Multiquark resonances

Esposito, Angelo; Pilloni, A.; Polosa, A. D.

doi:10.1016/j.physrep.2016.11.002

Cited by 759 publications

(675 citation statements)

References 431 publications

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“…Together with the spin-0 or -1 cc pair, there exist five spin-1/2, four spin-3/2, and one spin-5/2 q 4 q (0s) 5 states. The number of S-wave meson-baryon states is seven for J = 1/2, five for J = 3/2, and one for The normalization of such states reduces to zero.…”

Section: Comparison With the Quark Cluster Modelmentioning

confidence: 99%

Hidden-charm and bottom meson-baryon molecules coupled with five-quark states

et al. 2017

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In this paper, we investigate the hidden-charm pentaquarks asD ( * ) Λ c andD ( * ) Σ ( * ) c molecules coupled to the five-quark states. Furthermore, we extend our calculations to the hidden-bottom sector. The coupling to the five-quark states is treated as the short range potential, where the relative strength for the meson-baryon channels is determined by the structure of the five-quark states. We found that resonant and/or bound states appear in both the charm and bottom sectors.The five-quark state potential turned out to be attractive and, for this reason, it plays an important role to produce these states. In the charm sector, we need the five-quark potential in addition to the pion exchange potential in producing bound and resonant states, whereas, in the bottom sector, the pion exchange interaction is strong enough to produce states. Thus, from this investigation, it emerges that the hidden-bottom pentaquarks are more likely to form than their hidden-charm counterparts; for this reason, we suggest that the experimentalists should look for states in the bottom sector.

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Section: Comparison With the Quark Cluster Modelmentioning

confidence: 99%

Hidden-charm and bottom meson-baryon molecules coupled with five-quark states

et al. 2017

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“…In the last years the interest in charmonia has been renewed by the experimental observation of new charmoniumlike states [1][2][3][4][5][6][7]. Some of these states have been easily identified as charmonia, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…However there exist other important resonances that are still under examination. These states, denoted as X, Y and Z, do not match the predictions of the nonrelativistic or semirelativistic qq potential models and some of them have been described as tetraquarks, molecules, glueballs and hybrids [3][4][5][6][7][12][13][14][15][16][17][18]. Another possible explanation suggests that some of these states may be the result of kinematic effects [19,20] that appear in the nearby of the thresholds of the open charm channels.…”

Section: Introductionmentioning

confidence: 99%

Charmonium spectrum with a Dirac potential model in the momentum space

2017

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We study the charmonium spectrum using a complete one gluon exchange approach based on a phenomenological relativistic qq potential model with Dirac spinors in momentum space. We use phenomenological screening factors to include vacuum quantum effects. Our formulation does not rely on nonrelativistic approximations. We fit the lowest-lying charmonia (below the DD threshold) and predict the higher-lying resonances of the spectrum. In general, we reproduce the overall structure of the charmonium spectrum and, in particular, we can reasonably describe the X(3872) resonance mass as (mostly) a cc state. The numerical values of the free parameters of the model are determined taking into account also the experimental uncertainties of the resonance energies. In this way, we are able to obtain the uncertainties of the theoretical resonance masses and the correlation among the free parameters of the model.

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“…These puzzles have been discussed exhaustively in the literatures (see refs. [10][11][12] for example), but a consistent description is still missing.In this paper, we adopt the idea of Gamow states and the solvable extended Friedrichs model developed recently [13][14][15], usually discussed in the pure mathematical physics literature, to study the resonance phenomena in the hadron physics, in particular the charmonium spectrum. Using the eigenvalues and wave functions for mesons in the Godfrey-Isgur (GI) model [3] as input and modelling the interaction by the quark pair production (QPC) model, we found that the first excited 2 ++ , 1 ++ , and 0 ++ charmonium states could be reproduced with good accuracy in an one-parameter calculation, and the mass and width of 1 +− state are also obtained as a prediction.…”

