From well-known tensor mesons to yet unknown axial-tensor mesons

Abstract

While the ground-state tensor ($J^{PC}=2^{++}$) mesons $a_2(1320)$, $K_2^{\ast }(1430)$, $f_2(1270)$, and $f_2^{\prime }(1525)$ are well known experimentally and form an almost ideal nonet of quark-antiquark states, their chiral partners, the ground-states axial-tensor ($J^{PC}=2^{--}$) mesons are poorly settled: only the kaonic member $K_2(1820)$ of the nonet has been experimentally found, whereas the isovector state ${\rho }_2$ and two isoscalar states ${\omega }_2$ and ${\varphi }_2$ are still missing. Here, we study masses, strong, and radiative decays of tensor and axial-tensor mesons within a chiral model that links them: the established tensor mesons are used to test the model and to determine its parameters, and subsequently various predictions for their chiral partners, the axial-tensor mesons, are obtained. The results are compared to current lattice QCD outcomes as well as to other theoretical approaches and show that the ground-state axial-tensor mesons are expected to be quite broad, the vector-pseudoscalar mode being the most prominent decay mode followed by the tensor-pseudoscalar one. Nonetheless, their experimental finding seems to be possible in ongoing and/or future experiments.

Comments: 28 pages, v2: small modifications of the main text; corrected typos; added references