1. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 1 Atmospheric muons & neutrinos in neutrino telescopes Neutrino oscillations Muon & neutrino beams Muons & neutrinos underground

2. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 2 Atmospheric neutrinos Produced by cosmic-ray interactions –Last component of secondary cosmic radiation to be measured –Close genetic relation with muons p + A   ± (K ± ) + other hadrons  ± (K ± )   ± +  (  )  ±  e ± +  (  ) + e ( e ) e  e  p  

3. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 3 Historical context Detection of atmospheric neutrinos Markov (1960) suggests Cherenkov light in deep lake or ocean to detect atmospheric interactions for neutrino physics Greisen (1960) suggests water Cherenkov detector in deep mine as a neutrino telescope for extraterrestrial neutrinos First recorded events in deep mines with electronic detectors, 1965: CWI detector (Reines et al.); KGF detector (Menon, Miyake et al.) Stability of matter: search for proton decay, 1980’s IMB & Kamioka -- water Cherenkov detectors KGF, NUSEX, Frejus, Soudan -- iron tracking calorimeters Principal background is interactions of atmospheric neutrinos Need to calculate flux of atmospheric neutrinos Two methods for calculating atmospheric neutrinos: From muons to parent pions infer neutrinos (Markov & Zheleznykh, 1961; Perkins) From primaries to , K and  to neutrinos ( Cowsik, 1965 and most later calculations) Essential features known since 1961: Markov & Zheleznykh, Zatsepin & Kuz’min Monte Carlo calculations follow second method

4. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 4 Historical context (cont’d) Atmospheric neutrino anomaly - 1986, 1988 … IMB too few  decays (from interactions of  ) 1986 Kamioka  -like / e-like ratio too small. Neutrino oscillations first explicitly suggested in 1988 Kamioka paper IMB stopping / through-going consistent with no oscillations (1992) Hint of pathlength dependence from Kamioka, Fukuda et al., 1994 Discovery of atmospheric neutrino oscillations by S-K Super-K: “Evidence for neutrino oscillations” at Neutriino 98 Subsequent increasingly detailed analyses from Super-K:    Confirming evidence from MACRO, Soudan, K2K, MINOS Analyses based on ratios comparing to 1D calculations Compare up vs down Parallel discovery of oscillations of Solar neutrinos Homestake 1968-1995, SAGE, Gallex … chemistry counting expts. Kamioka, Super-K, SNO … higher energy with directionality e  ( ,  )

5. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 5 Atmospheric neutrino beam Cosmic-ray protons produce neutrinos in atmosphere  / e ~ 2 for E < GeV Up-down symmetric Oscillation theory: –Characteristic length (E/  m 2 ) –related to  m 2 = m 1 2 – m 2 2 –Mixing strength (sin 2 2  ) Compare 2 pathlengths –Upward: 10,000 km –Downward: 10 – 20 km P(   ) = sin 2 2  sin 2 1.27 L(km)  m 2 (eV 2 ) E (GeV) () e  e  p   Wolfenstein; Mikheyev & Smirnov

6. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 6 Classes of atmospheric events Contained (any direction) -induced  (from below) e (or  )   Contained events Plot is for Super-K but the classification is generic External events

7. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 7 Super-K atmospheric neutrino data (hep-ex/0501064) 1489day FC+PC data + 1646day upward going muon data CC e CC 

8. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 8 Atmospheric Flavor state |  ) =  i U  i | i ), where | i ) is a mass eigenstate 10 0 0 C 23 S 23 0 -S 23 C 23 C 13 0 S 13 0 1 0 -S 13 0 C 13 C 12 S 12 0 -S 12 C 12 0 0 0 1 U = “atmospheric” “solar” C 13 ~ 1 S 13 small   ,  m 2 = 2.5 x 10 -3 eV 2 maximal mixing Solar neutrinos e  { ,  },  m 2 ~ 10 -4 eV 2 large mixing 3-flavor mixing Yumiko Takenaga, ICRC2007

9. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 9 High-energy Neutrino telescopes Large volume--coarse instrumentation--high energy (> TeV) as compared to Super-K with 40% photo-cathode over 0.05 Mton

10. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 10 Detecting neutrinos in H 2 0 Proposed by Greisen, Markov in 1960 ANTARES IceCube SNO Super-K Heritage: DUMAND IMB Kamiokande

11. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 11 The neutrino landscape Prompt ee Solar  Lines show atmospheric neutrinos + antineutrinos Slope = 3.7 RPQM for prompt from charm Bugaev et al., PRD58 (1998) 054001 Slope = 2.7 Astrophysical neutrinos (WB “bound” / 2 for osc) Expected flux of relic supernova neutrinos Cosmogenic neutrinos

12. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 12 The atmosphere The atmosphere (exponential approximation) Pressure = X v = X o exp{ -h v / h o }, where h o = 6.4 km for X v < 200 g / cm 2 Density =  = -dX v / dh v = X v / h o X v ~ p =  RT  h o ~ RT and X 0 = 1030 g / cm 2

13. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 13 Cascade equations For hadronic cascades in the atmosphere X = depth into atmosphere = Interaction length d = decay length F ji ( E i,E j ) has no explicit dimension, so F  F(  ) –  = E i /E j & ∫…F(E i,E j ) dE j / E i  ∫…F(  ) d  /  2 – Small scaling violations from m i,  QCD ~ GeV, etc – Still… a remarkably useful approximation

14. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 14 Boundary conditions EAS Boundary condition for inclusive flux

15. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 15 Uncorrelated fluxes in atmosphere Example: flux of nucleons Approximate: ~ constant, Approximate: ~ constant, leading nucleon only leading nucleon only Separate X- and E-dependence; try factorized solution, N(E,X) = f (E) · g(X), f (E) ~ E –(  +1) f (E) ~ E –(  +1) Separation constant  N describes attenuation of nucleons in atmosphere

16. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 16 Nucleon fluxes in atmosphere Evaluate  N : Flux of nucleons: K fixed by primary spectrum at X = 0 N(E, X) = N(E, 0) x exp{-X/  N }

17. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 17 Comparison to proton fluxes Account for p  n CAPRICE98 (E. Mocchiutti, thesis)

18. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 18  ± in the atmosphere  decay or interaction more probable for E   = 115 GeV pion decay probability

19. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 19  ± (K ± ) in the atmosphere Low-energy limit: E  <   ~ 115 GeV

20. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 20  ± (K ± ) in the atmosphere High-energy limit: E  >   ~ 115 GeV Spectrum of decaying pions one power steeper for E  >>  

21. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 21  and  in the atmosphere To calculate spectra of  and –Multiply  (E,X) by pion decay probability –Include contribution of kaons Dominant source of neutrinos –Integrate over kinematics of    +   and K   +  –Integrate over the atmosphere (X) –Good description of data

22. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 22 2-body decays of  ± and K ±  +   + +   K +   + +    also for negative mesons  to produce anti-neutrinos In rest frame of parent  and have equal and opposite 3 momentum p CM energy of neutrino = p = |p| = E * = (M 2 –  2 ) / (2 M) CM energy of muon = p 2 +  2 = E  * = (M 2 +  2 ) / (2 M) M = mass of parent meson,  = mass of muon For both  and : E LAB =  E* +  p cos(  )

23. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 23 Momentum distributions for , K E LAB =  E* +  p cos(   )  = E M / M and assume E LAB >> M so   1 Then (E* - p) / M < E LAB / E M < (E* + p) / M because -1 < cos(   ) < 1 Also, decay is isotropic in rest frame so dn / d cos(   ) = constant But d E LAB = d cos(   ), so dn / d E LAB = constant Normalization requires exactly one  or so the normalization gives (constant) -1 = E M ( 1 – r ) where r =  2 / M 2 for both  and Note: r  = 0.572 while r K = 0.0458, an important difference !

24. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 24 Compare  and

25. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 25  and  differ only by kinematics of  ± and K ± decay

26. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 26 Spectrum-weighted moments Z ab ≡ ∫  F ab (  ) d  (  -1)

27. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 27 Interaction vs. decay X v = 100 g / cm 2 at 15 km altitude which is comparable to interaction lengths of hadrons in air Relative magnitude of i and d i = X cos  ( E /  i ) determines competition between interaction and decay

28. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 28 High-energy atmospheric neutrinos Primary cosmic-ray spectrum (nucleons) Nucleons produce pions kaons charmed hadrons that decay to neutrinos Kaons produce most  for 100 GeV < E < 100 TeV Eventually “prompt ” from charm decay dominate, ….but what energy?

29. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 29 Importance of kaons at high E Importance of kaons –main source of > 100 GeV –p  K + +  important –Charmed analog important for prompt leptons at higher energy vertical 60 degrees

30. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 30 Neutrinos from kaons Critical energies determine where spectrum changes, but A K / A  and A C / A K determine magnitudes New information from MINOS relevant to  with E > TeV

31. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 31 Electron neutrinos K +   0 e e ± ( B.R. 5% ) K L 0   ± e e ( B.R. 41% ) Kaons important for e down to ~10 GeV

32. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 32 1.27 1.37 x x TeV  + /  - with MINOS far detector 100 to 400 GeV at depth  > TeV at production Increase in charge ratio shows – p  K +  is important –Forward process – s-quark recombines with leading di-quark –Similar process for  c ? Increased contribution from kaons at high energy

33. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 33 MINOS fit ratios of Z-factors Z-factors assumed constant for E > 10 GeV Energy dependence of charge ratio comes from increasing contribution of kaons in TeV range coupled with fact that charge asymmetry is larger for kaon production than for pion production Same effect larger for  /  because kaons dominate

34. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 34 Atmospheric neutrinos – harder spectrum from kaons? AMANDA atmospheric neutrino arXiv:0902.0675v1 Re-analysis of Super-K Gonzalez-Garcia, Maltoni, Rojo JHEP 2007

35. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 35 Signature of charm:  dependence For  K < E cos(  ) <  c, conventional neutrinos ~ sec(  ), but “prompt” neutrinos independent of angle Uncertain charm component most important near the vertical

36. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 36 Neutrinos from charm Main source of atmospheric for E > ?? ?? > 20 TeV Large uncertainty in normalization! References: Gelmini, Gondolo, Varieschi PRD 67, 017301 (2003) Higher charm production: Bugaev, E. V., A. Misaki, V. A. Naumov, T. S. Sinegovskaya, S. I. Sinegovsky, and N. Takahashi, Phys. Rev. D, 58, 054001 (1998). Lower level of charm production R. Enberg, M.H. Reno & I. Sarcevic, PRD 78, 043005 (2008).

37. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 37 Charm in astrophysical sources Depends on environment –Target photon density for p   N p –Gas density for p p  p, , K, … –The same target densities determine the competition between decay and interaction for  , K  & D  Enberg, R., M. H. Reno, and I. Sarcevic, Phys. Rev. D, 79, 053006, 2009. See Elisa Resconi’s lecture, Refs to Kelner & Aharonian

38. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 38 Muons & Neutrinos underground Muon average energy loss: from Reviews of Particle Physics, Cosmic Rays Critical energy:

39. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 39  energy spectrum underground Shallow: Average relation between energy at surface and energy underground Deep:

40. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 40 High-energy, deep muons

41. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 41 Differential and integral spectrum of atmospheric muons Differential Integral Set E  =  { exp[ b X ] - 1 } in Integral flux to get depth – intensity curve Energy loss: E  (surface) = exp{ b X } · ( E  +  ) - 

42. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 42 Plot shows dN  / d l n(E  )

43. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 43 Detecting neutrinos Rate = Neutrino flux x Absorption in Earth x Neutrino cross section x Size of detector x Range of muon (for  ) –( Range favors  channel ) Probability to detect  -induced 

44. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 44 Neutrino effective area Rate: = ∫  ( E )A eff ( E ) dE Earth absorption –Starts 10-100 TeV –Biggest effect near vertical –Higher energy ’s absorbed at larger angles

45. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 45 Neutrino-induced muons

46. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 46 Atmospheric muons (shape only) Atmospheric

47. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 47 Muons in telescopes SNO at 6000 m.w.e. depth Million to 1 background to signal from above.  Use Earth as filter; look for neurtinos from below. Downward atmospheric muons Neutrino-induced muons from all directions

48. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 48 Muons in IceCube Downward atmospheric muons Neutrino-induced muons from all directions  P. Berghaus et al., ISVHECRI-08 also HE1.5 IceCube Crossover at ~85° for shallow detectors ~75° for deepest Mediterranean site

49. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 49 Atmospheric  and in IceCube Extended energy reach of km 3 detector Patrick Berkhaus, ICRC 2009 Dmitry Chirkin, ICRC 2009 Currently limited by systematics preliminary

50. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 50 Deep muons as a probe of weather in the stratosphere Barrett et al. MACRO MINOS far detector –Sudden stratospheric warmings observed IceCube –Interesting because of unique seasonal features of the upper atmosphere over Antarctica related to ozone hole Decay probability ~ T: – h 0 ~ RT pion decay probability

51. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 51

52. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 52

53. Astroteilchenphysik 2009 Tom Gaisser Cosmic rays - 2 53 Plan for completion of IceCube Currently 59 strings 18 strings in 09/10 9 strings in 10/11 Deep core: 7 normal strings 8 with 50 DOMs below dust layer