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Neutrino o scillation physics II

Neutrino o scillation physics II. Alberto Gago PUCP CTEQ-FERMILAB School 2012 Lima, Perú - PUCP. Oscillation in matter. When neutrinos go through matter they can suffer coherent forward elastic scattering ( e.g its four momentum is unchanged) which modifies the mixing angle .

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Neutrino o scillation physics II

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  1. Neutrino oscillationphysics II Alberto Gago PUCP CTEQ-FERMILAB School 2012 Lima, Perú - PUCP

  2. Oscillation in matter • When neutrinos go through matter they can suffer coherent forward elastic scattering (e.g its four momentum is unchanged) which modifies the mixing angle. L. Wolfenstein, Phys. Rev. D 17, 2369 (1978); ibid. D 20, 2634 (1979) S. P. Mikheyev, A. YuSmirnov, Sov. J. Nucl. Phys. 42 (1986) 913. Neutrino interactions Theinelastic and absorption neutrino Interactions are negligible . They produce a mean free path of theorder of

  3. Oscillation in matter The low-energy charged current hamiltonianis given by: We can rearrangethisusingFierzidentities If we average out the electron current in a medium of electrons we have Since the electrons of the medium are non-relativistic, unpolarized and isotropically distributed only the electron density term survives.

  4. Oscillations in matter • Then :

  5. Oscillation in matter • Sincethematterpotentialis a time likecomponent: Similar tothevacuumpart

  6. Oscillation in matter • Thevacuumhamiltonian:

  7. Oscillation in matter Evolutionequation in matter

  8. Oscillation in matter • From: • Wehaveforconstantdensity: Evolutionequation in the diagonal basis

  9. Oscillation in matter • Wegetfor a constantdensity: Vacuumangle Mixingangle in matter

  10. Oscillation in matter • Similar form to the vacuum oscillation formula for 2:

  11. Oscillation in matter MSW effect

  12. Cos2q=0.38 Oscillation in matter Matter suppresion We can deduce the sign of Dm2

  13. Oscillation in matter • For varying density the evolution equation is described by: Non – diagonal hamiltonian

  14. Oscillation in matter • Adiabatic regime: slow varying density

  15. Oscillations in matter The survival probability in the adiabatic case is: Fastoscillations -(averagedout) largesource-detector distance production detection

  16. Oscillations in matter • Non- adiabatic regime: fast varying density Within an interval around the resonance.

  17. Oscillation in matter • Crossingprobability:

  18. Oscillation in matter • Thesurvivalprobabilityisgivenby: LowEnergy (adiabatic) High Energy(adiabatic) Mattereffects can be neglected Mattereffects are important

  19. Oscillation in matter Howthisprobability looks like: Keeponmindthisplot!

  20. Three neutrino scheme The 3 frameworkwithinthe experimental context: Solar & reactors LBL & atms Reactor & atms * mainlysensitive

  21. Solar neutrinos Solar net reaction CNO-chain pp - chain

  22. Solar neutrino problem Objective of thefirst solar neutrino experiment Todemonstratethatthe Solar Standard model wascorrect Borexino

  23. Solution to the solar neutrino problem SNO ( D2O phase) observes: Charged current Neutral current nxe→nxe Measurement of the solar neutrino flux compatible with the SSM Thisconfirmsthat neutrinos suffer a flavourconversion

  24. Solar neutrinos Borexino Do yourememberthisprobabilityplot? ..MSW transition vacuumdominated Matterdominated Bythewaythesurvivalprobability in 3

  25. Solar neutrinos Reactor-experiments: KamLAND 53 reactors disappearance

  26. Atmospheric neutrinos

  27. Atmospheric neutrinos Theatmosphericneutrino anomalywasfoundtryingtounderstandthebackgroundinvolved in nucleondecaysearches ThentheSuper-Kamiokandeexperiment cameintothegame and…

  28. Atmospheric neutrinos ….observed in 1998 neutrino oscillations No oscillationshypothesis

  29. Long-Baseline experiments(LBL) Disappearance experiments The MINOS experiment The K2K experiment

  30. Long-Baseline experiments(LBL) MINOS experiment K2K experiment No oscillations hep-ex/0606032 No oscillations R. Nichol -Neutrino 2012

  31. Why we believe in neutrino oscillation due to mass? Oscillation maxima OscillationpatterndependsonL/E (not a minordetail in theconfirmation of oscillationduetomass)

  32. Searchesfor -LBL T2K T. Nakaya – Neutrino 2012

  33. Results of T2K MINOS R. Nichol Neutrino 2012 T. Nakaya - Neutrino 2012 This term explains the periodic behaviour in 

  34. Search for • Reactors : Source of 2013 coincidence Similar detection concept in KamLAND E. Lisi France Korea China

  35. Results of - Reno 4.9s signalsignificance FD-8% deficit ND-1.8% deficit Only rates Soo-Bong Kim – Neutrino 2012

  36. Results of - Double Chooz Rates + Shape depletion M. Ishitsuka – Neutrino 2012

  37. Results of - Daya Bay No oscillation >8s fromnullhyp. deficit D. Dwyer- Neutrino 2012 Only rates

  38. Global analysis-3 Normal Hierarchy Degeneracy in Inverted Hierarchy Fogli et. Al. Neutrino 2012

  39. Global analysis-3

  40. Global analysis-3 Precision era arxiv: 1205.5254 G.L. Fogli, E. Lisi, A, Marrone, D. Montanino, A. Palazzo, A. M. Rotunno

  41. LSND anomaly LSND anomaly (muon decay at rest)

  42. LSND anomaly There are various experimental results that constrained the LSND signal : LSND Allowed region negative results

  43. Hints for sterile neutrinos Reactor anomaly : New estimation of flux producedby beta decayfromthefissionproducts of Mention et al 1101.2755 Reactor anomaly

  44. Hints for sterile neutrinos • MiniBooNE: tension C. Polly -Neutrino 2012

  45. Hints for sterile neutrino MiniBooNE neutrino vs antineutrino data MiniBooNE vs LSND antineutrino C. Polly -Neutrino 2012

  46. Sterile neutrino schemes 3+1 3+2 Thesteriledoesnotfeelthe SM interactions

  47. Sterile neutrino 3+1 • Short Baselineexperimentoscillationprobability formula: Onlyoneoscillation frequencyispresent two neutrino system

  48. Sterile neutrino 3+1 • In particular for :

  49. Sterile neutrino 3+1-global analysis T. Schwetz -Neutrino 2012 excluded excluded Consistencybetweenappearance vs disappearance data P=10-5

  50. Sterile neutrino 3+2 analysis Thereisalsotensionin 3+2 betweendisappearance and appearancebounds. Giunti, Laveder, 1109.4033

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