Threshold effects in hadron spectrum: a new spectroscopy?

The exploration of energies above the open-flavor threshold in the meson spectra has led to the appearance of unexpected states difficult to accommodate in the naive picture of a bound state of a quark and an antiquark. Many of such states are located close to meson-meson thresholds, which suggests that molecular structures may be a relevant component in the total wave function of such resonances. In this work, the state of meson-meson molecules calculations is reviewed, using a nonrelativistic constituent quark model that has been applied to a wide range of hadronic observables, and therefore all model parameters are completely constrained. The model has been able to reproduce, among others, the properties of the X(3872), described as a mixture of cc and DD* states, or the spectrum of the P-wave charm-strange mesons, which are well reproduced only if DK and D*K structures are taken into account. We show that such constituent quark model, which is able to describe the ordinary heavy meson spectra, is also capable of providing a good description of many new states recently reported.

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The charged $Z_c$ and $Z_b$ structures in a constituent quark model approach

SciPost Physics Proceedings ◽

10.21468/scipostphysproc.3.013 ◽

2020 ◽

Author(s):

Pablo G. Ortega ◽

Jorge Segovia ◽

David Rodriguez Entem ◽

Francisco Fernández

Keyword(s):

Quark Model ◽

Constituent Quark ◽

Constituent Quark Model ◽

Heavy Quarks ◽

Coupled Channels ◽

Wide Range ◽

Quark Content ◽

Model Approach

The nature of the recently discovered Z_cZc and Z_bZb structures is intriguing. Their charge forces its minimal quark content to be Q\bar Q q\bar qQQ‾qq‾ (where Q=\{c,b\}Q={c,b} and q=\{u,d\}q={u,d}). In this work we perform a molecular coupled-channels calculation of the I^G(J^{PC})=1^+(1^{+-})IG(JPC)=1+(1+−) charm and bottom sectors in the framework of a constituent quark model which satisfactorily describes a wide range of properties of (non-)conventional hadrons containing heavy quarks. All the relevant channels are included for each sector, i.e.: The D^{(\ast)}\bar D^{\ast}+h.c.D(*)D‾*+h.c., \pi J/\psiπJ/ψ and \rho\eta_cρηc channels for the Z_cZc and B^{(\ast)}B^{\ast}B(*)B* and \Upsilon(nS)\piΥ(nS)π (n=1,2,3n=1,2,3) channels for the Z_bZb analysis. Possible structures of these resonances will be discussed.

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HEAVY FLAVOUR HADRONIC MOLECULES

International Journal of Modern Physics A ◽

10.1142/s0217751x11052207 ◽

2011 ◽

Vol 26 (03n04) ◽

pp. 613-615

Author(s):

P. G. ORTEGA ◽

D. R. ENTEM ◽

F. FERNÁNDEZ

Keyword(s):

Quark Model ◽

Constituent Quark ◽

Bound State ◽

Constituent Quark Model ◽

Charmonium State ◽

Decay Modes

The structure and different decay modes of the X(3872) resonance are described in a constituent quark model as dynamically generated by the coupling of a molecular DD* state with a [Formula: see text] state. We also obtain in the D*D* JPC = 1-- channel a bound state that can be identify with the Y(4008) charmonium state. Other possible molecular states in the hidden bottom sector are discussed.

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An Effective Theory approach to $\bar{B}_s$ mesons involving $SU(3)$ heavy meson symmetry and constituent quark-model states

10.22323/1.310.0039 ◽

2018 ◽

Author(s):

Pedro Fernandez-Soler ◽

Miguel Albaladejo ◽

Juan Nieves ◽

Pablo G. Ortega

Keyword(s):

Quark Model ◽

Constituent Quark ◽

Constituent Quark Model ◽

Heavy Meson ◽

Effective Theory ◽

Theory Approach

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STUDY OF $N\bar{N}$ INTERACTION WITH CHANNEL-COUPLING IN CONSTITUENT QUARK MODELS

Modern Physics Letters A ◽

10.1142/s0217732311035481 ◽

2011 ◽

Vol 26 (16) ◽

pp. 1231-1241 ◽

Cited By ~ 2

Author(s):

HONGXIA HUANG ◽

HOURONG PANG ◽

JIALUN PING

Keyword(s):

Radiative Decay ◽

Constituent Quark ◽

Good Description ◽

Bound State ◽

Nucleon Nucleon ◽

Group Method ◽

Model Parameters ◽

S Wave ◽

Channel Coupling ◽

Quark Models

The nucleon–antinucleon interaction is studied by using resonating-group-method in the framework of two constituent quark models: the chiral quark model and the quark delocalization color screening model, which can give a good description of baryon properties and nucleon–nucleon interaction. The experimental data of proton–antiproton S-wave elastic scattering cross-section can be well reproduced by adjusting properly one-gluon annihilation coupling constant. With the fixed model parameters, a dynamical calculation of all possible S-wave nucleon–antinucleon states with channel-coupling is performed. The calculated results show that the effect of channel-coupling is not strong to form a bound state as indicated by a strong enhancement at threshold of [Formula: see text] in J/ψ radiative decay.

