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I. M. Narodetskii

Publications and source records attributed to I. M. Narodetskii.

At least 19 recordsLinked to original sources
arXiv2014

Magnetic Moments of Negative Parity Baryons from Effective Hamiltonian Approach to QCD

Magnetic moments of $S_{11}(1535)$ and $S_{11}(1650)$ baryons are studied in the framework of the relativistic three-quark Hamiltonian derived in the Field Correlation Method. The baryon magnetic moments are expressed via the average current quark energies which are defined by the fundamental QCD parameters: the string tension $σ$, the quark masses, and the strong coupling constant $α_s$. For the $J^P=1/2^+$ baryon octet the approach was shown to give a good first approximation to the experimental moments. Resulting magnetic moments for the $J^P=1/2^-$ nucleons are compared both to model calculations and to those from lattice QCD.

hep-ph↗
arXiv2011

String Correction for Baryon Orbital Excitations

The correction to the string junction three-quark potential in a baryon due to the proper moment of inertia of the QCD string is calculated. The magnitudes of the string corrections in P-wave heavy baryons are estimated.

hep-ph↗
arXiv2010

J/ψand Upsilon at high temperature

We use the screened Coulomb potential with $r$-dependent coupling constant and the non--perturbative quark--antiquark potential derived within Field Correlator Method (FCM) to calculate $J/ψ$ and $Υ$ binding energies and melting temperatures in the deconfined phase of quark-gluon plasma.

hep-ph↗
arXiv2009

Diquark and triquark correlations in the deconfined phase of QCD

We use the non-perturbative Q\bar Q potential at finite temperatures derived in the Field Correlator Method to obtain binding energies for the lowest eigenstates in the Q\bar Q and QQQ systems (Q=c,b). The three--quark problem is solved by the hyperspherical method. The solution provides an estimate of the melting temperature and the radii for the different diquark and triquark bound states. In particular we find that J/ψand $ccc$ ground states survive up to T \sim 1.3 T_c, where T_c is the critical temperature, while the corresponding bottomonium states survive even up to higher temperature, T \sim 2.2 T_c.

hep-ph↗
arXiv2009

Baryons in the Field Correlator Method

The ground and $P$-wave excited states of $nnn$, $nns$ and $ssn$ baryons are studied in the framework of the field correlator method using the running strong coupling constant in the Coulomb-like part of the three-quark potential. The string correction for the confinement potential of the orbitally excited baryons, which is the leading contribution of the proper inertia of the rotating strings, is estimated.

hep-ph↗
arXiv2009

Baryons in the Field Correlator Method: Effects of the Running Strong Coupling

The ground and P-wave excited states of nnn, nns and ssn baryons are studied in the framework of the Field Correlator Method using the running strong coupling constant in the Coulomb-like part of the three-quark potential. The running coupling is calculated up to two loops in the background perturbation theory. The three-quark problem has been solved using the hyperspherical functions method. The masses of the S- and P-wave baryons are presented. Our approach reproduces and improves the previous results for the baryon masses obtained for the freezing value of the coupling constant. The string correction for the confinement potential of the orbitally excited baryons, which is the leading contribution of the proper inertia of the rotating strings, is estimated.

hep-ph↗
arXiv2008

Accuracy of Auxiliary Field Approach for Baryons

We provide a check of the accuracy of the auxiliary field formalism used to derive the Effective Hamiltonian for baryons in the Field Correlator Method. To this end we compare the solutions for the Effective Hamiltonian with those obtained from the solution of the Salpeter equation. Comparing these results gives a first estimate of the systematic uncertainty due to the use of the auxiliary field formalism for baryons.

hep-ph↗
arXiv2008

Heavy baryon spectroscopy in the QCD string model

QCD string model formulated in the framework of the Field Correlator Method (FCM) in QCD is employed to calculate the masses of $Σ_c$, $Ξ_c$ and recently observed at Tevatron $Σ_b$, $Ξ_b$ baryons and their orbital excitations. The auxiliary field formalism allows one to write a simple local form of the effective Hamiltonian for the three quark system, which comprises both confinement and relativistic effects, and contains only universal parameters: the string tension $σ$, the strong coupling constant $α_s$, and the bare (current) quark masses $m_i$. We calculate the hyperfine splitting with account of the both perturbative and non--perturbative spin-spin forces between quarks in a baryon. For the orbital excitations we estimate the string correction for the confinement potential - the leading correction to the contribution of the proper inertia of the rotating string. This correction lowers the masses of the P-states by 50 MeV. We find our numerical results to be in good agreement with experimental data.

hep-ph↗
arXiv2007

P Wave Baryons in Field Correlator Method: Hyperons

We provide an investigation of the P-wave hyperons employing the field correlator method in QCD. This method allows to derive the Effective Hamiltonian successfully applied to the meson and ground state baryon spectra. The hyperon spectrum appears to be expressed through two parameters relevant to QCD, the string tension σ, the strong coupling constant α_s, and the bare strange quark mass m_s. Using these parameters a unified description of the ground and excited hyperon states is achieved. We also briefly consider the nucleon P-wave excitations. In particular, we predict that both the nucleon and hyperon states have the similar cost (in ΔL) ~460 MeV.

hep-ph↗
arXiv2006

Inclusive pentaquark and strange baryons production in hadron beam experiments at high energy

