Where are the higher excited $B$ and $B_s$ mesons with coupled-channel effects?

Abstract

Inspired by the newly observed $B_{s0}^{\ast }(5700{)}^0$, whose mass agrees well with our previous unquenched prediction for $B_s(1^3{P}_0)$ [Phys.~Rev.~D \textbf{109}, 116006 (2024)], we study the mass spectra and OZI-allowed two-body strong decays of the higher $3S$-, $2P$-, $2D$-, and $1F$-wave $B$ and $B_s$ mesons in the same unquenched quark model. Our results show that coupled-channel effects significantly lower the masses and modify the relative level spacings. The scalar state $B(2^3{P}_0)$ is strongly affected: its mass is lowered well below the quenched quark model predictions, and it mainly decays into $B\pi$. Furthermore, the mass ordering of the vector states $B(2^3{D}_1)$ and $B(3^3{S}_1)$ is reversed, and the lighter $B(2^3{D}_1)$ state mainly decays into $B_1(5721)\pi$. To test these results, the $B(2^3{P}_0)$ and $B(2^3{D}_1)$ states are worth searching for in the $B\pi$ and $B_1(5721)\pi$ channels, respectively. In addition, some higher excitations are predicted to be relatively narrow and can be searched for in the $B^{(\ast )}\pi$, $B^{(\ast )}K$, $B_1(5721)\pi /K$, and $B_2^{\ast }(5747)\pi /K$ channels. These predictions provide useful references for future experimental searches and help clarify the role of coupled-channel effects in the heavy-light meson spectrum.

arXiv comment12 pages, 2 figures, 9 tables