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ПУБЛИКАЦИИ ЛАБОРАТОРИИ
ФИЗИКИ ФУНДАМЕНТАЛЬНЫХ ВЗАИМОДЕЙСТВИЙ НИИ ФИЗИКИ ЮФУ
1. G. Vereshkov, N. Volchanskiy.
GAUGE- AND POINT-INVARIANT VERTICLES OF NUCLEON-TO-RESONANCE
INTERACTIONS. // Physical Review C 87, 035203 (2013).
We construct interactions of nucleons N with higher-spin resonances R invariant under point and
gauge transformations of the Rarita-Schwinger field. It is found for arbitrarily high spin of a
resonance that the requirement of point- and gauge-invariance uniquely determines a Lagrangian
of NR interactions with pions, photons, and vector mesons, which might reduce model ambiguity
in effective-field calculations involving such vertices. Considering the NR interactions with
photons and vector mesons, the symmetry provides a classification of three NR vertices in terms
of their differential order. The Q2 dependencies of the point and gauge invariant form factors are
considered in a vector-meson-dominance model. The model is in good agreement with
experimental data. In addition, we point out some empirical patterns in the Q2 dependencies of
the form factors: low- Q2scaling of the N-Delta(1232) form factor ratios and relations between
form factors for N-N(1520) and N-N(1680) transitions.
Ссылка на полный текст статьи: DOI: 10.1103/PhysRevC.87.035203
http://arxiv.org/pdf/1303.4983v1.pdf
2. R. Pasechnik, V. Beilin, G. Vereshkov.
DARK ENERGY FROM GRAVITON-MEDIATED INTERACTIONS IN THE QCD
VACUUM // Journal of Cosmology and Astroparticle Physics, 1306 (2013) 011.
Adopting the hypothesis about the exact cancellation of vacuum condensates contributions to the
ground state energy in particle physics to the leading order in graviton-mediated interactions, we
argue that the observable cosmological constant can be dynamically induced by an
uncompensated quantum gravity correction to them after the QCD phase transition epoch. To
start with, we demonstrate a possible cancellation of the quark-gluon condensate contribution to
the total vacuum energy density of the Universe at temperatures $T<100$ MeV without taking
into account the graviton-mediated effects. In order to incorporate the latter, we then calculate the
leading-order quantum correction to the classical Einstein equations due to metric fluctuations
induced by the non-perturbative vacuum fluctuations of the gluon and quark fields in the
quasiclassical approximation. It has been demonstrated that such a correction to the vacuum
energy density has a form $\varepsilon_{\Lambda}\sim G \Lambda_{\rm QCD}^6$, where $G$
is the gravitational constant, and $\Lambda_{\rm QCD}$ is the QCD scale parameter. We
analyze capabilities of this approach based on the synthesis between quantum gravity in
quasiclassical approximation and theory of non-perturbative QCD vacuum for quantitative
explanation of the observed Dark Energy density.
Ссылка на полный текст статьи:
DOI:
http://arxiv.org/pdf/1302.6456v3.pdf
10.1088/1475-7516/2013/06/011
3. G. Vereshkov, L. Marochnik.
QUANTUM GRAVITY IN HEISENBERG REPRESENTATION AND SELFCONSISTENT THEORY OF GRAVITON IN MACROSCOPIC SPACETIME //
Journal of Modern Physics, 4, 285-297 (2013).
The first mathematically consistent exact equations of quantum gravity in the
Heisenberg representation and Hamilton gauge are obtained. It is shown that the path
integral over the canonical variables in the Hamilton gauge is mathematically equivalent
to the operator equations of quantum theory of gravity with canonical rules of
quantization of the gravitational and ghost fields. In its operator formulation, the theory
can be used to calculate the graviton S-matrix as well as to describe the quantum
evolution of macroscopic system of gravitons in the non-stationary Universe or in the
vicinity of relativistic objects. In the S-matrix case, the standard results are obtained.
