TetraQuark Resonances in Lattice QCD
Abstract
We study qq bar{q}bar{q}type fourquark (4Q) systems in SU(3)_c anisotropic quenched lattice QCD, using the O(a)improved Wilson (clover) fermion at β = 5.75 on 12^3 × 96 with renormalized anisotropy a_s/a_t = 4. For comparison, we first investigate the lowest qbar{q} scalar meson from the connected diagram and find its large mass of about 1.32 GeV after chiral extrapolation, and thus the lowest qbar{q} scalar meson corresponds to f_0(1370). We investigate the lowest 4Q state in the spatially periodic boundary condition, and find that it is just a twopion scattering state, as is expected. To examine spatiallylocalized 4Q resonances, we use the Hybrid Boundary Condition (HBC) method, where antiperiodic and periodic boundary conditions are imposed on quarks and antiquarks, respectively. By applying HBC on a finitevolume lattice, the threshold of the twomeson scattering state is raised up, while the mass of a compact 4Q resonance is almost
unchanged. In HBC, the lowest 4Q state appears slightly below the twomeson threshold. To clarify the nature of the 4Q system, we apply the Maximum Entropy Method (MEM) for the 4Q correlator and obtain the spectral function of the 4Q system. From the combination analysis of MEM with HBC, we finally conclude that the 4Q system appears as a twopion scattering state and there is no spatiallylocalized 4Q resonance in the quarkmass region of m_s < m_q < 2m_s.
 Publication:

Progress of Theoretical Physics Supplement
 Pub Date:
 2007
 DOI:
 10.1143/PTPS.168.168
 arXiv:
 arXiv:0707.3309
 Bibcode:
 2007PThPS.168..168S
 Keywords:

 High Energy Physics  Lattice
 EPrint:
 Prog.Theor.Phys.Suppl.168:168172,2007