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Atmospheric Neutrino Fluxes

Atmospheric Neutrino Fluxes. Giles Barr XXIst International Conference on Neutrino Physics and Astrophysics Neutrino 2004 Paris. Synopsis. Section 1: Features of atmospheric neutrino fluxes Cosmic ray cascades 3D effects Fluxes, flux ratios Section 2: Systematics

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Atmospheric Neutrino Fluxes

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  1. AtmosphericNeutrino Fluxes Giles Barr XXIst International Conference on Neutrino Physics and Astrophysics Neutrino 2004 Paris

  2. Synopsis Section 1: Features of atmospheric neutrino fluxes • Cosmic ray cascades • 3D effects • Fluxes, flux ratios Section 2: Systematics • Primary fluxes • Hadron production • Other effects

  3. Section 1: Features of Atmospheric neutrino fluxes

  4. Neutrinos produced from a shower Primary cosmic ray π π • Primary cosmic ray: proton or heavier nucleus • Interacts in ~90g/cm2 • Atmosphere depth 1050 g/cm2 • Cascade • Most hadrons don’t reach ground. N N π K ν μ

  5. Through Going ν induced μ Eν (GeV) Partially C Contained

  6. Through Going ν induced μ Eν (GeV) Partially C Contained Osc Max Horizontal Osc Max Up Osc Max Down Δm2=2.5 x 10-3 eV2

  7. Through Going ν induced μ Eν (GeV) Partially C Contained 3D effects Osc Max Horizontal Osc Max Up Osc Max Down Pions Interact Vertical μ reach Earth’s surface Kaons Interact

  8. Summary of Atmospheric Neutrino Calculations

  9. Shower graphic 80km altitude Detector Earth’s surface No energy threshold

  10. Shower graphic 80km altitude Detector Earth’s surface No energy threshold

  11. dφ/d ln(E) (m-2s-1sr-1)

  12. Path length distributions From Honda et. al. astro-ph/040445 Solid 3D at Kamioka, Dashed 1D at Kamioka, Dot 3D at Soudan

  13. Azimuth angle distributionEast-West effect N E S W N N E S W N Eν>315 MeV Eν>315 MeV μ+ π+ p p π- μ-

  14. Ratios Flavour ratio NM=3D with no bending of secondaries in Earth’s mag field

  15. Section 2: Systematics

  16. Flux of primaries at top of atmosphere Primary fluxes dN/dEK /m2/s/sr/n • Protons = 75% of all nucleon fluxes • Helium = 15% of all nucleons = 60% of all nuclei. Protons Helium Primary Kinetic Energy (GeV/n)

  17. Residuals: Oldest measurements (Data-Fit)/Fit 100%

  18. Residuals: Newer measurements (Data-Fit)/Fit 100%

  19. Residuals: Newest measurements (Data-Fit)/Fit 100%

  20. Effect on neutrino fluxes This includes helium uncertainty shown on next slide (Data-Fit)/Fit 100%

  21. Helium Fluxes (Data-Fit)/Fit 100%

  22. 10 Daughter energy 1 TeV 100 10 1 GeV 1 GeV 10 100 1 TeV 10 Parent energy Population of hadron-production phase-space for pA →πX interactions. νμflux (represented by boxes) as a function of the parent and daughter energies. Measurements. 1-2 pT points 3-5 pT points >5 pT points Can attempt fit all the data simultaneously. Antiproton example: Duperray, Huang, Protasov, Buénerd astro-ph/0305274 Hadron production measurements SPY Atherton et. al. Barton et. al. Serpukov Allaby et. al. Eichten et. al. Cho et. al. Abbott et. al.

  23. MC comparison Hadron production: Muon fluxes (Sea level muon fluxes) x p From:Wentz et al PRD 67 073020 (2003) Corsika models Eν (GeV)

  24. Associative production • Effect of a 15% reduction in ΛK+ production

  25. Future hadron-production experiments HARP 3-15 GeV at CERN PS MIPP 5-120 GeV at FNAL MI NA49 100,160 GeV at SPS

  26. Cross section change Effect of artificial increase in total cross section of 15%

  27. Other effects:AtmosphericDensity

  28. Other effects:Magnetic field • (negligible, but perhaps include a plot from Favier et. al.) Latitude From: Favier, Kossakowski and Vialle. PRD 68 093006 (2003) Method A: Generate far from Earth Earth, propagate in (Circles) Method B: Generate near earth and propagate charge- reversed out. Latitude cos(Zenith) Latitude Latitude cos(Zenith) cos(Zenith)

  29. Return to 3D: Is it important? SuperKamiokande Collaboration hep-ex/0404034

  30. Return to 3D: Is it important? SuperKamiokande Collaboration hep-ex/0404034

  31. Conclusions • Since early days of nucleon decay expts and the atmospheric neutrino ‘anomaly’: • Large increase in calculation sophistication • Much improved primary fluxes • Hadron production data still needed • 3D effects now well understood.

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