Given a semiconductor whose six equivalent X-valley minima occur at the Brillouin zone faces so that only half of each valley lies within the first zone. Each X-valley has "jelly-bean" shaped constant-energy surfaces with one effective mass (the longitudinal,ml*) along the long axis and equal masses (the transverse,mt*) along each of the two short axes. Find the Density of States mass associated with the X-valleys of this semiconductor.