mentioning

confidence: 99%

“…These puzzles have been discussed exhaustively in the literatures (see refs. [10][11][12] for example), but a consistent description is still missing.…”

mentioning

confidence: 99%

Understanding X(3862) , X(3872) , and
Zhou
¹
,
Xiao
²

2017
Phys. Rev. D

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We developed a Friedrichs-model-like scheme in studying the hadron resonance phenomenology and present that the hadron resonances might be regarded as the Gamow states produced by a Hamiltonian in which the bare discrete state is described by the result of usual quark potential model and the interaction part is described by the quark pair creation model. In a one-parameter calculation, the X(3862), X(3872), and X(3930) state could be simultaneously produced with a quite good accuracy by coupling the three P-wave states, χc2(2P ), χc1(2P ), χc0(2P ) predicted in the Godfrey-Isgur model to the DD, DD * , D * D * continuum states. At the same time, we predict that the hc(2P ) state is at about 3902 MeV with a pole width of about 54 MeV. In this calculation, the X(3872) state has a large compositeness. This scheme may shed more light on the long-standing problem about the general discrepancy between the prediction of the quark model and the observed values, and it may also provide reference for future search for the hadron resonance state.PACS numbers: 12.39. Jh, 13.25.Gv, 13.75.Lb, 11.55.Fv As regards the charmonium spectrum above the openflavor thresholds, general discrepancies between the predicted masses in the quark potential model and the observed values have been highlighted for several years. Typically, among the P-wave n 2s+1 L J = 2 3 P 2 , 2 3 P 1 , 2 3 P 0 , and 2 1 P 1 states, the X(3930), discovered by the Belle Collaboration [1], is now assigned to χ c2 (2P ) charmonium state though its mass is about 50 MeV lower than the prediction in the quark potential model [2][3][4]. The properties of the other P-wave states have not been firmly determined yet. The X(3872) was first observed in the B ± → K ± J/ψπ + π − by the Belle Collaboration in 2003 [5]. Although its quantum number is 1 ++ , the same as the χ c1 (2P ), the pure charmonium interpretation was soon given up for the difficulties in explaining its decays. The pure molecular state explanation of X(3872) also encounters difficulties in understanding its radiative decays. So its nature remains to be obscure up to now. As for the χ c0 (2P ) state, the X(3915) is assigned to it several years ago, but this assignment is questioned for the mass splitting between χ c2 (2P ) and χ c0 (2P ), and its dominant decay mode [6,7]. In Ref.[8], analyses of the angular distribution of X(3915) to the final leptonic and pionic states also support the possibility of being a 2 ++ state, which means that it might be the same tensor state as the X(3930). Very recently, the Belle Collaboration announced a new result about the signal of X(3862) which could be a candidate for the χ c0 (2P ) [9]. The 2 1 P 1 state has not been discovered yet. These puzzles have been discussed exhaustively in the literatures (see refs. [10][11][12] for example), but a consistent description is still missing.In this paper, we adopt the idea of Gamow states and the solvable extended Friedrichs model developed recently [13][14][15], usually discussed in the pure mathematical physics literatur...

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Multiquark resonances

Cited by 759 publications

References 431 publications

Hidden-charm and bottom meson-baryon molecules coupled with five-quark states

Hidden-charm and bottom meson-baryon molecules coupled with five-quark states

Charmonium spectrum with a Dirac potential model in the momentum space

Understanding X(3862) , X(3872) , and
Zhou
¹
,
Xiao
²

2017
Phys. Rev. D

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Multiquark resonances

Cited by 759 publications

References 431 publications

Hidden-charm and bottom meson-baryon molecules coupled with five-quark states

Hidden-charm and bottom meson-baryon molecules coupled with five-quark states

Charmonium spectrum with a Dirac potential model in the momentum space

Understanding X(3862) , X(3872) , and Zhou1, Xiao2 2017Phys. Rev. D

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Resources

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Understanding X(3862) , X(3872) , and
Zhou
¹
,
Xiao
²

2017
Phys. Rev. D