Searcharxiv⌕ Search

arXiv subjects

V. O. Galkin

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

At least 37 records · Page 2Linked to original sources
arXiv2016

Semileptonic decays of $Λ_c$ baryons in the relativistic quark model

Motivated by recent experimental progress in studying weak decays of the $Λ_c$ baryon we investigate its semileptonic decays in the framework of the relativistic quark model based on the quasipotential approach with the QCD-motivated potential. The form factors of the $Λ_c\to Λlν_l$ and $Λ_c\to nlν_l$ decays are calculated in the whole accessible kinematical region without extrapolations and additional model assumptions. Relativistic effects are systematically taken into account including transformations of baryon wave functions from the rest to moving reference frame and contributions of the intermediate negative-energy states. Baryon wave functions found in the previous mass spectrum calculations are used for the numerical evaluation. Comprehensive predictions for decay rates, asymmetries and polarization parameters are given. They agree well with available experimental data.

hep-ph↗
arXiv2016

Semileptonic decays of $Λ_b$ baryons in the relativistic quark model

Semileptonic $Λ_b$ decays are investigated in the framework of the relativistic quark model based on the quasipotential approach and the quark-diquark picture of baryons. The decay form factors are expressed through the overlap integrals of the initial and final baryon wave functions. All calculations are done without employing nonrelativistic and heavy quark expansions. The momentum transfer dependence of the decay form factors is explicitly determined in the whole accessible kinematical range without any extrapolations or model assumptions. Both the heavy-to-heavy $Λ_b\toΛ_c\ellν_\ell$ and heavy-to-light $Λ_b\to p\ellν_\ell$ decay branching fractions are calculated. The results agree within error bars with the experimental value of the branching fraction of the $Λ_b\toΛ_c^+l^-\barν_l$ decay. From the recent LHCb data on the ratio of the branching fractions of the heavy-to-light and heavy-to-heavy semileptonic $Λ_b$ decays the ratio of the Cabbibo-Kobayashi-Maskawa matrix elements $|V_{ub}|/|V_{cb}|$ is obtained. It is consistent with the corresponding ratio determined from the inclusive $B$ meson decays.

hep-ph↗
arXiv2015

Strange baryon spectroscopy in the relativistic quark model

Mass spectra of strange baryons are calculated in the framework of the relativistic quark model based on the quasipotential approach. Baryons are treated as the relativistic quark-diquark bound systems. It is assumed that two quarks with equal constituent masses form a diquark. The diquark excitations and its internal structure are consistently taken into account. Calculations are performed up to rather high orbital and radial excitations of strange baryons. On this basis the Regge trajectories are constructed. The obtained results are compared with available experimental data and previous predictions. It is found that all masses of the 4- and 3-star, as well as most of the 2- and 1-star states of strange baryons with established quantum numbers are well reproduced. The developed relativistic quark-diquark model predicts less excited states than three-quark models of strange baryons.

hep-ph↗
arXiv2015

Strong decays of vector mesons to pseudoscalar mesons in the relativistic quark model

Strong decays of vector ($^3S_1$) mesons to the pair of pseudoscalar ($^1S_0$) mesons are considered in the framework of the microscopic decay mechanism and the relativistic quark model based on the quasipotential approach. The quark-antiquark potential, which was previously used for the successful description of meson spectroscopy and electroweak decays, is employed as the source of the $q\bar q$ pair creation. The relativistic structure of the decay matrix element, relativistic contributions and boosts of the meson wave functions are comprehensively taken into account. The calculated rates of strong decays of light, heavy-light mesons and heavy quarkonia agree well with available experimental data.

hep-ph↗
arXiv2014

Relativistic description of weak decays of $B_s$ mesons

The branching fractions of the semileptonic and rare $B_s$ decays are calculated in the framework of the QCD-motivated relativistic quark model. The form factors of the weak $B_s$ transitions are expressed through the overlap integrals of the initial and final meson wave functions in the whole accessible kinematical range. The momentum transfer dependence of the form factors is explicitly determined without additional model assumptions and extrapolations. The obtained results agree well with available experimental data.

