We investigate the quark content of the low-lying states in the I(JP)=1(0+) sector, which are the quantum numbers of the a0(980) 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 u and d quark mass corresponding to mπ=296(3) MeV 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 K+K̄ and η+π. This additional state, which is a candidate for the a0(980) meson, couples to a quark-antiquark as well as to a diquark-antidiquark interpolating field, indicating that it is a superposition of an ordinary q̄q 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.
Alexandrou, C., Berlin, J., Dalla Brida, M., Finkenrath, J., Leontiou, T., & Wagner, M. (2018). Lattice QCD investigation of the structure of the a 0 (980) meson. PHYSICAL REVIEW D, 97(3).
|Citazione:||Alexandrou, C., Berlin, J., Dalla Brida, M., Finkenrath, J., Leontiou, T., & Wagner, M. (2018). Lattice QCD investigation of the structure of the a 0 (980) meson. PHYSICAL REVIEW D, 97(3).|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Presenza di un coautore afferente ad Istituzioni straniere:||Si|
|Titolo:||Lattice QCD investigation of the structure of the a 0 (980) meson|
|Autori:||Alexandrou, C; Berlin, J; Dalla Brida, M; Finkenrath, J; Leontiou, T; Wagner, M|
|Data di pubblicazione:||2018|
|Rivista:||PHYSICAL REVIEW D|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1103/PhysRevD.97.034506|
|Appare nelle tipologie:||01 - Articolo su rivista|