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 –Primary fluxes –Hadron production –Other effects
Section 1: Features of Atmospheric neutrino fluxes
Neutrinos produced from a shower Primary cosmic ray: proton or heavier nucleus Interacts in ~90g/cm 2 Atmosphere depth 1050 g/cm 2 Cascade Most hadrons don’t reach ground. Primary cosmic ray N N K π π μ ν π
E ν (GeV) Contained Partially C Through Going ν induced μ
E ν (GeV) Osc Max Down Osc Max Horizontal Osc Max Up Contained Partially C Through Going ν induced μ Δm 2 =2.5 x eV 2
Vertical μ reach Earth’s surface Pions Interact Kaons Interact 3D effects E ν (GeV) Osc Max Down Osc Max Horizontal Osc Max Up Contained Partially C Through Going ν induced μ
Summary of Atmospheric Neutrino Calculations Zatsepin, Kuz’minSP JETP 14:1294(1961)1D E. V. Bugaev and V. A. Naumov,PL B232:391 (1989)1D Agrawal, Gaisser, Lipari, StanevPRD 53:1314 (1996)1DTarget D. PerkinsAsp.Phys. 2:249 (1994)Mu Honda, Kajita, Kasahara, MidorikawaPRD 52:4985 (1995)1DFRITIOF Battistoni et alAsp.Phys 12:315 (2000) Asp.Phys 19:269 (2003) 3DFLUKA P. LipariAsp.Phys 14:171 (2000)3D V. Plyaskin PL B516:213 (2001) hep-ph/ D GHEISHA Tserkovnyak et alAsp.Phys 18:449 (2003)3D CALOR-FRITIOF GFLUKA/GHEISHA Wentz et alPRD (2003)3D Corsika: DPMJET VENUS, UrQMD Liu, Derome, BuénerdPRD (2003)3D Favier, Kossalsowski, ViallePRD (2003)3DGFLUKA Barr, Gaisser, Lipari, Robbins, StanevPRD (July 2004)3DTarget Honda, Kajita, Kasahara, MidorikawaPRD (2001) PRD submitted (2004) 3DDPMJET
Shower graphic Detector No energy threshold 80km altitude Earth’s surface
Shower graphic Detector No energy threshold 80km altitude Earth’s surface
dφ/d ln(E) (m -2 s -1 sr -1 )
Path length distributions From Honda et. al. astro-ph/ Solid 3D at Kamioka, Dashed 1D at Kamioka, Dot 3D at Soudan
Azimuth angle distribution East-West effect NESWNNESWN E ν >315 MeV p p π+π+ π-π- μ+μ+ μ-μ-
Ratios Flavour ratio NM=3D with no bending of secondaries in Earth’s mag field
Section 2: Systematics
Primary fluxes Protons = 75% of all nucleon fluxes Helium = 15% of all nucleons = 60% of all nuclei. αKbc H He CNO Ne-Si Fe(56) Primary Kinetic Energy (GeV/n) dN/dE K /m 2 /s/sr/n Protons Helium Flux of primaries at top of atmosphere
Residuals: Oldest measurements (Data-Fit)/Fit 100%
Residuals: Newer measurements (Data-Fit)/Fit 100%
Residuals: Newest measurements (Data-Fit)/Fit 100%
Effect on neutrino fluxes (Data-Fit)/Fit 100% This includes helium uncertainty shown on next slide
Helium Fluxes (Data-Fit)/Fit 100%
Barton et. al. Atherton et. al. SPY Serpukov Allaby et. al. Abbott et. al. Eichten et. al. Cho et. al. 1 GeV TeV Parent energy 10 Population of hadron- production phase-space for pA → πX interactions. ν μ flux (represented by boxes) as a function of the parent and daughter energies. Measurements. 1-2 p T points 3-5 p T points >5 p T points Can attempt fit all the data simultaneously. Antiproton example: Duperray, Huang, Protasov, Buénerd astro-ph/ GeV TeV 10 Daughter energy Hadron production measurements
Hadron production: From: Wentz et al PRD (2003) Corsika models (Sea level muon fluxes) x p E ν (GeV) Muon fluxes MC comparison
Associative production Effect of a 15% reduction in ΛK + production
Future hadron- production experiments HARP 3-15 GeV at CERN PS MIPP GeV at FNAL MI NA49 100,160 GeV at SPS
Cross section change Effect of artificial increase in total cross section of 15%
Other effects: Atmospheric Density
Other effects: Magnetic field (negligible, but perhaps include a plot from Favier et. al.) From: Favier, Kossakowski and Vialle. PRD (2003) Method A: Generate far from Earth Earth, propagate in (Circles) Method B: Generate near earth and propagate charge- reversed out. Latitude cos(Zenith)
Return to 3D: Is it important? SuperKamiokande Collaboration hep-ex/ D bigger >30% 10%-30% 3%-10% <3% 1D bigger 3%-10% 10%-30%
SuperKamiokande Collaboration hep-ex/ D bigger >30% 10%-30% 3%-10% <3% 1D bigger 3%-10% 10%-30% Return to 3D: Is it important?
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.