  Using two cold-neutron triple-axis spectrometers we have succeeded in fully
mapping out the field-dependent evolution of the non-reciprocal magnon
dispersion relations in all magnetic phases of MnSi. The non-reciprocal nature
of the dispersion manifests itself in a full asymmetry (non-reciprocity) of the
dynamical structure factor $S(q, E, \mu_0 H_{int})$ with respect to flipping
either the direction of the applied magnetic field $\mu_0 H_{int}$, the reduced
momentum transfer $q$, or the energy transfer $E$.
