12841244
Hubble diagrams of soft and hard radiation sources in the graviton background: to an apparent contradiction between supernova 1a and gamma-ray burst observations
In the sea of super-strong interacting gravitons, non-forehead collisions with gravitons deflect photons, and this deflection may differ for soft and hard radiations. As a result, the Hubble diagram would not be a universal function and it will have a different view for such sources as supernovae in visible light and gamma-ray bursts. Observations of these two kinds are compared here with the limit cases of the Hubble diagram.
16422963
May gravitons be super-strong interacting particles?
A scheme, in which gravitons are super-strong interacting, is described. The graviton background with the Planckian spectrum and a small effective temperature is considered as a reservoir of gravitons. A cross-section of interaction of a graviton with any particle is assumed to be a bilinear function of its energies. Any pair of bodies are attracting not due to an exchange with its own gravitons, but due to a pressure of external gravitons of this background. A graviton pairing is necessary to obtain classical gravity. Any divergencies are not possible in such the model because of natural smooth cut-offs of the graviton spectrum from both sides. Some cosmological consequences of this scheme are discussed, too. Also it is shown here that the main conjecture of this approach may be verified at present on the Earth.
16526170
Small effects of low-energy quantum gravity
Small effects of quantum gravity on the scale $\sim 10^{-3} eV$ and their cosmological consequences are discussed and compared with observations of supernovae 1a, gamma-ray bursts and galaxies.
18867033
A quantum gravitational model of redshifts
The main features of an alternative model of redshifts are described here. The model is based on conjectures about an existence of the graviton background with the Planckian spectrum and a super-strong character of quantum gravitational interaction. This model is connected with the assumed quantum mechanism of gravity. A behavior of two theoretical functions of a redshift $z$ in this model - the geometrical distance $r(z)$ and the luminosity distance $D_{L}(z)$ - and an existence of two different cosmological horizons for any observer are discussed.
16705419
A Fine quantum mechanism of classical gravity
It is shown that screening the background of super-strong interacting gravitons ensures the Newtonian attraction, if a part of single gravitons is pairing and graviton pairs are destructed by collisions with a body. If the considered quantum mechanism of classical gravity is realized in the nature, than an existence of black holes contradicts to the equivalence principle. In such the model, Newton's constant is proportional to $H^{2}/T^{4},$ where $H$ is the Hubble constant, $T$ is an equivalent temperature of the graviton background. The estimate of the Hubble constant is obtained for the Newtonian limit: $H=3.026 \cdot 10^{-18} s^{-1}$ (or $94.576 km \cdot s^{-1} \cdot Mpc^{-1}$).
14410547
Model of graviton-dusty universe
Primary features of a new cosmological model, which is based on conjectures about an existence of the graviton background and superstrong gravitational quantum interaction, are considered. An expansion of the universe is impossible in such the model because of deceleration of massive objects by the graviton background, which is similar to the one for the NASA deep space probes Pioneer 10, 11. Redshifts of remote objects are caused in the model by interaction of photons with the graviton background, and the Hubble constant depends on an intensity of interaction and an equivalent temperature of the graviton background. Virtual massive gravitons would be dark matter particles. They transfer energy, lost by luminous matter radiation, which in a final stage may be collected with black holes and other massive objects.
118959015
Low-energy photon–photon collisions to two loops revisited
Abstract In view of ongoing experimental activities to determine the pion polarizabilities, we have started to recalculate the available two-loop expressions in the framework of chiral perturbation theory, because they have never been checked before. We make use of the chiral Lagrangian at order p 6 now available, and of improved techniques to evaluate the two-loop diagrams. Here, we present the result for the neutral pions. The cross section for the reaction γ γ → π 0 π 0 agrees with the earlier calculation within a fraction of a percent. We present analytic results for the dipole and quadrupole polarizabilities, and compare the latter with a recent evaluation from data on γ γ → π 0 π 0 .
15798950
Heavy quark limit in the model with confined light quarks and infrared heavy quark propagators
We calculate the weak coupling constants of B and D mesons, and the Isgur‐Wise form factor within the relativistic quark model with confined light quarks and with taking into account the infrared behavior of the heavy quark propagator. We investigate their dependence on the mass difference E=mH−MQ, and the parameter, characterizing the infrared behavior of the heavy quark propagator in the heavy quark limit. It is found that the weak decay constants depend rather strongly on the mass difference E with the infrared parameter ν being fixed. As for the Isgur‐Wise function its E dependence is found weak whereas it depends more strongly on the infrared parameter, leading to the suppression of this function at maximum recoil.
118350677
Cosmological dynamics of fourth-order gravity with a Gauss-Bonnet term
We consider the cosmological dynamics of fourth-order gravity with both f(R) and Φ(G) corrections to the Einstein gravity (G is the Gauss-Bonnet invariant). The particular case for which both terms are equally important on power-law solutions is described. These solutions and their stability are studied using the dynamic system approach. We also discuss the condition of existence and stability of a de Sitter solution in a more general situation of power-law f and Φ.
126340447
B and D meson decays with taking into account confinement of light quarks
15685350
Integrating out strange quarks in ChPT: Terms at order p6
Abstract Chiral perturbation theory in the two-flavour sector allows one to analyse Green functions in qcd in a limit where the strange quark mass is considered to be large in comparison to the external momenta and to the light quark masses m u and m d . In this framework, the low-energy constants of SU ( 2 ) R × SU ( 2 ) L depend on the value of the heavy quark masses. In a recent article, we have worked out, for the coupling constants l i which occur at order p 4 in the chiral expansion, the dependence on the strange quark mass at two-loop accuracy. Here, we provide analogous relations for some of the couplings c i which are relevant at order p 6 . To keep the calculations somewhat reasonable in size, we consider only those 28 couplings which enter the Green functions built from vector and axial vector quark currents in the chiral limit m u = m d = 0 , m s ≠ 0 . This provides the matching for 27 linear combinations of the 28 couplings.