Mixing angle between ${}^3{P}_1$ and ${}^1{P}_1$ in HQET

Some claim that there are two independent mixing angles ($\theta = 35.3^\circ$,$-54.7^\circ$)between$^3P_1$and$^1P_1$ states of heavy-light mesons in heavy quark symmetric limit, and others claim there is only one ($\theta ={35.3}^{\circ }$). We clarify the difference between these two and suggest which should be adopted. General arguments on the mixing angle between ${}^3{L}_L$ and ${}^1{L}_L$ of heavy-light mesons are given in HQET and a general relation is derived in heavy quark mass limit as well as that including the first order correction in $1\mathrm{/}{m}_Q$.