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A. V. Kiselev

Publications and source records attributed to A. V. Kiselev.

At least 19 recordsLinked to original sources
arXiv2022

Electroweak production of $χ_{Q1}$ states in $e^+e^-$ collisions: A brief review

A brief review of the available experimental and theoretical results on the production of the $χ_{Q1}$ states in $e^+e^-$ annihilation and photon-photon $γγ^*$ interactions is presented. Future data on the production of the $χ_{c1}(1P)$, $χ_{c1}(3872)$, $χ_{c1} (4140)$, $χ_{c1}(4274)$, $χ_{c1}(4685)$, $χ_{b1} (1P)$, $χ_{b1}(2P )$, and $χ_{b1}(3P)$ resonances in $e^+e^-$ annihilation and $γγ^*$ interactions will help the development and unification of theoretical predictions related to the electroweak decays of heavy quarkonia, the reduction of their spread and model uncertainties.

hep-ph↗
arXiv2021

Generalized Vector Dominance Model up to 2 GeV

The processes $e^+e^-\to π^+π^-, ωπ^0, ηπ^+π^-, K^+K^-, π^+π^-π^0$ are described simultaneously in the frame of the Generalized Vector Dominance Model (GVDM) allowing model error. The data do not contradict the assumption that the precision of the model we use is not worse than 6\%. This shows that GVDM is an adequate approach to describe processes involving $ρ(770),ω(787),ϕ(1020)$ and their excitations in the energy region below 2 GeV. This work is considered as a first step, next steps should treat more processes and take into account finer effects.

hep-ph↗
arXiv2021

Semileptonic decays $D\toηπe^+ν_e$ in the $a_0(980)$ region

The mechanism of the four-quark production of the light scalar isovector four-quark state $a_0(980)$ in the $D\toηπe^+ν_e$ decays is discussed. It is shown that the characteristic features of the shape of the $ηπ$ mass spectra expected in our scheme can serve as the indicator of the production mechanism and internal structure of the $a_0(980)$ resonance.

hep-ph↗
arXiv2021

Evidence of the four-quark nature of $f_0(980)$ and $f_0(500)$

There exists a great deal of concrete evidence in favor of the exotic four-quark nature of light scalars. At the same time, the further expansion of the area of the $q^2\bar q^2$ model validity for light scalars on ever new processes seems extremely interesting and important. We analyze the BESIII data on the decay $J/ψ\to γπ^0π^0$ and show that the results of this high-statistics experiment can be interpreted in favor of the four-quark nature of light scalar mesons $f_0(980)$ and $f_0(500)$.

hep-ph↗
arXiv2020

Semileptonic decays $D\toπ^+π^-e^+ν_e$ and $D_s\toπ^+π^-e^+ν_e$ as the probe of constituent quark-antiquark pairs in the light scalar mesons

Decays $D\toπ^+π^-e^+ν_e$ and $D_s\toπ^+ π^-e^+ν_e$ serve as probes that check the existence of constituent $q\bar q$ components in the wave functions of scalar mesons decaying into $π^+π^-$. There exists a great deal of concrete evidence in favor of the exotic four-quark nature of light scalars. At the same time, the further expansion of the area of the $q^2\bar q^2$ model validity for light scalars on ever new processes seems extremely interesting and important. We analyze the BESIII and CLEO data on the decays $D^+\to π^+π^- e^+ν_e$ and $D^+_s\to π^+π^- e^+ν_e$ and show that the results of these experiments together can be interpreted in favor of the four-quark nature of light scalar mesons $σ(500)$ and $f_0(980)$. Our approach can also be applied to the description of other similar decays involving light scalars.

hep-ph↗
arXiv2018

The $a_0(980)$ physics in semileptonic $D^0$ and $D^+$ decays

The decays $D^0\to d\bar u\,e^+ν\to a^-_0(980)\, e^+ν\toπ^-η\, e^+ν$ and $D^+\to d\bar d\,e^+ν\to a^0_0(980)\, e^+ν\toπ^0η\, e^+ν$ (and the charge conjugated ones) is the direct probe of the two-quark components in the $a^\pm_0(980)$ and $a^0_0(980)$ wave functions. Recent BESIII experiment is the first step in experimental study of these decays. We present a possible variant of $ηπ$ invariant mass distribution when $a_0(980)$ has no $q\bar q$ component at all.

hep-ph↗
arXiv2018

Light scalar mesons and two-kaon correlation functions

It is shown that the recent data on the $K^0_S K^+$ correlation in Pb-Pb interactions agree with the data on the $γγ\toηπ^0$ and $ϕ\toηπ^0γ$ reactions and support the four-quark model of the $a_0(980)$ meson. It is shown that the data does not contradict the validity of the Gaussian assumption. The study of two-kaon correlations could provide more information about light scalar mesons after increasing the accuracy of the experimental and theoretical descriptions.

