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					                               Moriond 2005




   On the Prospect of Tau Neutrino
Astronomy in GeV Energies and Beyond

               G.-L. Lin
     National Chiao-Tung U. Taiwan
                   Outline
• The current aspects of tau neutrino
  detections
• The reward for an effective discrimination
  of  from other neutrino flavors—
  illustrated with the detection of galactic ,
  atmospheric  background considered in
  detail.
• Conclusion
The aspects of tau neutrino detections:

   E > 106 GeV       Double bang events
                       2 showers separated by roughly
                       50(E/PeV) m

     J. G. Learned and S. Pakvasa 1995
     H. Athar, G. Parente and E. Zas 2000



   E between GeV and PeV: make use of
    shower properties
Different shower distributions for
NC and  CC+ decays T. Stanev 1999



                                Upward atmospheric ’s
                               ~100 GeV-- T. Stanev, 1999

                                 Extragalactic ’s --
                                S. I. Dutta, M. H. Reno and I. Sarcevic,
                                 2000

                              R=shower event rate/ muon event rate



   ()~() in the above.
   It will be rewarding if one can do better in discriminating
    from other flavors—in the situation () > ().
The prospect of detecting galactic : an illustration

         The Flux
       CR               Interstellar medium np=1 particle /cm3

        p  p    , K  , Ds   X ,
         Intrinsic Flux:

                                       
                 2  e     
            Due to oscillation:
              e       on Earth
         
         Athar, Jezabek and Yasuda, 2000
         Bento, Keränen and Maalampi, 2000
 Primary comic ray proton spectrum


 p E p   dN p / dE p ,   T. K. Gaisser and M. Honda, 2002


                                    
 p E p   1.49  E p  2.15  exp  0.21 E p   
                                                    2.74




 in the unit cm-2s-1sr-1GeV-1
 The flux of atmospheric background

  2-flavor oscillation analysis
                                          Y. Ashie et al. [SK Collab.], 2004
  sin 2 2 23  0.9,
  1.9 103 eV 2  m31  3 103 eV 2
                     2



  We present the results with the best fit values
       sin 2 2 23  1,
       m31  2.4 103 eV 2
         2




                          H. Athar, hep-ph/0401242
                          H. Athar, F.-F. Lee &GLL, hep-ph/0407183
                          F.-F. Lee & GLL, hep-ph/0412383
    Atmospheric  flux before Oscillations
p  A  M  X , M   , K , charm hadrons
Fraction  M    X / total .

                                  H. Athar, F.-F. Lee and GLL,
                                  hep-ph/0407183

                                           and     comparable
                                       beyond this energy
                                         from Ds decays

                                  The , K production cross
                                  Section taken from
                                  T. K. Gaisser, astro-ph/0104327

            Neutrino energy
The intrinsic tau neutrino flux can be calculated by
 perturbative QCD supplemented by models for Ds decays.

          p  A  Ds  X
          Ds    ;    X

     L. Pasquali, M. H. Reno and I. Sarcevic, 1999
 Atmospheric tau neutrino flux after oscillations

                                                       : zenith angle
                                                      cos  1, 0.8, 0.6, 0.4, 0.2, 0
                                                      From bottom to top
                                                       Downward to Horizontal
                                                       Directions, Oscillations
                                                       Occur in Atmosphere


                                           F.-F. Lee and GLL, hep-ph/0412383
               Neutrino energy

                                  dN0                        dN0
                P     
   dN
                                               1  P 
d log10 E                     d log10 E                 d log10 E 
Comparison of galactic and atmospheric ’s–
downward to horizontal directions




    =660             
              =900

 =00

                           Galactic 
                   




            Neutrino energy
F.-F. Lee and GLL, hep-ph/0412383
Comparison in the upward direction

                                     Galactic-plane observable
                                     through  for E> TeV




           Neutrino energy
                Conclusion
• We have outlined the current strategy of
  identifying astrophysical .
• We made a detailed comparison between
  galactic and atmospheric neutrino flux.
• We showed that an effective discrimination of
   from other neutrino flavors is rewarding.
  The galactic-plane can be seen through  in
  GeV to TeV energies.

				
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posted:10/16/2012
language:English
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