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61.
Yu. A. Simonov 《Physics of Atomic Nuclei》2004,67(5):1027-1034
New spectral representations for f π and chiral condensate are derived in QCD and used for calculations in the large-N c limit. Both quantities are expressed in this limit through string tension σ and gluon correlation length T g without fitting parameters. As a result, one obtains $\left\langle {\bar qq} \right\rangle = - N_c \sigma ^2 T_g a_1 $ , $f_\pi = \sqrt {N_c } \sigma T_g a_2 $ , with a 1=0.0823, a 2=0.30. Taking σ=0.18 GeV2 and T g=1 GeV?1, as known from analytic and lattice calculations, this yields $\left\langle {\bar qq} \right\rangle $ (μ=2 GeV)=?(0.225 GeV)3, f π=0.094 GeV, which is close to the standard values. 相似文献
62.
A. A. Yavolovskii E. V. Ganin M. S. Fonar’ Yu. A. Simonov Yu. M. Chumakov G. Bochelli 《Russian Journal of General Chemistry》2004,74(10):1605-1609
The products of the reaction of 1,2,5-thiadiazolo[3,4-d]pyrimidine-5,7-dione 2-oxide with water, viz. 1,2,5-thiadiazolo[3,4-d]pyrimidine-5,7-dione 2-oxide dihydrate and 6-amino2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-sulfamic acid, were isolated and characterized by X-ray diffraction.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 10, 2004, pp. 1728–1732.Original Russian Text Copyright © 2004 by Yavolovskii, Ganin, Fonar, Simonov, Chumakov, Bochelli.This revised version was published online in April 2005 with a corrected cover date. 相似文献
63.
Yu. A. Simonov 《Physics of Atomic Nuclei》2003,66(11):2033-2037
Some short history of three-body methods originated from the famous Skornyakov-Ter-Martirosyan equation is given, including the latest development of Faddeev formalism and Efimov states. The 3q system is shown to require an alternative, which is provided by the hyperspherical method (K harmonics), highly successful for baryons. 相似文献
64.
Yu. A. Simonov 《Physics of Atomic Nuclei》2003,66(2):338-354
The field-correlator method is used to calculate nonperturbative dynamics of quarks in a baryon. The general expression for the 3q Green’s function is obtained using the Fock-Feynman-Schwinger (world-line) path-integral formalism, where all dynamics is contained in the 3q Wilson loop with spin-field insertions. Using the lowest cumulant contribution for the Wilson loop, one obtains a Y-shaped string potential vanishing at the string-junction position. Using the einbein formalism for the quark kinetic terms, one automatically obtains constituent quark masses, calculable through the string tension. The resulting effective action for 3q plus Y-shaped strings is quantized in the path-integral formalism to produce two versions of Hamiltonian: one is in the c.m. and the other is in the light-cone system. The hyperspherical formalism is used to calculate masses and wave functions. Simple estimates in the lowest approximation yield baryon masses in good agreement with experiment without fitting parameters. 相似文献
65.
Roman Luboradzki Janusz Lipowski Yurii A. Simonov Marina S. Fonari Edward V. Ganin Arkadii A. Yavolovskii 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(1-2):59-65
The X-ray crystal structures of two closely related molecular complexes of 15-crown-5 and benzo-15-crown-5 with 3,4-diamino-1,2,5-oxadiazole are reported (I and II). Both complexes are of 1:1 stoichiometry with the host–guest alternation in the infinitechains formed due to the unsymmetrical H-bonding patterns between the components. Crystals of I are monoclinic, P21/c, a = 7.856(3), b = 12.994(1), c = 16.033(1) , = 94.79(2)°, Z = 4, final R-factor is 0.0488. Crystals of II are orthorhombic, P212121, a = 8.260(4), b = 15.692(5),c = 13.955(7) , Z = 4, final R-factor is 0.0522. 相似文献
66.
Using a nonperturbative method based on the asymptotic behavior of Wilson loops, we calculate the masses of glueballs and the corresponding Regge trajectories. The only input is the string tension fixed by the meson Regge slope, while perturbative contributions to spin splittings are defined by standard αs values. The masses of the lowest glueball states are in a perfect agreement with lattice results. The leading glueball trajectory, which is associated with the Pomeron is discussed in detail, and its mixing with f and f′ trajectories is taken into account. 相似文献
67.
68.
69.
The Lorentz nature of the effective interquark interaction is investigated in a heavy-light quarkonium. The approach of the
Dyson-Schwinger-type equation and the quantum-mechanical Hamiltonian method of the QCD string with quarks at the ends are
employed to demonstrate that the effective scalar interaction, which appears owing to chiral-symmetry breaking, is responsible
for the QCD-string formation. The Hamiltonian of the QCD string with quarks at the ends arises naturally if this effective
scalar interaction dominates. If, on the contrary, chiral symmetry is manifest, the effective interquark interaction remains
vectorial, and the corresponding bound-state equation is incompatible with the QCD-string Hamiltonian.We conclude therefore
that the genuine Lorentz nature of the QCD string is scalar.
The text was submitted by the authors in English. 相似文献
70.
O. A. Alekseeva N. I. Sorokina I. A. Verin T. Yu. Losevskaya V. I. Voronkova V. K. Yanovskii V. I. Simonov 《Crystallography Reports》2001,46(5):741-747
Single crystals of the composition K2.92Nb2.58Ti1.42P2.5O17 possessing ionic conductivity σ = 103 Ω cm?1 at 300°C were grown by the method of spontaneous crystallization from flux in the quaternary K2O-TiO2-Nb2O5-P2O5 system. The X-ray diffraction study of the single crystals grown showed that they are monoclinic with the unit-cell parameters a = 13.800(1), b = 6.412(2), c = 16.893(3) Å, β = 83.33(1)°, Z = 16, sp. gr. P2/n and provided the determination of the structure of this new compound. The Nb and Ti atoms statistically (with different probabilities) occupy four crystallographically independent octahedra. The (Nb,Ti) and P-tetrahedra form the three-dimensional framework with the channels along the diagonal [101] direction occupied by potassium atoms. 相似文献