Abstract
We investigate the quark content of the low-lying states in the sector, which are the quantum numbers of the meson, using lattice QCD. To this end, we consider correlation functions of six different two- and four-quark interpolating fields. We evaluate all diagrams, including diagrams, where quarks propagate within a time slice, e.g. with closed quark loops. We demonstrate that diagrams containing such closed quark loops have a drastic effect on the final results and, thus, may not be neglected. Our analysis, which is carried out at unphysically heavy and quark mass corresponding to and in a single spatial volume of extent 2.9 fm, shows that in addition to the expected spectrum of two-meson scattering states there is an additional energy level around the two-particle thresholds of and . This additional state, which is a candidate for the meson, couples to a quark-antiquark as well as to a diquark-antidiquark interpolating field, indicating that it is a superposition of an ordinary and a tetraquark structure. The analysis is performed using AMIAS, a novel statistical method based on the sampling of all possible spectral decompositions of the considered correlation functions, as well as solving standard generalized eigenvalue problems.
3 More- Received 8 December 2017
DOI:https://doi.org/10.1103/PhysRevD.97.034506
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society