arXiv subjects

V. O. Galkin

Publications and source records attributed to V. O. Galkin.

At least 55 records · Page 3Linked to original sources

arXiv2009

Mass spectra and Regge trajectories of light mesons in the relativistic quark model

Masses of the ground, orbitally and radially excited states of quark-antiquark mesons composed from the light (u,d,s) quarks are calculated within the framework of the relativistic quark model based on the quasipotential approach. The relativistic treatment of the light quark dynamics results in mass spectra which agree well with available experimental data for the masses of the most well-established states. The Regge trajectories for angular and radial excitations are constructed, and their linearity, parallelism and equidistance are verified. The assignment of experimentally observed light mesons to particular Regge trajectories is based on their masses and quantum numbers.

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arXiv2008

Masses of light tetraquarks and scalar mesons in the relativistic quark model

Masses of the ground state light tetraquarks are dynamically calculated in the framework of the relativistic diquark-antidiquark picture. The internal structure of the diquark is taken into account by calculating the form factor of the diquark-gluon interaction in terms of the overlap integral of the diquark wave functions. It is found that scalar mesons with masses below 1 GeV: f_0(600) (σ), K^*_0(800) (κ), f_0(980) and a_0(980) agree well with the light tetraquark interpretation.

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arXiv2008

Relativistic model of hidden bottom tetraquarks

The relativistic model of the ground state and excited heavy tetraquarks with hidden bottom is formulated within the diquark-antidiquark picture. The diquark structure is taken into account by calculating the diquark-gluon vertex in terms of the diquark wave functions. Predictions for the masses of bottom counterparts to the charm tetraquark candidates are given.

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arXiv2008

Relativistic description of the double charmonium production in $e^+e^-$ annihilation

New evaluation of the relativistic effects in the double production of $S$-wave charmonium states is performed on the basis of perturbative QCD and the relativistic quark model. The main improvement consists in the exact account of properties of the relativistic meson wave functions. For the gluon and quark propagators entering the production vertex function we use a truncated expansion in the ratio of the relative quark momenta to the center-of-mass energy $\sqrt{s}$ up to the second order. The exact relativistic treatment of the wave functions makes all such second order terms convergent, thus allowing the reliable calculation of their contributions to the production cross section. Compared to the nonrelativistic calculation we obtain a significant increase of the cross sections for the $S$-wave double charmonium production. This brings new theoretical results in good agreement with the available experimental data.

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arXiv2008

Excited heavy tetraquarks with hidden charm

The masses of the excited heavy tetraquarks with hidden charm are calculated within the relativistic diquark-antidiquark picture. The dynamics of the light quark in a heavy-light diquark is treated completely relativistically. The diquark structure is taken into account by calculating the diquark-gluon form factor. New experimental data on charmonium-like states above open charm threshold are discussed. The obtained results indicate that X(3872), Y(4260), Y(4360), Z(4248), Z(4433) and Y(4660) could be tetraquark states with hidden charm.

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arXiv2008

Relativistic description of heavy tetraquarks

The masses of the ground state and excited heavy tetraquarks with hidden charm and bottom are calculated within the relativistic diquark-antidiquark picture. The dynamics of the light quark in a heavy-light diquark is treated completely relativistically. The diquark structure is taken into account by calculating the diquark-gluon form factor. New experimental data on charmonium-like states above the open charm threshold are discussed. The obtained results indicate that X(3872), Y(4260), Y(4360), Z(4433) and Y(4660) can be tetraquark states with hidden charm.

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arXiv2007

Heavy hadrons in the relativistic quark model

Masses of heavy baryons and tetraquarks are calculated in the relativistic quark model using the heavy-quark--light-diquark and diquark-antidiquark approximations, respectively.

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arXiv2007

Masses of excited heavy baryons in the relativistic quark-diquark picture

The mass spectra of the excited heavy baryons consisting of two light (u,d,s) and one heavy (c,b) quarks are calculated in the heavy-quark--light-diquark approximation within the constituent quark model. The light quarks, forming the diquark, and the light diquark in the baryon are treated completely relativistically. The expansion in v/c up to the second order is used only for the heavy (b and c) quarks. The internal structure of the diquark is taken into account by inserting the diquark-gluon interaction form factor. An overall good agreement of the obtained predictions with available experimental data is found.

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arXiv2007

Masses of tetraquarks with two heavy quarks in the relativistic quark model

Masses of tetraquarks with two heavy quarks and open charm and bottom are calculated in the framework of the diquark-antidiquark picture in the relativistic quark model. All model parameters were regarded as fixed by previous considerations of various properties of mesons and baryons. The light quarks and diquarks are treated completely relativistically. The c quark is assumed to be heavy enough to make the diquark configurations dominating. The diquarks are considered not to be point-like but to have an internal structure which is taken into account by the calculated diquark form factor entering the diquark-gluon interaction. It is found that all the (cc)(\bar q\bar q') tetraquarks have masses above the thresholds for decays into open charm mesons. Only the I(J^P)=0(1^+) state of (bb)(\bar u\bar d) lies below the BB* threshold and is predicted to be narrow.

