121682769
Electromagnetic Form Factors of Nucleons in a Relativistic Three-Quark Model
Abstract. We study electromagnetic form factors of nucleons within a relativistic three-quark model with a Gaussian shape for the nucleon-quark vertex. The allowed regions for two adjustable parameters, the range parameter ΛN in the Gaussian and the constituent quark mass mq, are obtained from fitting the data for magnetic moments and electromagnetic radii of nucleons. It is found that these observables, when calculated with mq = 420 MeV and ΛN = 1.25 GeV, agree very well with the experimental data. For these parameter values, however, our model underestimates the electromagnetic form factors of the nucleon at high momentum transfers for the calculated range O ≤ Q2≤ 1 GeV2.
121608979
Heavy baryons in the relativistic quark model
Abstract We present a summary of results for exclusive decays of single and double heavy-flavored baryons in the relativistic three-quark model.
117141257
Multiquark states in the covariant quark confinement model
This talk reviews the last applications of the covariant quark model for studying the properties of the multiquark states: B_s-meson (quark-antiquark state), light baryons (three-quark states) and tetraquark (four-quark state). The form factors of the B(B_s)-> P(V)-transitions are evaluated in the full kinematical region of momentum transfer squared. The widths of some B_s-nonleptonic decays are calculated. The static properties of the proton and neutron, and the \Lambda-hyperon (magnetic moments and charge radii) and the behavior of the nucleon form factors at low momentum transfers are described. The consequences of treating the X(3872) meson as a tetraquark bound state are explored. The decay widths of the observed channels X->J/\psi+2\pi (3\pi) and X-> \bar D^0 + D^0+\pi^0 via the intermediate off--shell states X-> J/\psi+\rho(\omega) and X-> \bar D + D^* are calculated. Its one-photon decay X-> \gamma+ J/\psi is also analyzed.
125377202
Weak decays of heavy mesons taking into account confinement of light quarks
198488906
The Box anomaly and radiative decays of eta(eta-prime) mesons
We report on a confined quark model calculation of the transition form factors for the radiative decays of \eta(\eta')->\gamma l^+l^- and \eta(\eta')->\gamma\pi^+\pi^-. The \eta-\eta' mixing angle \theta_P is determined from the set of data on the electromagnetic \eta(\eta') decays. It is found that \theta_P\sim -16.5. The analysis of the dipionic mass distribution in the decay \eta'->\gamma\pi^+\pi^- confirms the existence of a non-resonant contribution which is the box anomaly.
6599022
LEPTONIC AND SEMILEPTONIC DECAYS OF PSEUDOSCALAR MESONS
Abstract We employ the relativistic constituent quark model to give a unified description of the leptonic and semileptonic decays of pseudoscalar mesons ( π , K , D , D s , B , B s ). The calculated leptonic decay constants and form factors are found to be in good agreement with available experimental data and other approaches. We reproduce the results of spin-flavor symmetry in the heavy quark limit.
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.
119288180
A non-universal transition to asymptotic freedom in low-energy quantum gravity
The model of low-energy quantum gravity by the author has the property of asymptotic freedom at very short distances. The character of transition to asymptotic freedom is studied here. It is shown that this transition is not universal, but the one obeys the scaling rule: the range of this transition in units of $r/E^{1/2}$, where $r$ is a distance between particles and $E$ is an energy of the screening particle, is the same for any micro-particle. This range for a proton is between $10^{-11} - 10^{-13}$ meter, while for an electron it is approximately between $10^{-13} - 10^{-15}$ meter.
118722197
Testing Lorentz invariance of dark matter
We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we represent through a dynamical timelike vector field. If DM does not obey Lorentz invariance, it couples to this vector field. We find that this coupling affects the inertial mass of small DM halos which no longer satisfy the equivalence principle. For large enough lumps of DM we identify a (chameleon) mechanism that restores the inertial mass to its standard value. As a consequence, the dynamics of gravitational clustering are modified. Two prominent effects are a scale dependent enhancement in the growth of large scale structure and a scale dependent bias between DM and baryon density perturbations. The comparison with the measured linear matter power spectrum in principle allows to bound the departure from Lorentz invariance of DM at the per cent level.
7790135
Primary postulates of the standard model as consequences of the composite nature of the fundamental fermions
SummaryA field model of two-component fermions is described, the consequences of which coincide in the main with primary postulates of the standard model. Such a model can be constructed for 4 generations at the minium. Peculiarities of the relative coordinate space, determining in general an internal symmetry group, are considered. Analogues of the Higgs fields appear in the model naturally after transition to the Grassmannian extra coordinates.
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.