Toward establishing an abundant <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>B</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:math> spectrum up to the second orbital excitations
Qi Li, Ru-Hui Ni, Xian-Hui Zhong
Abstract
Stimulated by the exciting progress in experiments, we carry out a combined analysis of the masses, and strong and radiative decay properties of the $B$ and ${B}_{s}$-meson states up to the second orbital excitations. Based on our good descriptions of the mass and decay properties for the low-lying well-established states ${B}_{1}(5721)$, ${B}_{2}^{*}(5747)$, ${B}_{s1}(5830)$ and ${B}_{s2}^{*}(5840)$, we give a quark model classification for the high mass resonances observed in recent years. It is found that (i) the ${B}_{J}(5840)$ resonance may be explained as the low mass mixed state $B(|SD{⟩}_{L})$ via $2{^{3}S}_{1}\ensuremath{-}1{^{3}D}_{1}$ mixing, or the pure $B(2{^{3}S}_{1})$ state, or $B(2{^{1}S}_{0})$. (ii) The ${B}_{J}(5970)$ resonance may be assigned as the $1{^{3}D}_{3}$ state in the $B$ meson family, although it as a pure $2{^{3}S}_{1}$ state cannot be excluded. (iii) The narrow structure around 6064 MeV observed in the ${B}^{+}{K}^{\ensuremath{-}}$ mass spectrum at LHCb may be mainly caused by the ${B}_{sJ}(6109)$ resonance decaying into ${B}^{*+}{K}^{\ensuremath{-}}$, and favors the assignment of the high mass $1D$-wave mixed state ${B}_{s}(1{D}_{2}^{\ensuremath{'}})$ with ${J}^{P}={2}^{\ensuremath{-}}$, although it as the $1{^{3}D}_{3}$ state cannot be excluded. (iv) The relatively broader ${B}_{sJ}(6114)$ structure observed at LHCb may be explained with the mixed state ${B}_{s}(|SD{⟩}_{H})$ via $2{^{3}S}_{1}\ensuremath{-}1{^{3}D}_{1}$ mixing, or a pure $1{^{3}D}_{1}$ state. Most of the missing $1P$-, $1D$-, and $2S$-wave $B$- and ${B}_{s}$-meson states have a relatively narrow width, they are most likely to be observed in their dominant decay channels with a larger data sample at LHCb.