hep-ph↗
arXiv2014

Rare $B\to πl\bar l$ and $B\toρl \bar l$ decays in the relativistic quark model

The branching fractions of the rare weak $B\to πl^+l^-(ν\barν)$ and $B\toρl^+l^-(ν\barν)$ decays are calculated in the framework of the relativistic quark model based on the quasipotential approach. The form factors parametrizing weak decay matrix elements are explicitly determined in the whole kinematical $q^2$ range without additional assumptions and extrapolations. Relativistic effects are systematically taken into account including recoil effects in meson wave functions and contributions of the intermediate negative-energy states. New experimental data on the differential distributions in the semileptonic heavy-to-light $B\toπlν_l$ and $B\toρlν_l$ decays are analyzed in detail. Good agreement of the predictions and data is found. The obtained results for the branching fractions of the rare semileptonic decays are found to be in agreement with other theoretical estimates and recent experimental data available for the $B^+\toπ^+ μ^+μ^-$ decay.

hep-ph↗
arXiv2013

Rare $B_s$ decays in the relativistic quark model

The branchings fractions of the rare $B_s$ decays are calculated in the framework of the QCD-motivated relativistic quark model. The form factors of the weak $B_s$ transitions to light mesons are expressed through the overlap integral of the initial and final meson wave functions in the whole accessible kinematical range. Explicit determination of the momentum transfer dependence of the form factors without additional model assumptions and extrapolations significantly improve the reliability of the obtained results. The approximate analytical form of the form factors is given in order to simplify the comparison with other predictions and experiment. The calculated form factors are applied for the investigations of the rare semileptonic, radiative and nonleptonic $B_s$ decays. The factorization approximation is used for the description of the nonleptonic decays. All results agree well with available experimental data.

hep-ph↗
arXiv2013

Charmless weak $B_s$ decays in the relativistic quark model

The form factors of the weak $B_s$ transitions to the ground state and orbitally excited strange mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. These form factors are expressed through the overlap integrals of meson wave functions found in their mass spectrum evaluations. The momentum dependence of the form factors is determined in the whole accessible kinematical range without any additional assumptions and extrapolations. Relativistic effects, including the wave function transformation from the rest to a moving reference frame as well as contributions of the intermediate negative-energy states, are consistently taken into account. The calculated form factors are used for the evaluation of the charmless semileptonic decay rates and two-body nonleptonic $B_s$ decays in the factorization approximation. The obtained results are confronted with previous predictions and available experimental data.

hep-ph↗
arXiv2013

Weak decays of $B_s$ mesons to $D_s$ mesons in the relativistic quark model

The form factors of weak decays of $B_s$ mesons to ground state $D_s^{(*)}$ mesons as well as to their radial $D_s^{(*)}(2S)$ and orbital $D_{sJ}^{(*)}$ excitations are calculated in the framework of the relativistic quark model based on the quasipotential approach. All relativistic effects, including contributions of intermediate negative-energy states and boosts of the meson wave functions, are consistently taken into account. As a result the form factors are determined in the whole kinematical range without additional phenomenological parametrizations and extrapolations. On this basis semileptonic decay branching fractions are calculated. Two-body nonleptonic $B_s$ decays are considered within the factorization approximation. The obtained results agree well with available experimental data.

hep-ph↗
arXiv2012

Exclusive weak B decays involving $τ$ lepton in the relativistic quark model

Semileptonic and leptonic B decays are analyzed in the framework of the relativistic quark model. Special attention is payed to the decays involving $τ$ lepton. It is found that the calculated particular decay branching fractions are consistent with available experimental data within error bars. However, the predicted and recently measured ratios $R(D^{(*)})$ of the $B\to D^{(*)}τν_τ$ and $B\to D^{(*)}lν_l$ branching fractions differ by 1.75$σ$ for $R(D)$ and by 2.4$σ$ for $R(D^*)$.

hep-ph↗
arXiv2012

Exclusive semileptonic and nonleptonic decays of B mesons to orbitally excited light mesons

The form factors of weak decays of the B meson to orbitally excited scalar, axial vector and tensor light mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. Relativistic effects are systematically taken into account. The form factors are expressed trough the overlap integrals of the meson wave functions and their dependence on the momentum transfer is selfconsistently determined in the whole kinematical range. On this basis semileptonic and two-body nonleptonic B decay rates to orbitally excited light mesons are calculated. Good agreement of the obtained predictions with available experimental data is found.

hep-ph↗
arXiv2011

Spectroscopy and Regge trajectories of heavy quarkonia and B_c mesons

The mass spectra of charmonia, bottomonia and B_c mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. The dynamics of heavy quarks and antiquarks is treated fully relativistically without application of the nonrelativistic v^2/c^2 expansion. The known one-loop radiative corrections to the heavy quark potential are taken into account perturbatively. The heavy quarkonium masses are calculated up to rather high orbital and radial excitations (L=5, n_r=5). On this basis the Regge trajectories are constructed both in the total angular momentum J and radial quantum number n_r. It is found that the daughter trajectories are almost linear and parallel, while parent trajectories exhibit some nonlinearity in the low mass region. Such nonlinearity is most pronounced for bottomonia and is only marginal for charmonia. The obtained results are compared with the available experimental data, and a possible interpretation of the new charmonium-like states above open charm production threshold is discussed.

