arXiv subjects
Publications and source records attributed to M. V. Chizhov.
The inserting of antisymmetric tensor fields into the standard electroweak theory may explain the recent experiments on pi -> e nu gamma and K -> pi e nu decays. New intermediate particles can induce the destructive interference in the pion decay and the nonzero tensor and scalar form factors in the kaon decay.
The preliminary results of PIBETA experiment strongly suggest the presence of non V-A anomalous interactions in the radiative pion decay. We assume that they arise as a result of the exchange of new intermediate chiral spin-1 bosons which interact anomalously with matter. Their contribution into the tau-decay leads to violation of the CVC hypothesis at the same level as detected experimentally.
The preliminary results of PIBETA experiment strongly suggest the presence of non V-A anomalous interactions in the radiative pion decay. Without a guiding idea about the nature of these new interactions it is very difficult to interpret and fit experimental data. We assume that they arise as a result of the exchange of new intermediate chiral bosons which interact anomalously with matter. Their mixing with W-bosons leads effectively to a small anomalous weak moment for W. Based on these assumptions, we show that the most general form of the radiative pion decay rate can be parametrized by three new coupling constants of the anomalous interactions.
A simple explanation of the dynamic properties of vector mesons is given in the framework of extended Nambu - Jona-Lasinio quark model. New mass relations among the hadron vector resonances are derived. The results of this approach are in good accordance with the QCD sum rules, the lattice calculations and the experimental data.
We show that the hadron vector resonances are described by fields transforming according to different inequivalent representations of the Lorentz group: (1/2,1/2) and (1,0)+(0,1). The vector representation (1/2,1/2) is well studied and corresponds to the gauge fields. On the other hand, the chiral representations (1,0) and (0,1) are described by the second rank antisymmetric tensor fields, for which interaction theory has not yet been constructed. In the framework of the phenomenological Nambu - Jona-Lasinio approach we have introduced and used all these fields for a description of the vector resonances. A new mass relation between low-lying hadron vector and axial-vector resonances is obtained. This relation is in agreement with the present experimental data.
All known elementary vector particles, the photon, Z, W and the gluons, are described by the gauge theory. They belong to the real representation (1/2,1/2) of the Lorentz group. On the other hand inequivalent representations (1,0) and (0,1) also correspond to particles with spin 1. It is natural to suppose that, along with the known vector particles, the new particles can exist. Evidence for the existence of these particles in nature is the presence of the axial-vector meson resonances with quantum numbers 1^{+-}. Other indications for their existence are discussed. The signatures of their contributions into different physical processes are presented.
We show that the arguments forming the basis for the claim that the conditions for total neutrino conversion derived and studied in detail in [1,2] ``are just the conditions of the parametric resonance of neutrino oscillations supplemented by the requirement that the parametric enhancement be complete'', given in [4] have flaws which make the claim physically questionable. We show also that in the case of the transitions in the Earth of the Earth-core-crossing solar and atmospheric neutrinos the peaks in the relevant transitions probabilities $P_{a b}$, associated with the new conditions, $max P_{a b} = 1$, are of physical relevance - in contrast to what is suggested in [4]. Actually, the enhancement of $P_{a b}$ in any region of the corresponding parameter space are essentially determined by these absolute maxima of $P_{a b}$. We comment on few other aspects of the results derived in [1,2,3] which have been misunderstood and/or misinterpreted in [4].
The neutrino oscillation enhancement in the Earth-type medium mantle - core - mantle is discussed. It is noted that the total conversion is possible both for a resonant matter density and a nonresonant one. A useful parameterization, for the representation of the transition probability for neutrinos and antineutrinos in a single plot, is proposed.
We have provided a numerical study of the influence of the resonant active-sterile neutrino oscillations between electron and sterile neutrinos, on the primordial production of helium-4. The evolution of the neutrino ensembles was followed selfconsistently with the evolution of the nucleons, using exact kinetic equations for the neutrino density matrix and the nucleon number densities in momentum space, from the time of neutrino decoupling till the freeze-out of nucleons at 0.3 MeV. The exact kinetic approach enabled us to study precisely the neutrino depletion, spectrum distortion and neutrino mixing generated asymmetry due to oscillations at each momentum mode, and to prove that their effect on nucleosynthesis is considerable. We have calculated the dependence of the primordially produced helium-4 Y_p on the oscillation parameters for the full range of mixing parameters of the model of oscillations with small mass differences less than 10^{-7} eV^2. We have obtained iso-helium contours on the oscillation parameters plane. Cosmological constraints on oscillation parameters, more precise than the existing ones, were extracted, due to the exact kinetic approach and the proper account for the neutrino spectrum distortion and the oscillations generated asymmetry.