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POSSIBLE MOLECULAR STRUCTURES IN THE HEAVY BARYON SPECTRUM

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194514601239 ◽

2014 ◽

Vol 26 ◽

pp. 1460123

Author(s):

D. R. ENTEM ◽

P. G. ORTEGA ◽

F. FERNÁNDEZ

Keyword(s):

Experimental Data ◽

Bound States ◽

Constituent Quark ◽

Heavy Baryon ◽

Bound State ◽

Constituent Quark Model ◽

Molecular Structures ◽

Baryon Spectrum ◽

Small Binding Energy ◽

Bottom Baryon

We use a chiral constituent quark model to study possible molecular structures in the heavy baryon spectrum. We first analyze D*N states and we find a bound state in the JP = 3/2- sector with an small binding energy. This state can be identified with the Λc(2940)+. The decays of this state are compatible with the existent experimental data. As a by product a state is predicted in the bottom baryon spectrum as a [Formula: see text] state with a mass around 6250 MeV. Moreover we also analyze other DN, D*N, DΔ and D*Δ states and their analogs in the bottom baryon sector finding several bound states.

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The effect of instanton-induced interaction on P-wave meson spectra in constituent quark model

Pramana ◽

10.1007/s12043-008-0006-3 ◽

2008 ◽

Vol 70 (1) ◽

pp. 75-85 ◽

Cited By ~ 5

Author(s):

Bhavyashri ◽

S. Sarangi ◽

Godfrey Saldanha ◽

K. B. Vijaya Kumar

Keyword(s):

Quark Model ◽

Constituent Quark ◽

Constituent Quark Model ◽

P Wave

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STUDY OF $p\bar{\Lambda}$ AND $p\bar{\Sigma}$ SYSTEMS IN CONSTITUENT QUARK MODELS

Modern Physics Letters A ◽

10.1142/s0217732312500393 ◽

2012 ◽

Vol 27 (10) ◽

pp. 1250039

Author(s):

HONGXIA HUANG ◽

JIALUN PING ◽

FAN WANG

Keyword(s):

Elastic Scattering ◽

Constituent Quark ◽

Good Description ◽

Resonance State ◽

Bound State ◽

Model Parameters ◽

S Wave ◽

Proton Antiproton ◽

Screening Model ◽

Quark Models

The [Formula: see text] systems with J = 0 and J = 1 are dynamically investigated within the framework of two constituent quark models: the chiral quark model and the quark delocalization color screening model. The model parameters are taken from our previous work, which gave a good description of the proton–antiproton S-wave elastic scattering cross-section experimental data. The [Formula: see text] elastic scattering processes with coupling to [Formula: see text] state are studied. The results show that, there is no s-wave bound state as indicated by an enhancement near the threshold of [Formula: see text] in J/ψ decay. However, a [Formula: see text] resonance state is given in the quark delocalization color screening model.

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Strange hidden-charm tetraquarks in constituent quark model

The European Physical Journal C ◽

10.1140/epjc/s10052-021-09916-w ◽

2021 ◽

Vol 81 (12) ◽

Author(s):

Xin Jin ◽

Yuheng Wu ◽

Xuejie Liu ◽

Hongxia Huang ◽

Jialun Ping ◽

...

Keyword(s):

Quark Model ◽

Constituent Quark ◽

Bound State ◽

Constituent Quark Model ◽

Molecular State ◽

Resonance States ◽

Effective Potentials ◽

Coupling Calculation ◽

Bound State Calculation ◽

Exotic Hadron

AbstractIn the framework of the chiral quark model (ChQM), we systematically investigate the strange hidden-charm tetraquark systems $$cs{\bar{c}}{\bar{u}}$$ c s c ¯ u ¯ with two structures: $$q{\bar{q}}-q{\bar{q}}$$ q q ¯ - q q ¯ and $$qq-{\bar{q}}{\bar{q}}$$ q q - q ¯ q ¯ . The bound-state calculation shows that there is no any bound state in present work, which excludes the molecular state explanation ($$D^{0}D_{s}^{*-}/D^{*0}D_{s}^{-}/D^{*0}D_{s}^{*-}$$ D 0 D s ∗ - / D ∗ 0 D s - / D ∗ 0 D s ∗ - ) of the reported $$Z_{cs}(3985)^{-}$$ Z cs ( 3985 ) - or $$Z_{cs}(4000)^{+}$$ Z cs ( 4000 ) + . However, the effective potentials for the $$cs-{\bar{c}}{\bar{u}}$$ c s - c ¯ u ¯ systems show the possibility of some resonance states. By applying a stabilization calculation and coupling all channels of both two structures, two new resonance states are obtained, which are the $$IJ^{P}=\frac{1}{2} 0^{+}$$ I J P = 1 2 0 + state with the energy around 4111–4116 MeV and the $$IJ^{P} =\frac{1}{2} 1^{+}$$ I J P = 1 2 1 + state with energy around 4113–4119 MeV, respectively. Both of them are worthy of search in future experiments. Our results show that the coupling calculation between the bound channels and open channels is indispensable to provide the necessary information for experiments to search for exotic hadron states.

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EXCLUSIVE PRODUCTION OF HEAVY MESON PAIRS IN e+e− ANNIHILATION

International Journal of Modern Physics A ◽

10.1142/s0217751x95000206 ◽

1995 ◽

Vol 10 (04) ◽

pp. 465-476 ◽

Cited By ~ 10

Author(s):

V. V. KISELEV

Keyword(s):

Pair Production ◽

Heavy Quark ◽

Quark Model ◽

Constituent Quark ◽

Constituent Quark Model ◽

Heavy Meson ◽

Leading Order ◽

Exclusive Production ◽

Quark Theory

A constituent quark model is used to calculate the exclusive pair production of [Formula: see text] and [Formula: see text] mesons in e+e− annihilation. It allows one to illuminate the meaning of the 1/mb,c corrections to the leading order of the effective heavy quark theory.

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