For problems of the second type, the original Heisenberg equations of quantum gravity
are converted to a self-consistent system of equations for the metric of the macroscopic
spacetime and Heisenberg operators of quantum fields. It is shown that conditions of the
compatibility and internal consistency of this system of equations are performed without
restrictions on the amplitude and wavelength of gravitons and ghosts. The status of
ghost fields in the various formulations of quantum theory of gravity is discussed.
Ссылка на полный текст статьи: http://arxiv.org/pdf/1108.4256v2.pdf
DOI: 10.4236/jmp.2013.42039
4. V. Kuksa, N. Volchanskiy,
FACTORIZATION IN THE MODEL OF UNSTABLE PARTICLES WITH
CONTINUOUS MASSES // European Journal of Physics C, 11, 182-194 (2013).
We study processes with unstable particles in intermediate time-like states. It is shown that the
amplitudes squared of such processes factor exactly in the framework of the model of unstable
particles with continuous masses. Decay widths and cross sections can then be represented in a
universal factorized form for an arbitrary set of interacting particles. This exact factorization is
caused by specific structure of propagators in the model. We formulate the factorization method
and perform a phenomenological analysis of the factorization effects. The factorization method
considerably simplifies calculations while leading to compact and reasonable results.
Ссылка на полный текст статьи: http://arxiv.org/pdf/1112.2387v2.pdf
DOI: 10.2478/s11534-012-0155-3
5. V. Kuksa, R. Pasechnik, D. Vlasenko.
MASS SHELL SMEARING EFFECTS IN TOP PAIR PRODUCTION //
International Journal of Modern Physics A27, (2012) 1250072.
The top quark pair production and decay are considered in the framework of the smearedmass unstable particles model. The results for total and differential cross sections in
vicinity of $t\bar{t}$ threshold are in good agreement with the previous ones in the
literature. The strategy of calculations of the higher order corrections in the framework of
the model is discussed. Suggested approach significantly simplifies calculations
compared to the standard perturbative one and can serve as a convenient tool for fast and
precise preliminary analysis of processes involving intermediate time-like top quark
exchanges in the near-threshold region.
Ссылка на полный текст статьи: DOI: 10.1142/S0217751X12500728
http://arxiv.org/pdf/1112.2387v2.pdf
6. Yu.F. Novoseltsev, R.V. Novoseltseva and G.M. Vereshkov.
ON THE MASS COMPOSITION OF PRIMARY COSMIC RAYS IN THE ENERGY
REGION 1015 – 1016 eV // Journal of Physics G: Nuclear and Particle Physics, 39 (2012)
105202.
A method to determine the primary cosmic ray mass composition is presented. Data processing is
based on the theoretical model representing the integral muon multiplicity spectrum as the
superposition of the spectra corresponding to different kinds of primary nuclei. The method
consists of two stages. In the first stage, the permissible intervals of primary nuclei fractions fi are
determined on the basis of the EAS spectrum versus the total number of muons (Eμ ≥ 235 GeV).
In the second stage, the permissible intervals of fi are narrowed by the fitting procedure. We use
the experimental data on high multiplicity muon events (nμ ≥ 114) collected at the Baksan
underground scintillation telescope. Within the framework of three components (protons, helium
and heavy nuclei), the mass composition in the region 1015–1016 eV has been defined: fp = 0.235 ±
0.02, fHe = 0.290 ± 0.02, fH = 0.475 ± 0.03. The average logarithmic mass is lnA 1.93 and it is
in good agreement with results before the knee energy obtained by JACEE, RUNJOB, ATIC. At
energies above the knee (1015–1016 eV) our analysis supports KASCADE results and contradicts
to CASA-BLANCA and DICE data.
Ссылка на полный текст статьи:
doi:10.1088/0954-3899/39/10/105202
http://arxiv.org/pdf/1108.4245v2.pdf
7. Yu.F. Novoseltsev, R.V. Novoseltseva and G.M. Vereshkov.
ON THE MASS COMPOSITION OF PRIMARY COSMIC RAYS IN THE ENERGY
REGION 1015 – 1016 eV // Journal of Physics : Conference Series, v.375 (2012) 052015.