hep-ph↗
arXiv2016

Comparative study of the scalar- and tensor-meson production in the reaction $γγ^*(Q^2)\to ηπ^0$

The prediction of the cross section $σ(γγ^*(Q^2)\to ηπ^0)$ based on the simultaneous description of the Belle data on the $γγ\to ηπ^0$ reaction and the KLOE data on the $ϕ\toηπ^0γ$ decay is presented. The production of the scalar $a_0(980)$ and tensor $a_2(1320)$ is studied in detail. It is shown that the QCD based asymptotics of the $γ^*(Q^2)γ\to a_2(1320)\toηπ^0$ cross section can be reached by the compensation of the contributions of $ρ(770)$ and $ω(782)$ with the contributions of their radial excitations in $Q^2$ channel. At large $Q^2$ the $a_2(1320)$ contribution is expected to be dominant, while at $Q^2=0$ it is similar to the scalars contribution.

hep-ph↗
arXiv2016

Transition form factors $γ^*\to γf_2(1270)$ and $γ^*\to γa_2(1320)$ in the $e^+e^-$ collisions

The predictions for transition form factors $γ^*\to γf_2(1270)$ and $γ^*\to γa_2(1320)$ and corresponding $e^+e^-\to γ^*\to f_2γ$ and $e^+e^-\to γ^*\to a_2γ$ cross sections are obtained for the energy region up to $2$ GeV. These predictions are coordinated with the recent Belle data on the $γ^*(Q^2)γ\to f_2$ transition. It is shown that the QCD asymptotics of the amplitudes of the reactions $e^+e^-\to γ^*\to f_2γ$ and $e^+e^-\to γ^*\to a_2γ$ can be reached only by taking into account a compensation of contributions of $ρ(770)$, $ω(782)$ with contributions of their radial excitations. The relation $σ(e^+e^-\to γ^*\to f_2γ)/σ(e^+e^-\to γ^*\to a_2γ)\approx 25/9$, obtained with the help of the $q\bar q$ model of $a_2$ and $f_2$ and QCD, is used to determine the $σ(e^+e^-\to γ^*\to a_2γ)$ at high energies. Recent BABAR measurement of the $e^+e^-\to f_2γ\toπ^+π^-γ$ cross section at $10.58$ GeV gives hope for detailed investigation of the $γ^*(s)\to f_2γ$ and $γ^*(s)\to a_2γ$ transition form factors at high energy region.

hep-ph↗
arXiv2015

Study of the $f_2(1270)$ and $a_2(1320)$ resonances in $γ^*(Q^2)γ$ collisions

We discuss studies of the $Q^2$ dependence of the $f_2(1270)$ and $a_2 (1320)$ production cross sections in $γ^*(Q^2)γ$ collisions at current and coming into operation colliders with a high luminosity. Changing the dominant helicity amplitude occurs in the reactions $γ^*(Q ^2)γ\to f_2(1270)$ and $γ^*(Q^2) γ\to a_2(1320)$ with increasing $Q^2$. This is caused by the coming of the QCD asymptotics. It is shown that the transition to the asymptotic behavior of QCD in the amplitudes $γ^*(Q^2) γ\to f_2(1270),a_2(1320)$ is provided by the compensation of the contributions of ground vector states $ρ$ and $ω$ in $Q^2$-channel with the contributions of their radial excitations.

hep-ph↗
arXiv2013

Comparative study of the production of scalar and tensor mesons in $e^+e^-$ collisions

The intensity of scalar $a_0(980)$, $f_0(980)$ and tensor $a_2(1320)$, $f_2(1270)$ mesons production at VEPP-2000 (BINP, Novosibirsk) and the upgraded DA$Φ$NE (Frascati, Italy) in the processes $e^+e^- \to a_0 (f_0$, $a_2$, $f_2) γ$ is calculated. The calculation was made with the help of VDM and the kaon loop model (for scalar mesons case). Note that the processes $e^+e^-\to a_2(f_2)γ$ have not been studied in the energy region of VEPP-2000. It turned out that in the VEPP-2000 energy region $1.7-2.0$ GeV $σ(e^+e^-\to a_2(f_2)γ)\sim 10$ pb, and $σ(e^+e^-\to a_0(f_0)γ)\sim 0.1$ pb. Photon angle distribution and the spin density matrices of $a_2$ and $f_2$ were calculated also.

