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Neutrino flavor ratios from cosmic accelerators on the Hillas plot

Neutrino flavor ratios from cosmic accelerators on the Hillas plot. NOW 2010 September 4-11, 2010 C onca Specchiulla (Otranto, Lecce, Italy) Walter Winter Universität Würzburg. TexPoint fonts used in EMF: A A A A A A A A. Contents. Introduction Meson photoproduction Our model

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Neutrino flavor ratios from cosmic accelerators on the Hillas plot

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  1. Neutrino flavor ratios from cosmic accelerators on the Hillas plot NOW 2010 September 4-11, 2010Conca Specchiulla (Otranto, Lecce, Italy) Walter Winter Universität Würzburg TexPoint fonts used in EMF: AAAAAAAA

  2. Contents • Introduction • Meson photoproduction • Our model • Flavor composition at source • Hillas plot and parameter space scan • Flavor ratios/flavor composition at detector • Summary

  3. From Fermi shock acceleration to n production Example: Active galaxy(Halzen, Venice 2009)

  4. Meson photoproduction • Often used: D(1232)-resonance approximation • Limitations: • No p- production; cannot predict p+/ p- ratio • High energy processes affect spectral shape • Low energy processes (t-channel) enhance charged pion production • Charged pion production underestimated compared to p0 production by factor of > 2.4 (independent of input spectra!) • Solutions: • SOPHIA: most accurate description of physicsMücke, Rachen, Engel, Protheroe, Stanev, 2000Limitations: Often slow, difficult to handle; helicity dep. muon decays! • Parameterizations based on SOPHIA • Kelner, Aharonian, 2008Fast, but no intermediate muons, pions (cooling cannot be included) • Hümmer, Rüger, Spanier, Winter, 2010Fast (~3000 x SOPHIA), including secondaries and accurate p+/ p- ratios; also individual contributions of different processes (allows for comparison with D-resonance!) • Engine of the NeuCosmA („Neutrinos from Cosmic Accelerators“) software from:Hümmer, Rüger, Spanier, Winter, ApJ 721 (2010) 630 T=10 eV

  5. NeuCosmA key ingredients • What it can do so far: • Photohadronics based on SOPHIA(Hümmer, Rüger, Spanier, Winter, 2010) • Weak decays incl. helicity dependence of muons(Lipari, Lusignoli, Meloni, 2007) • Cooling and escape • Potential applications: • Parameter space studies • Flavor ratio predictions • Time-dependent AGN simulations etc. (photohadronics) • Monte Carlo sampling of diffuse fluxes • Stacking analysis with measured target photon fields • Fits (need accurate description!) • … Kinematics ofweak decays: muon helicity! from: Hümmer, Rüger, Spanier, Winter, ApJ 721 (2010) 630

  6. A self-consistent approach • Target photon field typically: • Put in by hand (e.g. GRB stacking analysis) • Thermal target photon field • From synchrotron radiation of co-accelerated electrons/positrons • Requires few model parameters (synchtrotron cooling dominated  only overall normalization factor) • Purpose: describe wide parameter ranges with a simple model; no empirical relationships needed! ?

  7. Model summary Dashed arrows: include cooling and escape Dashed arrow: Steady stateBalances injection with energy losses and escapeQ(E) [GeV-1 cm-3 s-1] per time frameN(E) [GeV-1 cm-3] steady spectrum Opticallythinto neutrons Injection Energy losses Escape Hümmer, Maltoni, Winter, Yaguna, Astropart. Phys. (to appear), 2010

  8. A typical example a=2, B=103 G, R=109.6 km Maximum energy: e, p Cooling: charged m, p, K Hümmer, Maltoni, Winter, Yaguna, Astropart. Phys. (to appear), 2010

  9. A typical example (2) a=2, B=103 G, R=109.6 km m cooling break Synchrotroncooling Spectralsplit p cooling break Pile-up effect Flavor ratio! Pile-upeffect Slope:a/2 Hümmer, Maltoni, Winter, Yaguna, Astropart. Phys. (to appear),2010

  10. The Hillas plot • Hillas (necessary) condition for highest energetic cosmic rays (h: acc. eff.) • Protons, 1020 eV, h=1: • We interpret R and B as parameters in source frame • High source Lorentz factors G relax this condition! Hillas 1984; version adopted from M. Boratav

  11. Flavor composition at the source(Idealized – energy independent) • Astrophysical neutrino sources producecertain flavor ratios of neutrinos (ne:nm:nt): • Pion beam source (1:2:0)Standard in generic models • Muon damped source (0:1:0)at high E: Muons loose energy before they decay • Muon beam source (1:1:0)Heavy flavor decays or muons pile up at lower energies • Neutron beam source (1:0:0)Neutrino production by photo-dissociationof heavy nuclei or neutron decays • At the source: Use ratio ne/nm (nus+antinus added)

  12. However: flavor composition is energy dependent! Pion beam Muon beam muon damped Energywindowwith largeflux for classification Typicallyn beamfor low E(from pg) Pion beam muon damped Undefined(mixed source) Behaviorfor smallfluxes undefined (from Hümmer, Maltoni, Winter, Yaguna, 2010; see also: Kashti, Waxman, 2005; Kachelriess, Tomas, 2006, 2007; Lipari et al, 2007)

