Imprints of neutrino-pair flavor conversions on nucleosynthesis in ejecta from neutron-star merger remnants

摘要

The remnant of neutron star mergers is dense in neutrinos. By employing inputs from onehydrodynamical simulation of a binary neutron star merger remnant with a black hole of 3 M_⊙ in thecenter, dimensionless spin parameter 0.8 and an accretion torus of 0.3 M_⊙, the neutrino emission propertiesare investigated as the merger remnant evolves. Initially, the local number density of ν_e is larger than that ofν_e everywhere above the remnant. Then, as the torus approaches self-regulated equilibrium, the localabundance of neutrinos overcomes that of antineutrinos in a funnel around the polar region. The regionwhere the fast pairwise flavor conversions can occur shrinks accordingly as time evolves. Still, we find thatfast flavor conversions do affect most of the neutrino-driven ejecta. Assuming that fast flavor conversionslead to flavor equilibration, a significant enhancement of nuclei with mass numbers A > 130 is found aswell as a change of the lanthanide mass fraction by more than a factor of a thousand. Our findings hinttowards a potentially relevant role of neutrino flavor oscillations for the prediction of the kilonova(macronova) light curves and motivate further work in this direction.