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Neutrino o scillation physics

Neutrino o scillation physics. Alberto Gago PUCP CTEQ-FERMILAB School 2012 Lima, Perú - PUCP. Outline. Introduction Neutrino oscillation in vacuum Neutrino oscillation in matter Review of neutrino oscillation data Conclusions. Historical introduction .

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Neutrino o scillation physics

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

  2. Outline • Introduction • Neutrino oscillation in vacuum • Neutrino oscillation in matter • Review of neutrino oscillation data • Conclusions

  3. Historicalintroduction (1930) W. Pauli propose a new particleforsavingtheincompatibilitybetweentheobservedelectronenergyspectrum and theexpected. