scholarly journals Heavy Tetraquarks in the Relativistic Quark Model

Universe ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 94
Author(s):  
Rudolf N. Faustov ◽  
Vladimir O. Galkin ◽  
Elena M. Savchenko

We give a review of the calculations of the masses of tetraquarks with two and four heavy quarks in the framework of the relativistic quark model based on the quasipotential approach and QCD. The diquark-antidiquark picture of heavy tetraquarks is used. The quasipotentials of the quark-quark and diquark-antidiquark interactions are constructed similarly to the previous consideration of mesons and baryons. Diquarks are considered in the colour triplet state. It is assumed that the diquark and antidiquark interact in the tetraquark as a whole and the internal structure of the diquarks is taken into account by the calculated form factor of the diquark-gluon interaction. All parameters of the model are kept fixed from our previous calculations of meson and baryon properties. A detailed comparison of the obtained predictions for heavy tetraquark masses with available experimental data is given. Many candidates for tetraquarks are found. It is argued that the structures in the di-J/ψ mass spectrum observed recently by the LHCb collaboration can be interpreted as ccc¯c¯ tetraquarks.

Particles ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 234-244 ◽  
Author(s):  
Rudolf N. Faustov ◽  
Vladimir O. Galkin

Masses of heavy baryons are calculated in the framework of the relativistic quark-diquark picture and QCD. The obtained results are in good agreement with available experimental data including recent measurements by the LHCb Collaboration. Possible quantum numbers of excited heavy baryon states are discussed.


2005 ◽  
Vol 20 (25) ◽  
pp. 1887-1893 ◽  
Author(s):  
D. EBERT ◽  
R. N. FAUSTOV ◽  
V. O. GALKIN

The masses of the S-wave mesons consisting of the light (u, d, s) quarks are calculated within the constituent quark model. The relativistic Schrödinger-like equation with a confining potential is numerically solved for the complete relativistic [Formula: see text] potential including both spin-independent and spin-dependent terms. The obtained masses of the ground state π, ρ, K, K* and ϕ mesons and their first radial excitations are in a reasonably good overall agreement with experimental data.


2003 ◽  
Vol 18 (09) ◽  
pp. 601-607 ◽  
Author(s):  
D. EBERT ◽  
R. N. FAUSTOV ◽  
V. O. GALKIN

Two-photon decay rates of pseudoscalar, scalar and tensor states of charmonium and bottomonium are calculated in the framework of the relativistic quark model. Both relativistic effects and one-loop radiative corrections are taken into account. The obtained results are compared with other theoretical predictions and available experimental data.


1995 ◽  
Vol 108 (7) ◽  
pp. 909-916
Author(s):  
Yu. I. Ivanshin ◽  
N. B. Skachkov

2003 ◽  
Vol 12 (06) ◽  
pp. 793-807 ◽  
Author(s):  
S. M. GERASYUTA ◽  
V. I. KOCHKIN

Relativistic five-quark equations are found in the framework of the dispersion relation technique. The solutions of these equations using the method based on the extraction of the leading singularities of the amplitudes are obtained. The five-quark amplitudes for the low-lying pentaquarks are calculated under the condition that flavor SU(3) symmetry holds. The poles of the five-quark amplitudes determine the masses of the lowest pentaquarks. The mass spectra of pentaquarks which contain only light quarks are calculated. The calculation of pentaquark amplitudes estimates the contributions of three subamplitudes: molecular subamplitude BM, Mqqq subamplitude and [Formula: see text] subamplitude. The main contributions to the pentaquark amplitude are determined by the subamplitudes, which include the meson states M.


2005 ◽  
Vol 20 (24) ◽  
pp. 1813-1821
Author(s):  
S. M. GERASYUTA ◽  
V. I. KOCHKIN

The relativistic generalization of Faddeev–Yakubovsky approach is constructed in the form of the dispersion relations. The five-quark amplitudes for the low-lying pentaquarks including the u-, d-, s-quarks are calculated. The poles of these amplitudes determine the masses and widths of θ-pentaquarks.


1990 ◽  
Vol 05 (13) ◽  
pp. 2591-2604
Author(s):  
L. S. CELENZA ◽  
A. PANTZIRIS ◽  
C. M. SHAKIN ◽  
HUI-WEN WANG

We study the approach to scaling in a relativistic quark model which we have used previously to fit the experimental data for the structure function [Formula: see text] (for all x) and for [Formula: see text] (for x > 0.4). We present values for these structure functions calculated in our model and also present an analytic form which provides a good fit to the numerical results. Our model supports one form of the power-law corrections suggested in the literature. [We reproduce the sign and magnitude of the parameter which appears in a phenomenological form used in a recent analysis made by the BEBC Collaboration. Our results are also consistent with a recent BCDMS Collaboration analysis which finds no need for "higher-twist" terms for Q2 > 20 (Gev) 2.] We also discuss certain complications which may arise when one attempts to study "higher-twist" behavior at both small and large x with a single sign for the phenomenological power-law correction term. (In particular, we predict a change in sign of the power-law correction to scaling between x = 0.65 and x = 0.7.) In addition, we calculate R(x, Q2) and find a good fit to the experimental data using the same parameters which were used in our fits to [Formula: see text] and [Formula: see text].


2005 ◽  
Vol 20 (12) ◽  
pp. 875-880 ◽  
Author(s):  
D. EBERT ◽  
R. N. FAUSTOV ◽  
V. O. GALKIN

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 ηc(2S).


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