Enhanced muonization by active-sterile neutrino mixing in protoneutron stars

We study nu mu-nu s mu- nu s and nu<overline>mu-nu<overline>s mu-nu<overline> s mixing in the protoneutron star (PNS) created in a core-collapse supernova (CCSN). We point out the importance of the feedback on the general composition of the PNS in addition to the obvious feedback on the nu mu mu lepton number. We show that for our adopted mixing parameters delta m2 similar to m 2 similar to 102 2 keV2 2 and sin2 2 2 theta consistent with the current constraints, sterile neutrino production is dominated by the Mikheyev-Smirnov-Wolfenstein conversion of nu<overline>mu mu into nu<overline>s s and that the subsequent escape of nu<overline>s s increases the nu mu mu lepton number, which in turn enhances muonization of the PNS primarily through nu mu mu + n -> p + mu-. - . While these results are qualitatively robust, their quantitative effects on the dynamics and active neutrino emission of core-collapse supernovae should be evaluated by including nu mu-nu s mu- nu s and nu<overline>mu-nu<overline>s mu-nu<overline> s mixing in the simulations.