Remarks on the $S$-wave masses of singly heavy mesons

Abstract: Based on the study of the string model methods of singly heavy mesons and singly heavy baryons, we calculate the mass spectrum of $1S$-and $2S$-wave for both charm and bottom mesons$(D/D_{s}, B/B_{s})$. Experimentally, there are most masses spectra of $1S$-wave have been found, while the masses part of the $2S$-state is not determined. In this paper, we will use singly light quark or diquark model images and Regge trajectory models, combined with perturbation processing methods, to analyze and study the observed singly heavy mesons, further predict the unobserved mesons masses and their corresponding spin-parity quantum numbers.