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E. Bartos

Publications and source records attributed to E. Bartos.

At least 19 recordsLinked to original sources
arXiv2016

Numerical values of $f^F$, $f^D$, $f^S$ coupling constants in $SU(3)$ invariant interaction Lagrangian of vector-meson nonet with $1/2^+$ octet baryons

It is demonstrated how an utilization of all existing experimental information on electric and magnetic nucleon form factors, to be described by the Unitary and Analytic (U\&A) nucleon electromagnetic structure model in space-like and time-like regions simultaneously, can provide numerical values of $f^F$, $f^D$, $f^S$ coupling constants in $SU(3)$ invariant interaction Lagrangian of the vector-meson nonet with $1/2^+$ octet baryons. The latter, together with universal vector-meson coupling constants $f_V$, play an essential role in a prediction of $1/2^+$ octet hyperon electromagnetic form factors behaviors.

hep-ph↗
arXiv2009

Parameter differences of the charged and neutral rho-meson family

New very precise KLOE data on $\m{e}^+\m{e}^-\toπ^+π^-$ obtained by radiative return method in Frascati are unified with corrected CMD-2 and SND Novosibirsk $\m{e}^+\m{e}^-\toπ^+π^-$ data and supplemented below and beyond by older data in order to be described by the unitary and analytic pion electromagnetic form factor model, which provides the most precise neutral $ρ$-meson family parameters. Then the recently appeared accurate Belle (KEK) data of the weak pion form factor are described by the same unitary and analytic model, as it follows from the CVC hypothesis, providing the charged $ρ$-meson family parameters. As a result the most reliable parameter differences of the $ρ$-meson family are determined.

hep-ph↗
arXiv2009

Remarkable suppression of the $e^{+}e^{-}\toπ^{+}π^{-}$ contribution error into muon $g-2$

We use the unitary and analytic model of the pion electromagnetic form factor in order to evaluate in the lowest order the $e^{+}e^{-}\toπ^{+}π^{-}$ contribution into the muon magnetic anomaly. We demonstrate, that this technique enables us to reduce the uncertainty of the theoretical prediction importantly in comparison to usual approaches, where the measured data are integrated directly.

hep-ph↗
arXiv2008

$2γ$ and $3γ$ annihilation as calibration processes for high energy $e^+ e^-$ colliders

Born differential cross sections and the lowest-order radiative correction to them are obtained in the kinematics of large-angle final photons emission in high-energy electron-positron annihilation processes. Taking into account possible emission of real soft and hard photons in collinear kinematics we show the validity of the Drell-Yan form of differential cross section with the nonsinglet structure functions of initial leptons. The leading and next-to leading contribution to the cross sections is obtained. The relevant numerical estimations are presented.

hep-ph↗
arXiv2007

The decay ϕ-> f_0(980) γand the process e^+e^- -> ϕf_0(980)

The decay ϕ-> f_0(980) γand process e^+e^- -> ϕf_0(980) are considered within the local Nambu-Jona-Lasinio model. In the amplitudes of these processes contributions of s-quark and kaon loops are taken into account. The kaon loop gives a dominant contribution. Our estimation for the decay width of ϕ-> f_0 γis in satisfactory agreement with recent experimental data. This allows us to make some predictions for cross sections of the process e^+e^- -> γ^* -> ϕf_0 which can be tested in the C-τfactory. The total and differential cross sections of this process are calculated and presented in the figures.

hep-ph↗
arXiv2007

Sum Rules for Total Cross-Sections of Hadron Photo-Production on Pseudoscalar Mesons and Octet Baryons

Considering very high energy peripheral electron-hadron scattering with a production of hadronic state X moving closely to the direction of initial hadron the Weizsäcker-Williams like expression, relating the difference of q^2-dependent differential cross-sections of DIS processes to the convergent integral over the difference of the total hadron photo-production cross-sections on hadros, is derived. Then, exploiting analytic properties of the forward retarded Compton scattering amplitude on the same hadrons, first, the sum rules are derived bringing into relation hadron electromagnetic form factors with the difference of the q^2-dependent differential cross-sections of DIS, then using Weizsäcker-Williams like expression and taking the derivative of both sides according to ${\bf q^2}$ for ${\bf q^2} \to 0$ one comes to new universal hadron sum rules relating hadron static parameters to the convergent integral over the difference of the total hadron photo-production cross-sections on hadrons.

hep-ph↗
arXiv2007

Sum rule for photon target

The amplitude of zero angle scattering of electron on photon in the 3-rd QED order of fine structure constant with $γ^*γ$ intermediate state converting into quark--antiquark is considered. Utilizing analytic properties of elastic photon--photon scattering amplitude an explicit expression for differential cross- section of quark--antiquark pair production at electron-photon collision in peripheral kinematics is derived apparently. Limiting case of small transferred momenta with an application of the Weizsäcker-Williams like relation gives the sum rule for photon target, bringing into the relation the sum of ratios of the four power of the quark charges to squared quark masses with integral over the total $γγ\to 2 jets$ cross--section.

hep-ph↗
arXiv2007

QED processes in peripheral kinematics at polarized photon-photon and photon-electron colliders

