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Kim, Y.*; Oka, Makoto; Suenaga, Daiki*; Suzuki, Kei
Physical Review D, 107(7), p.074015_1 - 074015_15, 2023/04
Times Cited Count:1 Percentile:54.75(Astronomy & Astrophysics)A chiral effective theory of scalar and vector diquarks is formulated, which is based on chiral symmetry and includes interactions between scalar and vector diquarks with one or two mesons. We find that the diquark interaction term with two mesons breaks the and flavor symmetries. To determine the coupling constants of the interaction Lagrangians, we investigate one-pion emission decays of singly heavy baryons (, and , , ), where baryons are regarded as diquark-heavy-quark two-body systems. Using this model, we present predictions of the unobserved decay widths of singly heavy baryons. We also study the change of masses and strong decay widths of singly heavy baryons under partial restoration of chiral symmetry.
Kim, Y.*; Oka, Makoto; Suzuki, Kei
Physical Review D, 105(7), p.074021_1 - 074021_17, 2022/04
Times Cited Count:15 Percentile:93.15(Astronomy & Astrophysics)Energy spectrum of doubly heavy tetraquarks, ( with and ), is studied in the potential chiral-diquark model. Using the chiral effective theory of diquarks and the quark-diquark-based potential model, the , , and tetraquarks are described as a three-body system composed of two heavy quarks and an antidiquark. We find several bound states, while no and (deep) bound state is seen. We also study the change of the tetraquark masses under restoration of chiral symmetry.
Kim, Y.*; Liu, Y.-R.*; Oka, Makoto; Suzuki, Kei
Physical Review D, 104(5), p.054012_1 - 054012_18, 2021/09
Times Cited Count:12 Percentile:74.69(Astronomy & Astrophysics)Chiral effective theory of scalar and vector diquarks is formulated according to the linear sigma model. The main application is to describe the ground and excited states of singly heavy baryons with a charm or bottom quark. Applying the potential quark model between the diquark and the heavy quark (), we construct a heavy-quark-diquark model. The spectra of the positive- and negative-parity states of , , and are obtained. The masses and interaction parameters of the effective theory are fixed partly from the lattice QCD data and also from fitting low-lying heavy baryon masses. We find that the negative parity excited states of (flavor ) are different from those of , because of the inverse hierarchy of the pseudoscalar diquark. On the other hand, and (flavor ) baryons have similar spectra. We compare our results of the heavy-quark-diquark model with experimental data as well as the quark model.
Hiyama, Emiko; Hosaka, Atsushi; Oka, Makoto; Richard, J.-M.*
Physical Review C, 98(4), p.045208_1 - 045208_8, 2018/10
Times Cited Count:43 Percentile:95.61(Physics, Nuclear)A quark model, which reproduces the ground-state mesons and baryons, i.e., the threshold energies, is applied to the configurations, where is a light quark and the charmed quark. In the calculation, several open channels are explicitly included such as , , , etc. To distinguish genuine resonances and estimate their width, we employ Gaussian Expansion Method supplemented by the real scalingmethod (stabilization). No resonance is found at the energies of the and pentaquarks. On the other hand, there is a sharp resonant state at 4690 MeV with state and another one at 4920 MeV with state, which have a compact structure.