The pp interactions taking place in the cosmos around us are a source of the astrophysical neutrinos of all the three flavors. In these interactions, the electron and the muon neutrinos mainly come from the production and the decay of the π± mesons, whereas the tau neutrinos mainly come from the production and the decay of the DS± mesons. We estimate the three intrinsic neutrino flavor ratios for 1 GeV ≤ E ≤ 1012 GeV in the pp interactions and found them to be 1:2:3 × 10-5. We study the effects of neutrino oscillations on these intrinsic ratios. We point out that the three ratios become 1:1:1 if L(pc)/E(GeV) ≥ 10-10 in the presence of neutrino oscillations, where L is the distance to the astrophysical neutrino source in units of parsecs.
Bibliographical noteFunding Information:
The work of H.A. was supported by the Physics Division of NCTS. C.S.K. was supported in part by CHEP-SRC Program and in part by Grant No. R02-2003-000-10050-0 from BRP of the KOSEF. J.L. was supported in part by BK21 program of the Ministry of Education in Korea and in part by Grant No. F01-2004-000-10292-0 of KOSEF-NSFC International Collaborative Research Grant.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Astronomy and Astrophysics
- Physics and Astronomy(all)