The calibration QED process cross sections for experiments on planned electron-photon and photon-photon colliders for detecting the small angles scattered particles are calculated. These processes describe the creation of two jets moving sufficiently close to the beam axis directions. The jets containing two and three particles including charged leptons, photons and pseudoscalar mesons are considered explicitly. Considering the pair production subprocesses we take into account both bremsstrahlung and double photon mechanisms. The obtained results are suitable for further numerical calculations.

hep-ph↗
arXiv2006

Recoil proton distribution in high energy photoproduction processes

For high energy linearly polarized photon--proton scattering we have calculated the azimuthal and polar angle distributions in inclusive on recoil proton experimental setup. We have taken into account the production of lepton and pseudoscalar meson charged pairs. The typical values of cross sections are of order of hundreds of picobarn. The size of polarization effects are of order of several percents. The results are generalized for the case of electroproduction processes on the proton at rest and for high energy proton production process on resting proton.

hep-ph↗
arXiv2006

Radiative corrections to chiral amplitudes in quasiperipheral kinematics

Chiral amplitudes for two jets processes in quasi-peripheral kinematics are calculated at the Born and one loop correction level. The amplitudes of subprocesses describing interaction of virtual and real photon with creation of a charged fermion pair for various chiral states are considered in details. Similar results are presented for Compton subprocess with virtual photon. Contribution of emission of virtual, soft, and hard real additional photons are taken into account explicitly. The relevant cross sections expressed in terms of impact factors are in agreement with structure function approach in the leading logarithmical approximation. Contributions of the next to leading terms are presented in an analytical form. Accuracy estimation is discussed.

hep-ph↗
arXiv2005

Sum rule for a difference of proton and neutron total photoproduction cross-sections

Starting from very high energy inelastic electron-nucleon scattering with a production of a hadronic state $X$ to be moved closely to the direction of the initial nucleon, then utilizing analytic properties of parts of forward virtual Compton scattering amplitudes on proton and neutron, one obtains the relation between nucleon form factors and a difference of proton and neutron differential electroproduction cross-sections. In particular, for the case of small transferred momenta, one finally derives sum rule, relating Dirac proton mean square radius and anomalous magnetic moments of proton and neutron to the integral over a difference of the total proton and neutron photoproduction cross-sections.

hep-ph↗
arXiv2004

Multiple exchanges in lepton pair production in high--energy heavy ion collisions

The recent analysis of nuclear distortions in DIS off nuclei revealed a breaking of the conventional hard factorization for multijet observable. The related pQCD analysis of distortion effects for jet production in nucleus-nucleus collisions is as yet lacking. As a testing ground for such an analysis we consider the Abelian problem of higher order Coulomb distortions of the spectrum of lepton pairs produced in peripheral nuclear collisions. We report an explicit calculation of the contribution to the lepton pair production in the collision of two photons from one nucleus with two photons from the other nucleus, $2γ+ 2γ\to \m{l}^+\m{l}^-$. The dependence of this amplitude on the transverse momenta has a highly nontrivial form the origin of which can be traced to the mismatch of the conservation of the Sudakov components for the momentum of leptons in the Coulomb field of the oppositely moving nuclei. The result suggests that the familiar eikonalization of Coulomb distortions breaks down for the oppositely moving Coulomb centers, which is bad news from the point of view of extensions to the pQCD treatment of jet production in nuclear collisions. On the other hand, we notice that the amplitude for the $2γ+ 2γ\to \m{l}^+\m{l}^-$ process has a logarithmic enhancement for the lepton pairs with large transverse momentum, which is absent for $nγ+ mγ\to \m{l}^+\m{l}^-$ processes with $m,n > 2$. We discuss the general structure of multiple exchanges and show how to deal with higher order terms which cannot be eikonalized.

hep-ph↗
arXiv2004

Double-logarithmic behavior of inelastic fermion form factors in QED and QCD

The effective kinematic diagram technique is applied to study inelastic form factors of electron and quark in QED and QCD. The explicit expressions for these form factors in the double-logarithmic approximation are presented. The self-consistency of the results is shown by demonstrating the fulfillment of the Kinoshita-Lee-Nauenberg theorem.

hep-ph↗
arXiv2003

Radiative muon (pion) pair production in high energy electron-positron annihilation (the case of small invariant pair mass)

The process of the muon (pion) pair production with small invariant mass in the electron--positron high--energy annihilation, accompanied by emission of hard photon at large angles, is considered. We find that the Drell--Yan picture for differential cross section is valid in the charge--even experimental set--up. Radiative corrections both for electron block and for final state block are taken into account.

hep-ph↗
arXiv2003

The lowest order inelastic QED processes at polarized photon-electron high energy collisions

The compact expressions for cross sections of photoproduction of a pair of charged particles $\mathrm{e}^+,\mathrm{e}^-$; $μ^+,μ^-$; $π^+,π^-$ as well as the double Compton scattering process are given. The explicit analytic expressions for the case of polarized photon and the initial electron in the kinematics when all the particles can be considered as a massless ones are presented. The photon polarization is described in the terms of Stokes parameters.

hep-ph↗