Search

Low-lying baryon resonances have been explored using Hamiltonian Effective Field Theory (HEFT), in a formalism where resonances with a three-quark component are described by both two-particle meson–baryon states and a bare basis state. Here, we investigate the use of multiple bare states in the Hamiltonian, to extend the formalism to higher energy ranges, and represent a larger portion of the low-lying baryon spectrum. Introducing a second bare state into a toy model extension of the low-energy Δ (1232) system, we explore the influence of the second bare state on the position of poles in the infinite-volume T -matrix. Considering the same system in a finite-volume, we analyse the finite-volume energy spectrum in the presence of a second bare state, providing insight into the interplay between two bare basis states, representing quark-model states, and the relationship between infinite-volume poles and finite-volume eigenstates. • Hamiltonian Effective Field Theory is formulated using multiple bare basis states. • A toy model extension of the P33 pion nucleon system is considered. • The positions of poles in the scattering matrix are found. • The finite-volume energy spectrum is found for the two bare state system. [ABSTRACT FROM AUTHOR]

Spectrum of the doubly heavy tetraquarks is studied in a constituent quark model including one-pion exchange (OPE) potential. Central and tensor forces induced by OPE between two light quarks are considered. Our results show that I (J P) = 0 (1 +) compact bound states are shifted up because of the repulsive central force between q ¯ q ¯. This effect possibly leads to the small binding energy in T c c. In addition, a I (J P) = 1 (1 +) resonant state is reported with E = 10641 MeV , Γ = 15 MeV and E = 10640 MeV , Γ = 15 MeV , without and with including OPE potential, respectively. The repulsive central force and attractive tensor force almost cancel with each other and leave a small energy difference when OPE potential is included. [ABSTRACT FROM AUTHOR]