Searching for Pseudo-Dirac neutrinos from Astrophysical sources in IceCube data

We analyze IceCube public data from its IC86 configuration, namely PSTracks event selection, to search for pseudo-Dirac signatures in high-energy neutrinos from astrophysical sources. Neutrino flux from astrophysical sources is reduced in the pseudo-Dirac scenario due to conversion of active-to-sterile neutrinos as compared to the neutrino oscillation scenario of only three active neutrinos over astrophysical distances. We fit IceCube data using astrophysical flux models for three point-like sources in both scenarios and constrain the active-sterile mass-square-difference in the absence of any evidence for pseudo-Dirac scenario. We find that a common mass-squared-difference δ m² for all three flavors can be constrained as δ m² 4 × 10⁻¹⁹~eV² for the source NGC 1068, δ m² 8 × 10⁻²⁰~eV² for the source TXS 0506+056, and δ m² 2.3 × 10⁻²¹~eV² for the source PKS 1424+240 at 90% C.L. A stacking analysis gives a constrain on δ m² ≤ 2.3 × 10⁻²¹~eV² at 90% CL which is dominated by the constraint obtained from PKS 1424+240.