A new effect of total neutrino conversion is possible when neutrino propagates through multi-layer medium of nonperiodic constant density layers. The effect can take place in the oscillations in the Earth of the Earth-core-crossing solar and atmospheric neutrinos.
In this article we discuss lepton asymmetry effect on BBN with neutrino oscillations. We argue that asymmetry much smaller than 0.01, although not big enough to influence directly the nucleosynthesis kinetics, can effect considerably BBN indirectly via neutrino oscillations. Namely, it distorts neutrino spectrum and changes neutrino density evolution and the pattern of oscillations (either suppressing or enhancing them), which in turn effect the primordial synthesis of elements. We show that the results of the paper X. Shi et al., Phys. Rev. D 60, 063002 (1999), based on the assumption that only L > 0.01 will influence helium-4 production, are not valid. Instead, the precise constraints on neutrino mixing parameters from BBN are presented.
We discuss a mechanism for producing baryon density perturbations during inflationary stage and study the evolution of the baryon charge density distribution in the framework of the low temperature baryogenesis scenario. This mechanism may be important for the large scale structure formation of the Universe and particularly, may be essential for understanding the existence of a characteristic scale of 130h^{-1} Mpc (comoving size) in the distribution of the visible matter. The detailed analysis showed that both the observed very large scale of the visible matter distribution in the Universe and the observed baryon asymmetry value could naturally appear as a result of the evolution of a complex scalar field condensate, formed at the inflationary stage. Moreover, according to our model, the visible part of the Universe at present may consist of baryonic and antibaryonic regions, sufficiently separated, so that annihilation radiation is not observed.
We study the nonresonant oscillations between left-handed electron neutrinos nu_e and nonthermalized sterile neutrinos nu_s in the early Universe plasma. The case when nu_s do not thermalize till 2 MeV and the oscillations become effective after nu_e decoupling is discussed. The evolution of neutrino ensembles was described numerically by integrating the kinetic equations for the neutrino density matrix in momentum space. We have provided a detail numerical study of the influence of the nonequilibrium nu_e - nu_s oscillations on the primordial production of He-4. The exact kinetic approach enabled us to calculate the effects of neutrino population depletion, the distortion of the neutrino energy spectrum and the generation of neutrino-antineutrino asymmetry on the kinetics of neutron-to-proton transitions during the primordial nucleosynthesis epoch and correspondingly on the cosmological He-4 production. It was shown that the neutrino population depletion and spectrum distortion play an important role. The asymmetry effect, in case the lepton asymmetry is accepted initially equal to the baryon one, is proved to be negligible for the discussed range of delta m^2. Constant helium contours in delta m^2 - theta plain were obtained for small mass differences delta m^2 < 10^{-7} eV^2. More precise cosmological constraints on mixing parameters were obtained.
The anomalous value of the tensor form factor in the kaon decay K -> pi e nu and the destructive interference in pion decay pi -> e nu gamma can be simultaneously described by admixture of a tensor interaction in the standard V-A one. It is shown that the same tensor interaction can describe recent HERA data at very large Q^2.
We studied nonequilibrium oscillations between left-handed electron neutrinos and nonthermalized sterile neutrinos. The exact kinetic equations for neutrinos, written in terms of neutrino density matrix in momentum space were analyzed. The evolution of neutrino density matrix was numerically calculated. This allowed to study precisely the evolution of the neutrino number densities, energy spectrum distortion and the asymmetry between neutrinos and antineutrinos for each momentum mode. Both effects of distortion and asymmetry, which cannot be accounted for correctly when working in terms of particle densities and mean energies, and the depletion of electron neutrino state have been proved considerable for a certain range of oscillation parameters. The influence of nonequilibrium oscillations on primordial nucleosynthesis was calculated. Cosmologically excluded regions for oscillation parameters were obtained.
Predictions for the muon decay spectrum are usually derived from the derivative-free Hamiltonian. However, it is not the most general form of the possible interactions. Additional simple terms with derivatives can be introduced. In this work the distortion of the standard energy and angular distribution of the electrons in polarized muon decay caused by these terms is presented.
It is shown that in the one-flavour NJL model the vector and axial-vector quasiparticles described by the antisymmetric tensor field are generated. These excitations have tensor interactions with quarks in contrast to usual vector ones. Phenomenological applications are discussed.
We studied nonequilibrium oscillations between left-handed electron neutrinos and nonthermalized sterile neutrinos in medium for resonant and nonresonant cases. The exact kinetic equations for neutrinos, written in terms of neutrino density matrix in {\it momentum space} were analyzed. The evolution of neutrino density matrix was numerically calculated. This allowed to study precisely the evolution of the neutrino number densities, energy spectrum distortion and the asymmetry between neutrinos and antineutrinos for each momentum mode. The influence of nonequilibrium oscillations on the primordial production of He-4 was calculated. Cosmological constraints on the oscillation parameters were obtained.