Four-quark states in heavy quark systems

Badalyan, A.M.; Ioffe, B.L.; Smilga, Andrei

doi:10.1016/0550-3213(87)90248-3

Cited by 68 publications

(39 citation statements)

References 15 publications

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“…Note that the results obtained are in good agreement with experimental data and with the theoretical calculations reported elsewhere [10][11][12][13][14]. The calculated centers of gravity of the energy levels differ from experimental data for bottomonia by no more than 1% and for charmonia by 1.5%.…”

Section: Resultssupporting

confidence: 93%

Determination of the mass spectrum of quarkonia by the Nikiforov–Uvarov method

Maksimenko

Kuchin

2011

Russ Phys J

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The Schrödinger equation for a potential being the sum of a harmonic oscillator potential, a linear potential, and a Coulomb potential has been solved by the Nikiforov-Uvarov method for large and small distances between particles being in the bound state. Asymptotic expansions have been obtained for the energy levels and wave functions, and also the wave function and the energy of the ground state have been found. The mass spectrum of heavy quarkonia and their radius have been calculated.

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Section: Resultssupporting

confidence: 93%

Determination of the mass spectrum of quarkonia by the Nikiforov–Uvarov method

Maksimenko

Kuchin

2011

Russ Phys J

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“…Thus, only one separation coordinate (r δ − r¯δ) and only one orbital angular momentum operator L is relevant. 5 The final operator in the model for L > 0 states is the tensor coupling S 12 between the δ-δ pair, defined by…”

Section: Mass Hamiltonianmentioning

confidence: 99%

“…Theoretical studies of cccc states have a much longer history, dating indeed to a time only two years after the discovery of the J=ψ [2] and followed by a smattering of papers in the 1980s [3][4][5]. The current interest in cccc states, starting in 2011 [6,7] and particularly ramping up since 2016 [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], emerged from the expectation of dedicated searches at the LHC.…”

Section: Introductionmentioning

confidence: 99%

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Simple spectrum of cc¯cc¯ states in the dynamical diquark model

Giron

Lebed

2020

Phys. Rev. D

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We develop the spectroscopy of cccc and other all-heavy tetraquark states in the dynamical diquark model. In the most minimal form of the model (e.g., each diquark appears only in the color-triplet combination; the nonorbital spin couplings connect only quarks within each diquark), the spectroscopy is extremely simple. Namely, the S-wave multiplets contain precisely three degenerate states (0 þþ , 1 þ− , 2 þþ) and the seven P-wave states satisfy an equal-spacing rule when the tensor coupling is negligible. When comparing numerically to the recent LHCb results, we find the best interpretation is assigning Xð6900Þ to the 2S multiplet, while a lower state suggested at about 6740 MeV fits well with the members of the 1P multiplet. We also predict the location of other multiplets (1S, 1D, etc.) and discuss the significance of the cc open-flavor threshold.

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“…cannot be easily fitted in the simple qq picture of mesons [1]. These anomalous states and especially the charged ones can be considered as indications of the existence of exotic multiquark states which were predicted long ago [2,3]. Very recently the Belle Collaboration [4] observed an enhancement in e + e − → Υ(1S)π + π − , Υ(2S)π + π − , and Υ(3S)π + π − production which is not well-described by the conventional Υ(10860) line shape.…”

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confidence: 99%

Relativistic Model of Hidden Bottom Tetraquarks

2009

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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. PACS numbers: 12.40.Yx, 14.40.Gx, 12.39.Ki During last few years a significant experimental progress has been achieved in meson spectroscopy. Many new heavy meson states have been discovered. Some of them are longawaited states (such as h c , η b , etc.) while other states (such as X(3872), Y (4260), Z(4430), etc.) cannot be easily fitted in the simple qq picture of mesons [1]. These anomalous states and especially the charged ones can be considered as indications of the existence of exotic multiquark states which were predicted long ago [2,3]. Very recently the Belle Collaboration [4] observed an enhancement in e + e − → Υ(1S)π + π − , Υ(2S)π + π − , and Υ(3S)π + π − production which is not well-described by the conventional Υ(10860) line shape. One of the possible explanations is a bottomonium counterpart to the Y (4260) state which may overlap with the Υ(5S). New data on higher bottomonium excitations are expected to come in near future from KEKB, LHC and Tevatron. It is important to note that it is planned to search for bottom partners of anomalous charmonium-like states at LHC.In papers [5,6] we calculated masses of the ground and excited states of heavy tetraquarks in the framework of the relativistic quark model based on the quasipotential approach in quantum chromodynamics. It was found that most of the anomalous charmonium-like states could be interpreted as the diquark-antidiquark bound states. Here we extend this analysis to the consideration of the excited tetraquark states with hidden bottom. As previously, we use the diquark-antidiquark picture to reduce a complicated relativistic four-body problem to the subsequent two more simple two-body problems. The first step consists in the calculation of the masses, wave functions and form factors of the diquarks, composed from light and bottom quarks in the colour antitriplet state. At the second step, a bottom tetraquark is considered to be a bound diquark-antidiquark system. It is important to emphasize that the diquark is not a point particle but its structure is explicitly taken into account by calculating the diquark-gluon vertex.In the adopted approach the quark-quark bound state and diquark-antidiquark bound state are described by the diquark wave function (Ψ d ) and by the tetraquark wave function (Ψ T ), respectively. These wave functions satisfy the quasipotential equation of the

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Four-quark states in heavy quark systems

Cited by 68 publications

References 15 publications

Determination of the mass spectrum of quarkonia by the Nikiforov–Uvarov method

Determination of the mass spectrum of quarkonia by the Nikiforov–Uvarov method

Simple spectrum of cc¯cc¯ states in the dynamical diquark model

Relativistic Model of Hidden Bottom Tetraquarks

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