induced by the coupling to a bulk scalar field. A variation is generated by the running of the gauge couplings with energy and a conformal anomaly while going…
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…
Astrophysical indications that the fine structure constant has undergone a small time variation during the cosmological evolution are discussed within the framework of the standard model of the electroweak and strong interactions and of…
Constraint on spin-dependent and spin-independent Yukawa potential at atomic scale is developed. That covers constraints on a coupling constant of an additional photon $\gamma^*$ and a pseudovector boson. The mass range considered is from…
We study the dependence of the primordial nuclear abundances as a function of the electromagnetic fine-structure constant $\alpha$, keeping all other fundamental constants fixed. We update the leading nuclear reaction rates, in particular…
Scalar dark matter can interact with Standard Model (SM) particles, altering the fundamental constants of Nature in the process. Changes in the fundamental constants during and prior to Big Bang nucleosynthesis (BBN) produce changes in the…
We extend a recently developed Big Bang Nucleosynthesis (BBN) code, {\tt PRyMordial}, to constrain a broad class of Grand Unified Theories to which BBN is sensitive, since these lead to varying fundamental couplings. A previously developed…