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arXiv2006

New analysis of semileptonic B decays in the relativistic quark model

We present the new analysis of the semileptonic B decays in the framework of the relativistic quark model based on the quasipotential approach. Decays both to heavy D^{(*)} and light π(ρ) mesons are considered. All relativistic effects are systematically taken into account including contributions of the negative-energy states and the wave function transformation from the rest to moving reference frame. For heavy-to-heavy transitions the heavy quark expansion is applied. Leading and subleading Isgur-Wise functions are determined as the overlap integrals of initial and final meson wave functions. For heavy-to-light transitions the explicit relativistic expressions are used to determine the dependence of the form factors on the momentum transfer squared. Such treatment significantly reduces theoretical uncertainties and increases reliability of obtained predictions. All results for form factors, partial and total decay rates agree well with recent experimental data and unquenched lattice calculations. From this comparison we find the following values of the Cabibbo-Kobayashi-Maskawa matrix elements: |V_{cb}|=(3.85\pm0.15\pm 0.20)*10^{-2} and |V_{ub}|=(3.82\pm0.20\pm0.20)*10^{-3}, where the first error is experimental and the second one is theoretical.

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arXiv2006

Relativistic description of semileptonic decays of heavy baryons

Semileptonic decays of heavy baryons consisting of one heavy (Q=b,c) and two light (q=u,d,s) quarks are considered in the heavy-quark--light-diquark approximation. The relativistic quasipotential equation is used for obtaining masses and wave functions of both diquarks and baryons within the constituent quark model. The weak transition matrix elements are expressed through the overlap integrals of the baryon wave functions. The Isgur-Wise functions are determined in the whole accessible kinematic range. The exclusive semileptonic decay rates are calculated with applying the heavy quark 1/m_Q expansion. The evaluated Lambda_b -> Lambda_c l nu decay rate agrees with its experimental value.

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arXiv2006

Masses and electroweak properties of light mesons in the relativistic quark model

The masses, pseudoscalar and vector weak decay constants and electromagnetic form factors of light S-wave mesons are studied in the framework of the relativistic quark model based on the quasipotential approach. We use the same model assumptions and parameters as in our previous investigations of heavy meson and baryon properties. The masses and wave functions of the ground state and radially excited pi, rho, K, K* and phi mesons, obtained by solving numerically the relativistic Schroedinger-like equation with the complete relativistic q bar q potential including both spin-independent and spin-dependent terms, are presented. Novel relativistic expressions for the weak decay constants of the pseudoscalar and vector mesons are derived. It is shown that the intermediate negative-energy quark states give significant contributions which essentially decrease the decay constants bringing them in agreement with experimental data. The electromagnetic form factors of the pion, charged and neutral kaon are calculated in a broad range of the space-like momentum transfer. The corresponding charge radii are determined. All results agree well with available experimental data.

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arXiv2006

Relativistic treatment of the decay constants of light and heavy mesons

Novel relativistic expressions are used to calculate the weak decay constants of pseudoscalar and vector mesons within the constituent quark model. Meson wave functions satisfy the quasipotential equation with the complete relativistic potential. New contributions, coming from the negative-energy quark states, are substantial for the light mesons, significantly decrease the values of their decay constants and, thus, bring them into agreement with experiment. For heavy-light mesons these contribution are much less pronounced, but permit to reduce uncertainties of the predicted decay constants. Their values agree with the results of lattice calculations and experimental data.

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arXiv2006

Semileptonic decays of heavy baryons in the relativistic quark model

Semileptonic decays of heavy baryons consisting of one heavy (Q=b,c) and two light (q=u,d,s) quarks are considered in the heavy-quark--light-diquark approximation. The relativistic quasipotential equation is used for obtaining masses and wave functions of both diquarks and baryons within the constituent quark model. The weak transition matrix elements are expressed through the overlap integrals of the baryon wave functions. The Isgur-Wise functions are determined in the whole accessible kinematic range. The exclusive semileptonic decay rates and different asymmetries are calculated with applying the heavy quark 1/m_Q expansion. The evaluated Lambda_b -> Lambda_c l nu decay rate agrees with its experimental value.

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arXiv2006

Masses of heavy tetraquarks in the relativistic quark model

The masses of heavy tetraquarks with hidden charm and bottom are calculated in the framework of the relativistic quark model. The tetraquark is considered as the bound state of a heavy-light diquark and antidiquark. The light quark in a heavy-light diquark is treated completely relativistically. The internal structure of the diquark is taken into account by calculating the diquark-gluon form factor in terms of the diquark wave functions. New experimental data on charmonium-like states above open charm threshold are discussed. The obtained results indicate that the X(3872) can be the tetraquark state with hidden charm. The masses of ground state tetraquarks with hidden bottom are found to be below the open bottom threshold.

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arXiv2005

Masses of heavy baryons in the relativistic quark model

The masses of the ground state heavy baryons consisting of two light (u,d,s) and one heavy (c,b) quarks are calculated in the heavy-quark--light-diquark approximation within the constituent quark model. The light quarks, forming the diquark, and the light diquark in the baryon are treated completely relativistically. The expansion in v/c up to the second order is used only for the heavy (b and c) quarks. The diquark-gluon interaction is taken modified by the form factor describing the light diquark structure in terms of the diquark wave functions. An overall reasonable agreement of the obtained predictions with available experimental data and previous theoretical results is found.

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arXiv2005

Masses of light mesons in the relativistic quark model

The masses of the S-wave mesons consisting of the light (u,d,s) quarks are calculated within the constituent quark model. The relativistic Schroedinger-like equation with a confining potential is numerically solved for the complete relativistic q bar q potential including both spin-independent and spin-dependent terms. The obtained masses of the ground-state pi, rho, K, K* and phi mesons and their first radial excitations are in reasonably good overall agreement with experimental data.

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arXiv2005

Relativistic description of the charmonium mass spectrum

The charmonium mass spectrum is considered in the framework of the constituent quark model with the relativistic treatment of the c quark. The obtained masses are in good agreement with the existing experimental data including the mass of eta_c(2S).

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