Searching for pseudo-dirac neutrinos from astrophysical sources in IceCube data

Abstract 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 the 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 four point-like sources in both scenarios and constrain the active-sterile mass-square-difference in the absence of any evidence for the pseudo-Dirac scenario. We present the exclusion regions for the common mass-squared difference $$\delta m^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>δ</mml:mi> <mml:msup> <mml:mi>m</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> , inducing active-sterile oscillations, for all three neutrino flavors. This includes results from individual sources as well as from a stacking analysis that combines data from the four sources. Our findings indicate that the exclusion region is $$\delta m^2 \in [2.1\times 10^{-21} - 2.0\times 10^{-16}]$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>δ</mml:mi> <mml:msup> <mml:mi>m</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo>∈</mml:mo> <mml:mrow> <mml:mo>[</mml:mo> <mml:mn>2.1</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>21</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:mn>2.0</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>16</mml:mn> </mml:mrow> </mml:msup> <mml:mo>]</mml:mo> </mml:mrow> </mml:mrow> </mml:math> eV $$^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>2</mml:mn> </mml:mmultiscripts> </mml:math> with $$\ge 90\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>≥</mml:mo> <mml:mn>90</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> confidence level (CL) significance for neutrino energies ranging from 0.5 TeV to 1 PeV. When we extend the energy range down to 0.1 TeV, the exclusion region broadens to $$\delta m^2 \in [1.1 \times 10^{-21} - 3.0\times 10^{-16}]$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>δ</mml:mi> <mml:msup> <mml:mi>m</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo>∈</mml:mo> <mml:mrow> <mml:mo>[</mml:mo> <mml:mn>1.1</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>21</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:mn>3.0</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>16</mml:mn> </mml:mrow> </mml:msup> <mml:mo>]</mml:mo> </mml:mrow> </mml:mrow> </mml:math> eV $$^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>2</mml:mn> </mml:mmultiscripts> </mml:math> at $$\ge 90\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>≥</mml:mo> <mml:mn>90</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> CL.