Forecast on lepton asymmetry from future CMB experiments
  We consider a cosmological lepton asymmetry in the form of neutrinos and
impose new expected sensitivities on such asymmetry through the degeneracy
parameter ($\xi_{\nu}$) by using some future CMB experiment configurations,
such as CORE and CMB-S4. Taking the default scenario with three neutrino
states, we find $\xi_{\mu} = 0.05 \pm 0.10 \, (\pm \, 0.04)$, from CORE
(CMB-S4) at 95 percent CL, respectively. Also, within this scenario, we
evaluate the neutrino mass scale, obtaining that the normal hierarchy mass
scheme is privileged. Our results are an update concerning on the cosmological
lepton asymmetry and the neutrino mass scale within this context, from which
can bring a perspective on the null hypothesis for $\xi_{\nu}$ (and its effects
on $\Delta N_{\rm eff}$), where perhaps, \textbf{$\xi_{\nu}$} may take a
non-null value up to 95 percent CL from future experiments such as CMB-S4.
Sensitivity results for CMB-S4 obtained here not including all expected
systematic errors.
