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

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.

scholarly journals Doubly charmed multibaryon systems

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
H. Garcilazo ◽  
A. Valcarce
Keyword(s):  
Quark Model ◽  
Bound States ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Heavy Quarks ◽  
Separation Energy ◽  
Quantum Numbers ◽  
Body State

Abstract We study two- and three-baryon systems with two units of charm looking for possible bound states or resonances. All two-baryon interactions are consistently derived from a constituent quark model tuned in the light-flavor hadron phenomenology: spectra and interactions. The presence of the heavy quarks makes the two-body interactions simpler than in the light-flavor sector. Our results show a narrow two-body resonance with quantum numbers $$(I,J^P)=(0,0^+)$$(I,JP)=(0,0+). It is located 6.2 MeV below the $$\Sigma _c\Sigma _c$$ΣcΣc threshold and has a width of 4.7 MeV. The foregoing two-body state contributes to generate a $$N \Sigma _c\Sigma _c$$NΣcΣc resonance with quantum numbers $$(I,J^P)=(1/2,1/2^+)$$(I,JP)=(1/2,1/2+) and a separation energy of 0.2 MeV.

scholarly journals Threshold effects in hadron spectrum: a new spectroscopy?

2018 ◽  
Vol 182 ◽  
pp. 02094
Author(s):  
P.G. Ortega ◽  
J. Segovia ◽  
D.R. Entem ◽  
F. Fernández
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Good Description ◽  
Bound State ◽  
Constituent Quark Model ◽  
Heavy Meson ◽  
Molecular Structures ◽  
P Wave ◽  
Model Parameters ◽  
Wide Range

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.

scholarly journals Zb structures in a constituent quark model coupled-channels calculation

2021 ◽  
Vol 104 (9) ◽  
Author(s):  
Pablo G. Ortega ◽  
Jorge Segovia ◽  
Francisco Fernández
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Coupled Channels

scholarly journals Low-lying configurations in a non-relativistic constituent quark model

2007 ◽  
Vol 34 (7) ◽  
pp. 1771-1782 ◽  
Author(s):  
W L Wang ◽  
F Huang ◽  
Z Y Zhang ◽  
Y W Yu ◽  
F Liu
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model

THE NLO QCD CALCULATION OF SEA QUARK DISTRIBUTIONS IN THE CORGI APPROACH, BASED ON THE CONSTITUENT QUARK MODEL

2007 ◽  
Vol 22 (24) ◽  
pp. 4519-4535 ◽  
Author(s):  
A. MIRJALILI ◽  
K. KESHAVARZIAN
Keyword(s):  
Quark Model ◽  
Mellin Transform ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Standard Approach ◽  
Unknown Parameters ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
Physical Scale ◽  
Good Agreement

Sea quark distributions in the NLO approximation, based on the phenomenological valon model or constituent quark model are analyzed. We use the parametrized inverse Mellin transform technique to perform a direct fit with available experimental data and obtain the unknown parameters of the distributions. We try to extend the calculation to the NLO approximation for the singlet and nonsinglet cases in DIS phenomena. We do also the same calculation for electron–positron annihilation. The resulting sea distributions are effectively independent of the process used. The approach of complete RG improvement (CORGI) is employed and the results are compared with the standard approach of perturbative QCD in the [Formula: see text] scheme with a physical scale. The comparisons with data are in good agreement. As is expected, the results in the CORGI approach indicate a better agreement to the data than the NLO calculation in the standard approach.

scholarly journals An overview of the hypercentral constituent quark model

2003 ◽  
Vol 50 (2) ◽  
pp. 263-272 ◽  
Author(s):  
M.M Giannini ◽  
E Santopinto ◽  
A Vassallo
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model

scholarly journals Electromagnetic form factors and the hypercentral constituent quark model

2007 ◽  
Vol 76 (6) ◽  
Author(s):  
M. De Sanctis ◽  
M. M. Giannini ◽  
E. Santopinto ◽  
A. Vassallo
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Form Factors ◽  
Constituent Quark Model ◽  
Electromagnetic Form Factors

scholarly journals STRUCTURE OF LIGHT AND HEAVY PENTAQUARKS

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1797-1802 ◽  
Author(s):  
FL. STANCU
Keyword(s):  
Variational Method ◽  
Hyperfine Interaction ◽  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Positive Parity ◽  
Model Based ◽  
Quantum Numbers ◽  
The Masses

Light and heavy pentaquarks are described within a constituent quark model based on a spin-flavor hyperfine interaction. In this model the lowest state acquires positive parity. The masses of the light antidecuplet members are calculated dynamically using a variational method. It is shown that the octet and antidecuplet states with the same quantum numbers mix ideally due to SU (3)F breaking. Masses of the charmed antisextet pentaquarks are predicted within the same model.

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