Use of neutrino reactions on nuclei to determine the pion dispersion relation in nuclear matter

Because of the effects of the medium on the pion dispersion relation, the lepton spectrum in the inclusive reaction $\overline{\nu }+\mathrm{nucleus}\to l^{+}+\mathrm{anything}$ will show sharp peaks due to production of a pion into the nuclear matter in the interior of the nucleus. For the case of a 420 MeV incident $\overline{\nu }$, detailed calculations show that these peaks will be far above expected backgrounds and that their observation can give a direct, point by point determination of the pion dispersion relation in nuclear matter.