117805042
Revisiting gamma gamma --> pi+ pi- at low energies
We complete the recalculation of the available two-loop expressions for the reaction \gamma\gamma->\pi\pi in the framework of chiral perturbation theory. Here, we present the results for charged pions. The cross section and the values of the dipole polarizabilities agree very well with the earlier calculation, provided the same set of low-energy constants (LECs) is used. With updated values for the LECs at order p^4, we find for the dipole polarizabilities (\alpha_1-\beta_1)_{\pi^\pm} = (5.7\pm 1.0) 10^{-4} fm^3, which is in conflict with the experimental result recently reported by the MAMI Collaboration.
125377202
Weak decays of heavy mesons taking into account confinement of light quarks
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.
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.
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.
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.
15370571
Gravitons as super-strong interacting particles, and low-energy quantum gravity
It is shown by the author that if gravitons are super-strong interacting particles and the low-temperature graviton background exists, the basic cosmological conjecture about the Dopplerian nature of redshifts may be false. In this case, a full magnitude of cosmological redshift would be caused by interactions of photons with gravitons. A new dimensional constant which characterizes one act of interaction is introduced and estimated. Non-forehead collisions with gravitons will lead to a very specific additional relaxation of any photonic flux. It gives a possibility of another interpretation of supernovae 1a data - without any kinematics. Of course, all of these facts may implicate a necessity to change the standard cosmological paradigm. Some features of a new paradigm are discussed here, too. A quantum mechanism of classical gravity based on an existence of this sea of gravitons is described for the Newtonian limit. This mechanism needs graviton pairing and "an atomic structure" of matter for working it, and leads to the time asymmetry. If the considered quantum mechanism of classical gravity is realized in the nature, than an existence of black holes contradicts to Einstein's equivalence principle. It is shown that in this approach the two fundamental constants - Hubble's and Newton's ones - should be connected between themselves. The theoretical value of the Hubble constant is computed. In this approach, every massive body would be decelerated due to collisions with gravitons that may be connected with the Pioneer 10 anomaly. It is shown that the predicted and observed values of deceleration are in good agreement. Some unsolved problems are discussed, so as possibilities to verify some conjectures in laser-based experiments.
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.
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.
1458405
Low-energy quantum gravity: new challenges for an experiment and observation
Some new challenges for an experiment and observation, which are consequences of the model of low-energy quantum gravity by the author, are considered here. In particular, the property of asymptotic freedom of this model leads to the unexpected consequence: if a black hole arises due to a collapse of a matter with some characteristic mass of particles, its full mass should be restricted from the bottom. For usual baryonic matter, this limit of mass is of the order $10^{7}M_{\odot}$.
119595470
Discrete Symmetries Underlying Some Continuous Ones: Two Examples From Gravity And Particle Physics
Two examples, not connected at present, from author's papers (Nuovo Cim., 1992, v.105A, p.77 [hep-th/0207210] and GRG, 1999, v.31, p.1431 [gr-qc/0207017]) are considered here in which a physical model has discrete symmetries and additional non-observable coordinates or parameters. Then it is possible to introduce some apparent continuous symmetries of the model for an observer which cannot know values of these additional quantities.