  13. Parameter space scan • All relevant regions recovered • GRBs: in our model a=4 to reproduce pion spectra; pion beam  muon damped (confirmsKashti, Waxman, 2005) • Some dependence on injection index a=2 Hümmer, Maltoni, Winter, Yaguna, Astropart. Phys. (to appear), 2010

  14. Flavor ratios at detector • Neutrino propagation in SM: • At the detector: define observables which • take into account the unknown flux normalization • take into account the detector properties • Example: Muon tracks to showersDo not need to differentiate between electromagnetic and hadronic showers! • Flavor ratios have recently been discussed for many particle physics applications (for flavor mixing and decay: Beacom et al 2002+2003; Farzan and Smirnov, 2002; Kachelriess, Serpico, 2005; Bhattacharjee, Gupta, 2005; Serpico, 2006; Winter, 2006; Majumar and Ghosal, 2006; Rodejohann, 2006; Xing, 2006; Meloni, Ohlsson, 2006; Blum, Nir, Waxman, 2007; Majumar, 2007; Awasthi, Choubey, 2007; Hwang, Siyeon,2007; Lipari, Lusignoli, Meloni, 2007; Pakvasa, Rodejohann, Weiler, 2007; Quigg, 2008; Maltoni, Winter, 2008; Donini, Yasuda, 2008; Choubey, Niro, Rodejohann, 2008; Xing, Zhou, 2008; Choubey, Rodejohann, 2009; Bustamante, Gago, Pena-Garay, 2010, …)

  15. Effect of flavor mixing • Basic dependencerecovered afterflavor mixing • However: mixing parameter knowledge ~ 2015 required Hümmer, Maltoni, Winter, Yaguna, Astropart. Phys. (to appear), 2010

  16. In short: Glashow resonance • Glashow resonance at 6.3 PeV can identify • Can be used to identify pg neutrino production in optically thin (n) sources • Depends on a number of conditions, such as G Hümmer, Maltoni, Winter, Yaguna, Astropart. Phys. (to appear), 2010

  17. Summary • Flavor ratios should be interpreted as energy-dependent quantities • Flavor ratios may be interesting for astrophysics: e.g. information on magnetic field strength • The flavor composition of a point source can be predicted in our model if the astrophysical parameters are known • Our model is based on the simplest set of self-consistent assumptions without any empirical relationships • Parameter space scans, such as this one, are only possible with an efficient code for photohadronic interactions, weak decays, etc.: NeuCosmA • For fits, stacking, etc. one describes real data, and therefore one needs accurate neutrino flux predictions! • References:Hümmer, Rüger, Spanier, Winter, arXiv:1002.1310 (astro-ph.HE),ApJ 721 (2010) 630Hümmer, Maltoni, Winter, Yaguna, arXiv:1007.0006 (astro-ph.HE),Astropart. Phys. (to appear)

  18. Outlook: Magnetic field and flavor effects in GRB fluxes Recipe: • Reproduce WB flux with D-resonance including magnetic field effects explicitely • Switch on additional n production modes, magnetic field effects, flavor effects (m, flavor mixing) • Normalization increased by order of magnitude, shape totally different! • Implications??? PRELIMINARY Baerwald, Hümmer, Winter, to appear; see also: Murase, Nagataki, 2005; Kashti, Waxman, 2005; Lipari, Lusignoli, Meloni, 2007

  19. BACKUP

  20. Neutrino fluxes – flavor ratios Hümmer, Maltoni, Winter, Yaguna, 2010

  21. Dependence on a Hümmer, Maltoni, Winter, Yaguna, 2010

  22. Neutrino propagation • Key assumption: Incoherent propagation of neutrinos • Flavor mixing: • Example: For q13 =0, q12=p/6, q23=p/4: • NB: No CPV in flavor mixing only!But: In principle, sensitive to Re exp(-i d) ~ cosd • Take into account Earth attenuation! (see Pakvasa review, arXiv:0803.1701, and references therein)

  23. Different event types • Muon tracks from nmEffective area dominated!(interactions do not have do be within detector)Relatively low threshold • Electromagnetic showers(cascades) from neEffective volume dominated! • nt: Effective volume dominated • Low energies (< few PeV) typically hadronic shower (nt track not separable) • Higher Energies:nt track separable • Double-bang events • Lollipop events • Glashow resonace for electron antineutrinos at 6.3 PeV t nt nt e ne m nm (Learned, Pakvasa, 1995; Beacom et al, hep-ph/0307025; many others)

  24. Flavor ratios (particle physics) • The idea: define observables which • take into account the unknown flux normalization • take into account the detector properties • Three observables with different technical issues: • Muon tracks to showers(neutrinos and antineutrinos added)Do not need to differentiate between electromagnetic and hadronic showers! • Electromagnetic to hadronic showers(neutrinos and antineutrinos added)Need to distinguish types of showers by muon content or identify double bang/lollipop events! • Glashow resonance to muon tracks(neutrinos and antineutrinos added in denominator only). Only at particular energy!

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