hep-ph↗
arXiv2011

Spectroscopy and Regge trajectories of heavy baryons in the relativistic quark-diquark picture

Mass spectra of heavy baryons are calculated in the heavy-quark--light-diquark picture in the framework of the QCD-motivated relativistic quark model. The dynamics of light quarks in the diquark as well as the dynamics of the heavy quark and light diquark in the baryon are treated completely relativistically without application of nonrelativistic v/c and heavy quark 1/m_Q expansions. Such approach allows us to get predictions for the heavy baryon masses for rather high orbital and radial excitations. On this basis the Regge trajectories of heavy baryons for orbital and radial excitations are constructed, and their linearity, parallelism, and equidistance are verified. The relations between the slopes and intercepts of heavy baryons are considered and a comparison of the slopes of Regge trajectories for heavy baryons and heavy-light mesons is performed. All available experimental data on heavy baryons fit nicely to the constructed Regge trajectories. The possible assignment of the quantum numbers to the observed excited charmed baryons is discussed.

hep-ph↗
arXiv2010

Masses of tetraquarks with open charm and bottom

The masses of the heavy tetraquarks with open charm and bottom are calculated within the diquark-antidiquark picture in the framework of the relativistic quark model. The dynamics of the light quarks and diquarks is treated completely relativistically. The diquark structure is taken into account by calculating the diquark-gluon form factor. New experimental data on charmed and charmed-strange mesons are discussed. Our results indicate that the anomalous scalar D_{s0}^*(2317) and axial vector D_{s1}(2460) mesons could not be considered as diquark-antidiquark bound states. On the other hand, D_s(2632) and D_{sJ}^*(2860) could be interpreted as scalar and tensor tetraquarks, respectively. The predictions for masses of the corresponding bottom counterparts of the charmed tetraquarks are given.

hep-ph↗
arXiv2010

Semileptonic and nonleptonic decays of B_c mesons to orbitally excited heavy mesons in the relativistic quark model

The form factors of weak decays of the B_c meson to orbitally excited charmonium, D, B_s and B mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. Relativistic effects are systematically taken into account. The form factor dependence on the momentum transfer is reliably determined in the whole kinematical range. The form factors are expressed trough the overlap integrals of the meson wave functions which are known from the previous mass spectra calculations within the same model. On this basis semileptonic and nonleptonic B_c decay rates to orbitally excited heavy mesons are calculated. Predictions for the B_c decays to the orbitally and radially excited 2P and 3S charmonium states are given which could be used for clarifying the nature of the recently observed charmonium-like states above the open charm production threshold.

hep-ph↗
arXiv2010

Rare semileptonic decays of B and B_c mesons in the relativistic quark model

Rare semileptonic decays of B and B_c mesons are investigated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. Form factors parametrizing the matrix elements of the weak transitions between corresponding meson states are calculated with the complete account of the relativistic effects including contributions of intermediate negative energy states and relativistic transformations of the meson wave functions. The momentum transfer dependence of the form factors is reliably determined in the whole accessible kinematical range. On this basis the total and differential branching fractions of the B\to K^{(*)}l^+l^-(ν\barν) and B_c\to D_s^{(*)}l^+l^-(ν\barν), B_c\to D^{(*)}l^+l^-(ν\barν) decays as well as the longitudinal polarization fractions F_L of the final vector meson and the muon forward-backward asymmetries A_{FB} are calculated. Good agreement of the obtained results with the recent detailed experimental data on the B\to K^{(*)}μ^+μ^- decays from Belle and CDF is found. Predictions for the rare semileptonic decays of the B_c mesons are given.

hep-ph↗
arXiv2009

Heavy-light meson spectroscopy and Regge trajectories in the relativistic quark model

Masses of the ground, orbitally and radially excited states of heavy-light mesons are calculated within the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. Both light (q=u,d,s) and heavy (Q=c,b) quarks are treated fully relativistically without application of the heavy quark 1/m_Q expansion. The Regge trajectories in the (M^2, J) and (M^2, n_r) planes are investigated and their parameters are obtained. The results are in good agreement with available experimental data except for the masses of the anomalous D^*_{s0}(2317), D_{s1}(2460) and D_{sJ}^*(2860) states.

hep-ph↗