Determining $\alpha_s(m_Z)$ from the Heavy Jet Mass distribution

We present a state-of-the-art analysis on determining the strong coupling constant $\alpha_s(m_Z)$ from available $e^+e^-$ data for the Heavy Jet Mass (HJM) distribution. Dijet resummation is supplemented with additional resummation of shoulder logarithms appearing around the symmetric 3-jet configuration of the HJM spectrum. In addition to $\alpha_s(m_Z)$ we further obtain numerical results for two non-perturbative parameters, $\Omega_1^{\rho}$ and $\Theta_1$, encompassing effects from dijet and trijet hadronization effects, respectively.