The method of the determination of Primary Cosmic Ray mass composition is presented. Data
processing is based on the theoretical model representing the EAS spectrum vs the total number
of muons as the superposition of the spectra corresponding to different kinds of primary nuclei.
The method consists of two stages. At the first stage, the permissible intervals of primary nuclei
fractions fi are determined on the base of the EAS spectrum vs the total number of muons (Eμ ≥
235 GeV). At the second stage, the permissible intervals of fi are narrowed by fitting procedure.
Within the framework of three components (protons, helium and heavy nuclei), the mass
composition in the region 1015 – 1016 eV has been defined: fp = 0.235 ± 0.02, fHe = 0.290 ± 0.02,
fH = 0.475 ± 0.03.
Ссылка на полный текст статьи: doi:10.1088/1742-6596/375/1/052015
Статьи, принятые к публикации во второй половине 2013 года
8. R. Pasechnik, V. Beilin, G. Vereshkov.
ON A POSSIBLE COMPENSATION OF THE QCD VACUUM CONTRIBUTION TO
THE DARK ENERGY // // Physical Review D (2013).
We suggest one of the possible ways to compensate the large negative quantum-topological QCD
contribution to the vacuum energy density of the Universe by means of a positive constant
contribution from a cosmological Yang-Mills field. An important role of the exact particular
solution for the Yang-Mills field corresponding to the finite-time instantons is discussed. An
interesting connection of the compensation mechanism to the color confinement in the framework
of instanton models has been pointed out. Besides the $\Lambda_{\rm QCD}$ scale, this
proposal relies on one yet free dimensionless normalisation constant which cannot be fixed by the
perturbative QCD theory, and thus should be fine-tuned for the exact compensation to hold.
Ссылка на полный текст статьи: http://arxiv.org/pdf/1302.5934v2.pdf
9. L. Marochnik, D. Usikov, G. Vereshkov.
MACROSCOPIC EFFECT OF QUANTUM GRAVITY: GRAVITON, GHOST
AND INSTANTON CONDENSATION ON HORIZON SCALE OF THE
UNIVERSE // Journal of Modern Physics, 8, (2013).
We discuss a special class of quantum gravity phenomena that occur on the scale of the
Universe as a whole at any stage of its evolution. These phenomena are a direct
consequence of the zero rest mass of gravitons, conformal non-invariance of the graviton
field, and one-loop finiteness of quantum gravity. The effects are due to graviton-ghost
condensates arising from the interference of quantum coherent states. Each of coherent
states is a state of gravitons and ghosts of a wavelength of the order of the horizon scale
and of different occupation numbers. The state vector of the Universe is a coherent
superposition of vectors of different occupation numbers. To substantiate the reliability of
macroscopic quantum effects, the formalism of one-loop quantum gravity is discussed in
detail. The theory is constructed as follows: Faddeev-Popov path integral in Hamilton
gauge -> factorization of classical and quantum variables, allowing the existence of a selfconsistent system of equations for gravitons, ghosts and macroscopic geometry ->
transition to the one-loop approximation. The ghost sector corresponding to the Hamilton
gauge ensures of one-loop finiteness of the theory off the mass shell. The BogolyubovBorn-Green-Kirckwood-Yvon (BBGKY) chain for the spectral function of gravitons
renormalized by ghosts is used to build a self-consistent theory of gravitons in the
isotropic Universe. We found three exact solutions of the equations, consisting of BBGKY
chain and macroscopic Einstein's equations. The solutions describe virtual graviton, ghost,
and instanton condensates and are reproduced at the level of exact solutions for field
operators and state vectors. Each exact solution corresponds to a certain phase state of
graviton-ghost substratum. We establish conditions under which a continuous quantumgravity phase transitions occur between different phases of the graviton-ghost condensate.
Ссылка на полный текст статьи: http://arxiv.org/pdf/1306.6172v1.pdf