Neutrino flavor ratios from cosmic accelerators on the Hillas plot

Neutrino flavor ratios from cosmic accelerators on the Hillas plot

NOW 2010September 4-11, 2010Conca Specchiulla (Otranto, Lecce, Italy)

Walter WinterUniversität Würzburg

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Contents

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

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From Fermi shock acceleration to production

Example: Active galaxy(Halzen, Venice 2009)

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Often used: (1232)-resonance approximation

Limitations:- No - production; cannot predict / - ratio- High energy processes affect spectral shape- Low energy processes (t-channel) enhance charged pion production Charged pion production underestimated compared to 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, 2008

Fast, but no intermediate muons, pions (cooling cannot be included) Hümmer, Rüger, Spanier, Winter, 2010

Fast (~3000 x SOPHIA), including secondaries and accurate / - ratios; also individual contributions of different processes (allows for comparison with -resonance!)

Engine of the NeuCosmA („Neutrinos from Cosmic Accelerators“) software

Meson photoproduction

T=10 eV

from:Hümmer, Rüger, Spanier, Winter,

ApJ 721 (2010) 630

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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!) …

from: Hümmer, Rüger, Spanier, Winter, ApJ 721 (2010) 630

Kinematics ofweak decays: muon helicity!

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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!

?

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Opticallythin

to neutrons

Model summary

Hümmer, Maltoni, Winter, Yaguna, Astropart. Phys. (to appear), 2010

Dashed arrow: Steady stateBalances injection with energy losses and escape

Q(E) [GeV-1 cm-3 s-1] per time frameN(E) [GeV-1 cm-3] steady spectrum

Injection Energy losses Escape

Dashed arrows: include cooling and escape

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A typical example


=2, B=103 G, R=109.6 km

Maximum energy: e, p Cooling: charged , , K

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A typical example (2)


=2, B=103 G, R=109.6 km

cooling break

cooling break

Pile-upeffect

Pile-up effect Flavor ratio!

Slope:/2

Synchrotroncooling Spectral

split

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The Hillas plot

Hillas (necessary) condition for highest energetic cosmic rays (: acc. eff.)

Protons, 1020 eV, =1:

We interpret R and B as parameters in source frame High source Lorentz factors

relax this condition!Hillas 1984; version adopted from M. Boratav

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Astrophysical neutrino sources producecertain flavor ratios of neutrinos (e::):

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 e/ (nus+antinus added)

Flavor composition at the source(Idealized – energy independent)

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However: flavor composition is energy dependent!

(from Hümmer, Maltoni, Winter, Yaguna, 2010; see also: Kashti, Waxman, 2005; Kachelriess, Tomas, 2006, 2007; Lipari et al, 2007)

Muon beam muon damped

Undefined(mixed source)

Pion beam

Pion beam muon damped

Behaviorfor small

fluxes undefined

Typicallyn beamfor low E(from p)

Energywindow

with largeflux for

classification

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Parameter space scan

All relevant regions recovered

GRBs: in our model =4 to reproduce pion spectra; pion beam muon damped (confirms Kashti, Waxman, 2005)

Some dependence on injection index


=2

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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, …)

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Effect of flavor mixing

Basic dependencerecovered afterflavor mixing


However: mixing parameter knowledge ~ 2015 required

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In short: Glashow resonance

Glashow resonance at 6.3 PeV can identify Can be used to identify p neutrino production in

optically thin (n) sources Depends on a number of conditions, such as

Hümmer, Maltoni, Winter, Yaguna,

Astropart. Phys. (to appear), 2010

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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)

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Outlook: Magnetic field and flavor effects in GRB fluxes

Recipe:1. Reproduce WB flux

with -resonance including magnetic field effects explicitely

2. Switch on additional production modes, magnetic field effects, flavor effects (, flavor mixing)

Normalization increased by order of magnitude, shape totally different!

Implications???

Baerwald, Hümmer, Winter, to appear; see also: Murase, Nagataki, 2005; Kashti, Waxman, 2005; Lipari,

Lusignoli, Meloni, 2007

BACKUP

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Neutrino fluxes – flavor ratios

Hümmer, Maltoni, Winter, Yaguna, 2010

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Dependence on H

ümm

er, Maltoni, W

inter, Yaguna, 2010

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Neutrino propagation

Key assumption: Incoherent propagation of neutrinos

Flavor mixing: Example: For 13 =0, 12=/6, 23=/4:

NB: No CPV in flavor mixing only!But: In principle, sensitive to Re exp(-i ) ~ cos

Take into account Earth attenuation!

(see Pakvasa review, arXiv:0803.1701,

and references therein)

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Different event types

Muon tracks from Effective area dominated!(interactions do not have do be within detector)Relatively low threshold

Electromagnetic showers(cascades) from eEffective volume dominated!

Effective volume dominated Low energies (< few PeV) typically

hadronic shower ( track not separable) Higher Energies:

track separable Double-bang events Lollipop events

Glashow resonace for electron antineutrinos at 6.3 PeV (Learned, Pakvasa, 1995; Beacom et

al, hep-ph/0307025; many others)

e

e

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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!

Documents

Neutrino flavor ratios from cosmic accelerators on the Hillas plot