Regarding the enigmas ofP-wave meson spectroscopy

Abstract

The mass spectrum of $P$-wave mesons is considered in a nonrelativistic constituent quark model. The results show the common mass degeneracy of the isovector and isodoublet states of the scalar and tensor meson nonets, ${m(a}_{0})\ensuremath{\cong}{m(a}_{2}),$ ${m(K}_{0}^{*})\ensuremath{\cong}{m(K}_{2}^{*}),$ and do not exclude the possibility of a similar degeneracy of the same states of the axial-vector and pseudovector nonets. Current experimental hadronic and $\ensuremath{\tau}$-decay data suggest, however, a different scenario leading to the ${a}_{1}$ meson mass $\ensuremath{\simeq}1190$ MeV and the ${K}_{1A}$-${K}_{1B}$ mixing angle $\ensuremath{\simeq}(37\ifmmode\pm\else\textpm\fi{}3)\ifmmode^\circ\else\textdegree\fi{}.$ Possible $s\overline{s}$ states of the four nonets are also discussed.