hep-ph↗
arXiv2012

Light scalars in semi-leptonic decays of heavy quarkonia

We study the mechanism of production of the light scalar mesons in the $D_s^+\toπ^+π^- e^+ν$ decays: $D_s^+\to s\bar s e^+ν\to [σ(600)+f_0(980)] e^+ν\toπ^+π^- e^+ν$, and compare it with the mechanism of production of the light pseudoscalar mesons in the $D_s^+\to (η/η') e^+ν$ decays: $D_s^+\to s\bar s e^+ν\to (η/η')e^+ν$. We show that the $s\bar s\toσ(600)$ transition is negligibly small in comparison with the $s\bar s\to f_0(980)$ one. As for the the $f_0(980)$ meson, the intensity of the $s\bar s\to f_0(980)$ transition makes near thirty percent from the intensity of the $s\bar s\toη_s$ ($η_s=s\bar s$) transition. So, the $D_s^+\toπ^+π^- e^+ν$ decay supports the previous conclusions about a dominant role of the four-quark components in the $σ(600)$ and $f_0(980)$ mesons.

hep-ph↗
arXiv2012

Analytical $ππ$ scattering amplitude and the light scalars-II

In the paper Phys. Rev. {\bf D83}, 054008 (2011) we constructed the $ππ$ scattering amplitude $T^0_0$ with regular analytical properties in the $s$ complex plane, describing both experimental data and the results based on chiral expansion and Roy equations. Now the results obtained during development of our work are presented. We dwell on questions dealing with the low $σ-f_0$ mixing, inelasticity description and the kaon loop model for $ϕ\to γ(σ+f_0)$ reaction, and show a number of new fits. In particular, we show that the minimization of the $σ-f_0$ mixing results in the four-quark scenario for light scalars: the $σ$(600) coupling with the $K\bar K$ channel is suppressed relatively to the coupling with the $ππ$ channel, and the $f_0$(980) coupling with the $ππ$ channel is suppressed relatively to the coupling with the $K\bar K$ channel. The correct analytical properties of the $ππ$ scattering amplitude are reached with the help of rather complicated background function. We also suggest much more simple background parameterization, practically preserving the resonance features, which is comfortable for experimental data analysis, but allows to describe the results based on chiral expansion and Roy equations only on the real $s$ axis.

hep-ph↗
arXiv2011

Gardner's deformations of the graded Korteweg-de Vries equations revisited

We solve the Gardner deformation problem for the N=2 supersymmetric a=4 Korteweg-de Vries equation (P. Mathieu, 1988). We show that a known zero-curvature representation for this superequation yields the system of new nonlocal variables such that their derivatives contain the Gardner deformation for the classical KdV equation.

nlin.SI↗
arXiv2011

The analytical $ππ$ scattering amplitude and the light scalars

In this work we construct the $ππ$ scattering amplitude $T^0_0$ with regular analytical properties in the $s$ complex plane, which describes simultaneously the data on the $ππ$ scattering, $ϕ\toπ^0π^0γ$ decay, and $ππ\to K\bar K$ reaction. The chiral shielding of the $σ(600)$ meson and its mixing with the $f_0(980)$ meson are also taken into account. The data agrees with the four-quark nature of the $σ(600)$ and $f_0(980)$ mesons. The amplitude in the range $-5 m_π^2 < s < 0.64$ GeV$^2$ also agrees with results, obtained on the base of the chiral expansion, dispersion relations, and the Roy equations.

hep-ph↗
arXiv2010

Analytical properties of the $ππ$ scattering amplitude and the light scalar mesons

The $ππ$ scattering amplitude with regular analytical properties in the $s$ complex plane has been constructed. It describes simultaneously the data on the $ππ$ scattering, $ϕ\toπ^0π^0γ$ decay and $ππ\to K\bar K$ reaction. The chiral shielding of the $σ(600)$ meson and it's mixing with the $f_0(980)$ meson are taken into account also. The data agrees with the four-quark nature of the $σ(600)$ and $f_0(980)$ mesons. The amplitude in the range $-5 m_π^2 < s < 0.64$ GeV$^2$ also agrees with results, obtained on the base of the chiral expansion, dispersion relations and the Roy equations.

hep-ph↗
arXiv2009

Gardner's deformations of the N=2 supersymmetric a=4-KdV equation

We prove that P.Mathieu's Open problem on constructing Gardner's deformation for the N=2 supersymmetric a=4-Korteweg-de Vries equation has no supersymmetry invariant solutions, whenever it is assumed that they retract to Gardner's deformation of the scalar KdV equation under the component reduction. At the same time, we propose a two-step scheme for the recursive production of the integrals of motion for the N=2, a=4-SKdV. First, we find a new Gardner's deformation of the Kaup-Boussinesq equation, which is contained in the bosonic limit of the super-hierarchy. This yields the recurrence relation between the Hamiltonians of the limit, whence we determine the bosonic super-Hamiltonians of the full N=2, a=4-SKdV hierarchy. Our method is applicable towards the solution of Gardner's deformation problems for other supersymmetric KdV-type systems.

nlin.SI↗