Toward the excited meson spectrum of dynamical QCD

Abstract

We present a detailed description of the extraction of the highly excited isovector meson spectrum on dynamical anisotropic lattices using a new quark-field construction algorithm and a large variational basis of operators. With careful operator construction, the combination of these techniques is used to identify the continuum spin of extracted states reliably, overcoming the reduced rotational symmetry of the cubic lattice. Excited states, states with exotic quantum numbers (0 +− , 1 −+ and 2 +− ) and states of high spin are resolved, including, for the first time in a lattice QCD calculation, spin-four states. The determinations of the spectrum of isovector mesons and kaons are performed on dynamical lattices with two volumes and with pion masses down to ∼ 400 MeV, with statistical precision typically at or below 1% even for highly excited states.

S-waveKK*interactions in a finite volume and thefGeng1, Ren2, Zhou3 et al. 2015Phys. Rev. D292330View full textAdd to dashboardCite

“…There has been much work done along these lines recently. By using qq interpolators [66][67][68][69] new methods and suitable interpolators have been developed to project on the desired spin states. More relevant to our problem, using the Lüscher formalism for scattering of two particles, several papers have dealt with this problem.…”

Hybrid mesons

“…We also note that the production of this state is consistent (natural parity exchange) for both of the observed final states. In the case that the π 1 (1600) is associated with the lowest-mass hybrid state, one possible interpretation of the π 1 (2015) would be an excited state (as suggested by recent LQCD calculations [37]). The mass splitting is typical of radial excitations observed in the normal mesons.…”

“…Developing a phenomenological model for these observations is an interesting task. [27], open (cyan) squares [32], open (cyan) upright triangles [34], open (cyan) circles [33], solid (red) downward triangles [35], solid (red) squares [36], solid (blue) upright triangles [34] and solid (blue) circles [37].…”

Coupled-channel Dπ, Dη and D s K ¯ $$ {D}_s\overline{K} $$ scattering from lattice QCD

“…In order to robustly extract many energy levels in each channel we follow our well established procedure [46]: a matrix of two-point correlation functions, C ij (t), is computed using a basis of operators with the relevant quantum numbers. A variational procedure [47] is employed, which amounts to solving a generalised eigenvalue problem,…”