14365154
Lorentz symmetry violation due to interactions of photons with the graviton background
The average time delay of photons due to multiple interactions with gravitons of the background is computed in a frame of the model of low-energy quantum gravity by the author. The two variants of evaluation of the lifetime of a virtual photon are considered: 1$)$ on a basis of the uncertainties relation (it is a common place in physics of particles) and 2$)$ using a conjecture about constancy of the proper lifetime of a virtual photon. It is shown that in the first case Lorentz violation is negligible: the ratio of the average time delay of photons to their propagation time is equal approximately to $10^{-28}$; in the second one (with a new free parameter of the model), the time-lag is proportional to the difference $\sqrt{E_{01}}-\sqrt{E_{02}}$, where $E_{01}, E_{02}$ are initial energies of photons, and more energetic photons should arrive later, also as in the first case. The effect of graviton pairing is taken into account, too.
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.
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 $94.576 km \cdot s^{-1} \cdot Mpc^{-1}$).
14740363
A few remarks about the Pioneer anomaly
Some features of the Pioneer anomaly are discussed in context of author’s explanation of this effect as a deceleration of the probes in the graviton background. It is noted that if the model is true then the best parameter of the anomalous acceleration should be not the distance to the Sun but a cosine of the angle between a velocity of the probe and its radius-vector.
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.
119108208
Relativistic constituent quark model with infrared confinement
We refine the relativistic constituent quark model developed in our previous papers to include the confinement of quarks. It is done, first, by introducing the scale integration in the space of {alpha} parameters, and, second, by cutting this scale integration on the upper limit which corresponds to an infrared cutoff. In this manner one removes all possible thresholds present in the initial quark diagram. The cutoff parameter is taken to be the same for all physical processes. We adjust other model parameters by fitting the calculated quantities of the basic physical processes to available experimental data. As an application, we calculate the electromagnetic form factors of the pion and the transition form factors of the {omega} and {eta} Dalitz decays.
18648204
Decay Constants and Semileptonic Form Factors of Pseudoscalar Mesons 1
AbstractA relativistic constituent quark model is adopted to give an uniﬁed description of the leptonic andsemileptonic decays of pseudoscalar mesons (π, K, D, D s , B, B s ). The calculated leptonic decayconstants and form factors are found to be in good agreement with available experimental data andthe results of other approaches. Eventually, the model is found to reproduce the scaling behavioursof spin-ﬂavor symmetry in the heavy-quark limit. 1 Introduction Semileptonic decays of pseudoscalar mesons allow to evaluate the elements of the Cabibbo–Kobayashi–Maskawa (CKM) matrix, which are fundamental parameters of the Standard Model. The decay K → πeνprovides the most accurate determination of V us , the semileptonic decays of D and B mesons, D →K(K ∗ )lν, B → D(D ∗ )lν and B → π(ρ)lν, can be used to determine |V cs |, |V cb | and |V ub |, respectively.This program can be performed if the non-perturbative QCD eﬀects, which are parameterized by theform factors, are known. Up to now, these form factors cannot be evaluated from ﬁrst principles, thusmodels, more or less connected with QCD, are usually considered for this purpose. Here we discuss arelativistic quark model [1], previously used to study the baryon form factors [2].This model is based on an eﬀective Lagrangiandescribingthe coupling ofmesons with their constituentquarks. The physical processes are described by the one-loop quark diagrams and meson-quark verticesrelated to the Bethe-Salpeter amplitudes. In principle, the vertex functions and quark propagatorsshouldbe given by the Bethe-Salpeter and Dyson-Schwinger equations, respectively. This kind of analysis isprovided by the Dyson-Schwinger Equation (DSE) studies [3] and an uniﬁed description of light andheavy meson observables was carried out in [4, 5]. Here, instead, we use free propagators for constituentquarks and consider a Gaussian vertex function as Bethe-Salpeter conﬁning function. The adjustableparameters, the widths of Bethe-Salpeter amplitudes in momentum space, and the constituent quarkmasses, are determined from the best ﬁt of available experimental data and some lattice simulations.Our results are in good agreement with experimental data and other approaches. We also reproduce thespin-ﬂavor symmetry relations and scaling for leptonic decay constants and semileptonic form factors inthe heavy-quark limit [6].An approach similar to the one presented here, can be found in [7]. That model is based on meson-quark interactions, so the mesonic transition amplitudes are described by diagrams with heavy mesonsattached to quark loops. The free propagator has been used for light quarks, while the quark propagatorobtained in the heavy-quark limit has been adopted for heavy quarks.
122927844
Nonleptonic Interactions of Kaons in the Quark Confinement Model
Nonleptonic, electromagnetic decays of K-mesons and K°–K° transition are treated with the effective Hamiltonians with ΔS = 1, 2. Matrix elements of four-quark operators are calculated in the framework of Quark Confinement Model. The account of the intermediate scalar mesons turns out to allow to explain ΔI = 1/2 rule. The account of intermediate scalar and pseudo-scalar states leads to experimental value of mass difference of KL°–KS° mesons. The obtained values for nonleptonic and electromagnetic decay widths as well as mass difference ΔmLS are in good agreement with experimental data.
122074467
The extended Nambu-Jona-Lasinio model with separable interaction: Low energy pion physics and pion-nucleon form factor
A Lagrangian formulation of the Nambu-Jona-Lasinio model with separable interaction is given. The electromagnetic interaction is introduced in a nonminimal way to the nonlocal quark current. Various choices of the vertex form factors characterizing the composite structure of mesons and baryon are investigated. We find that the physical observables depend very weakly on form factor shapes. We calculate the πNN form factor considering nucleon as a three-quark system.
118410366
Radiative decays of double heavy baryons in a relativistic constituent three-quark model including hyperfine mixing effects
We study flavor-conserving radiative decays of double-heavy baryons using a manifestly Lorentz covariant constituent three-quark model. Decay rates are calculated and compared to each other in the full theory, keeping masses finite, and also in the heavy quark limit. We discuss in some detail hyperfine mixing effects.