A Few Notes on Non-perturbative Parameters in Heavy Quark Expansion

Non-perturbative parameters to the order $\mathcal{O}(\frac{1}{m_Q})$ in HQET expansion, $\bar{\mathrm{\Lambda }}$, ${\lambda }_1$ and ${\lambda }_2$, as well as the masses, $m_b$ and $m_c$, are estimated phenomenologically from $B$ and $D$ meson system spectroscopy. We found relatively large value of $m_b$ and quite small value of $\bar{\mathrm{\Lambda }}$ compared to previous estimates.