Atmospheric neutrino fluxes

Teresa Montaruli, Paolo Desiati, Aya Ishihara, UW, IceCube Meeting, Mar 2005

• A background and an interesting measurement• How well do we know the atmospheric neutrino fluxes?

The primary CR spectrum• Can we have a muon and neutrino flux from the same code?• A tool for simulation and analysis: a C++ class and a library

for fluxes (suitable for ANIS and IceTray)

It is a beautiful measurement with the largest data

sample AMANDA (IceCube) have since K physics and prompt

Fluxes are poorly constrained by accelerator data

Super-Kamiokande and MACRO

MACRO final dataBartol 96HKKM (2001 CR)FLUKA (2001 CR)FLUKA (1996 CR)

E>1 GeV

predictions no oscill.

~20%

Honda 2001 Honda 1995 Bartol 1996 SK Data

predictions m2=2.5 10-3eV2

SK and MACRO through-going muon data pointed out that theCR assumed after ICRC2001 by HKKM and Bartol was too steep and that a betteragreement was achieved with the previous Agrawal et al. 1996 CR flux

Moreover ATIC data preferred E-2.7 to steeper spectra

TM, ICRC2003 HE rapporteur talk

Primary CRsPrimary spectra: ICRC2001 (softer), Agrawal or Old Bartol (harder)

He

p

5% agreement between AMSand Bess98 < 100 GeVBUT CAPRICE -20%

ICRC2001 assumes AMS-BessThe region relevant for AMANDA/IceCube is higlyuncertain due to large errors of Jacee and RunJob dataMoreover He and heavy components are worse knownand their relevance increases

The inputs: primary CRs in most recent calculations

Main difference between ICRC2001/Gaisser-Honda 2002: CNO+Si-Mg+Fe E-

2.7/harderMain difference between ICRC2001/HKKM 2004: He [average of E-2.74+E-

2.64]/ E-2.64] + protons [E-2.74 / E-2.74+E-2.71 (E>100 GeV)] Results: HKKM 2004 is closer to previous Agrawal et al, 1996, harder than ICRC2001 and Gaisser-Honda fit resulting in more through-going muons

Gaisser-Honda 2002

Theoretical ErrorsThough HKKM 2004 uses a harder spectrum than Bartol, it is lower!

Interaction models are different (Target 2/DPMJET-III – to be updated 15%

lower than L3 data)

Lots of comparisons between Bartol, HKKM and FLUKA groups resulted in

uncertainty reduction also thanks to muon data in the atmosphere.

These groups published their results in 2003-2004.

Can AMANDA data help?

How does Lipari flux (used in AMANDA) compare to the more recent

calculations?

These results agree with: Gaisser astro-ph/0502380

hep-ex/0501064

AMANDA works in a higher E region where oscillations play a small role BUT in the region where hadronic models are worsely known(K physics, prompts…)

Systematics need to be reduced – Paolo’s talk!!!!

AMANDA DATA

SK data prefer higher fluxes by 12% and harder spectra than HKKM2004 +0.05>100 GeV

Atmospheric s and s with FLUKAFLUKA (http://www.fluka.org) new runs extending up to 106

GeV/nucleon started at UW. The goal is to have neutrinos from 4 and

atmospheric muons from the same interaction and transport code

(first 3D code, Astr.Phys.19, 2003)

Prompt neutrinos and muons will be addressed when DPMJET-III

interface will be ready

FLUKA yet poorstatistics

L3 datacan helpreducingsystm at HE

The inputs: primary CR for VHE spectrum

NEW FLUKA generation: CR suitable for VHE

The AtmosphericFlux Class• The constructor: AtmosphericFlux mymodel(model);• Class Methods: Init: Read Tables in prepared in common format Flux: returns the flux at a given energy, angle and for a flavor eg: double flux = mymodel.Flux(1,1.e3,0.1); returns: flux in GeV-1 cm-2 sr-1 s-1 given: • Neutrino type: e, anti-e, , anti-

• Neutrino Energy• Cos(zenith) Average flux: returns averaged over lower hemisphere

Compatible with ANISUsable by IceTray (A. Hishihara)Usable in analysis stage with ROOT as a shareable libraryExtensible to ANY FLUX (can become a library of fluxes to

be used for event reweighting purposes)