Charmonium spectroscopy from an anisotropic lattice study

Abstract

We present a progress report on our study of the charmonium spectrum in full QCD on anisotropic lattices generated by the Hadron Spectrum Collaboration. We adopt a large basis of interpolating operators to extract the excited charmonium states using the variational method. A detailed spectrum of excited charmonium mesons in many J PC channels is obtained. Hybrid states with exotic and non-exotic quantum numbers are determined and preliminary results from a study of disconnected contributions to the η c are presented.

QCD Sum Rule Studies of Heavy Quarkonium-like States

“…There has also been an attempt to describe it as a charmonium hybrid [77]. However, the hybrid interpretation has been largely set aside due to the fact that several different theoretical approaches predict an axial vector charmonium hybrid mass that is much greater than that of the X(3872) [17,99,79,78]. With the mass predictions that we have extracted, QSR is now in agreement with these other theoretical approaches.…”

Excited and exotic charmonium spectroscopy from lattice QCD

“…Nevertheless, in the distillation framework we can efficiently compute these contributions and determine their effect on the spectrum. This has already been done in the isoscalar light meson spectrum [12] and by applying the same methodology to charmonium we can determine the mixings between cc, ss and 1 √ 2 uū + d d basis states; these calculations are ongoing [16].…”

Possible $J^{PC} = 0^{+-}$ Exotic State

“…For the bottomnium-like 0 +− states, their masses are about 11.2 ∼ 11.3 GeV. It's very interesting to note that the mass of the 0 +− charmonium-like state extracted from the tetraquark sum rules is numerically quite close to the mass of the 0 +− hybrid charmonium extracted on the lattice [12,13].…”