We estimate the high-energy behavior of the $Θ^+$ and $Λ(1520)$ production cross sections in inclusive $pp$ collisions using the $K$ exchange diagram. We show that the cross section of the $Θ^+$-production is suppressed compared to the production of $Λ(1520)$. As a byproduct we also estimate the contribution of the $π$ exchange diagram for the inclusive $Λ(1520)$ production in $Σp$ collisions.

hep-ph↗
arXiv2006

Inclusive pentaquark and strange baryons production in pp and Σp collisions at high energy

We calculate the cross sections for the inclusive production in the fragmentation region of $Θ^+(1540)$ and $Λ(1520)$ in $pp$ collisions and $Λ(1520)$ in $Σp$ collisions at high energy using the $K$- and $π$-meson exchange diagrams, respectively. The contributions of these diagrams survive at asymptotically large energies and are energy independent in this region up to logarithmic and power corrections. We find that inclusive $Θ^+(1540)$ production should be at the level of 1 $μ\mathrm{b}\timesΓ_{ΘKN}/ 1$ MeV. The ratio of the $Θ^+(1540)$ over the $Λ(1520)$ yields is found to be $\sim 1%$. The fraction of $Λ(1520)$ yields in $Σp$ and $pp$ collisions is $\sim 2.7$ that quantitatively agrees with the preliminary result of the Fermilab fixed target experiment E781.

hep-ph↗
arXiv2006

Θ^+ and Λ(1520) production in pp reactions at high energies

We estimate the cross sections for the inclusive production of $Θ^+$ and $Λ(1520)$ in $pp$ collisions at high energy using the $K$ exchange diagrams. We find that inclusive $Θ^+$ production should be at the level of 1 $μ$b at energies~ $\sqrt{s}~\gtrsim~10~{\rm GeV}$. The ratio of $Θ^+(1540)$ to $Λ(1520)$ production cross-sections is $\sim 1%$.

hep-ph↗
arXiv2005

Pentaquarks in the Jaffe-Wilczek approximation

The masses of $uudd\bar s $, $uudd\bar d$ and $uuss\bar d$ pentaquarks are evaluated in a framework of both the Effective Hamiltonian approach to QCD and spinless Salpeter using the Jaffe--Wilczek diquark approximation and the string interaction for the diquark--diquark--antiquark system. The pentaquark masses are found to be in the region above 2 GeV. That indicates that the Goldstone boson exchange effects may play an important role in the light pentaquarks. The same calculations yield the mass of $[ud]^2\bar c$ pentaquark $\sim$ 3250 MeV and $[ud]^2\bar b$ pentaquark $\sim$ 6509 MeV.

hep-ph↗
arXiv2004

Pentaquarks in string dynamics

The masses of $uudd\bar s $, $uudd\bar d$, and $uuss\bar d$ pentaquarks are evaluated in a framework of both the Effective Hamiltonian approach to QCD and spinless Salpeter using the Jaffe-Wilczek diquark approximation and the string interaction for the diquark-diquark-antiquark system. The masses of the light pentaquarks are found to be in the region above 2 GeV. The similar calculations yield the mass of $[ud]^2\bar c$ pentaquark $\sim$ 3250 MeV and $[ud]^2\bar b$ pentaquark $\sim$ 6509 MeV.

hep-ph↗
arXiv2003

Pentaquark spectrum in string dynamics

The masses of $uudd\bar s $ and $uudd\bar d$ pentaquarks are evaluated in a framework of the Effective Hamiltonian approach to QCD using the Jaffe-Wilczek $[ud]^2\bar q$ approximation. The mass of the $[ud]^2\bar s$ state is found to be $\sim 300-500$ MeV higher than the observed $Θ^+(1540)$ mass.

hep-ph↗
arXiv2003

Selected Theoretical Issues in B-meson Physics: CKM matrix and Semileptonic Decays

These notes are a written version of a lecture given at the International Seminar {\it Modern Trends and Classical Approach} devoted to the 80$^{th}$ anniversary of Prof. Karen Ter-Martirosyan, ITEP September 30 -- October 1, 2002. The notes represent a non-technical review of our present knowledge on the phenomenology of weak decays of quarks, and their rôle in the determination of the parameters of the Standard Model. They are meant as an introduction to some of the latest results and applications in the field. Specifically, we focus on CP violation in B-decays and the determination of the CKM matrix element $V_{cb}$ from semileptonic decays of $B$ mesons. We also briefly discuss phenomenological applications concerning the electron-energy spectra in semileptonic $B$ and $B_c$ decays.

hep-ph↗
arXiv2003

Ground-state baryons in nonperturbative quark dynamics

We review the results obtained in an Effective Hamiltonian (EH) approach for the three-quark systems. The EH is derived starting from the Feynman--Schwinger representation for the gauge-invariant Green function of the three quarks propagating in the nonperturbative QCD vacuum and assuming the minimal area law for the asymptotic of the Wilson loop. It furnishes the QCD consistent framework within which to study baryons. The EH has the form of the nonrelativistic three-quark Hamiltonian with the perturbative Coulomb-like and nonperturbative string interactions and the specific mass term. After outlining the approach, methods of calculations of the baryon eigenenergies and some simple applications are explained in details. With only two parameters: the string tension $σ=0.15 GeV^2$ and the strong coupling constant $α_s=0.39$ a unified quantitative description of the ground state light and heavy baryons is achieved. The prediction of masses of the doubly heavy baryons not discovered yet are also given. In particular, a mass of $3660 MeV$ for the lightest $Ξ_{cc}$ baryon is found by employing the hyperspherical formalism to the three quark confining potential with the string junction.

hep-ph↗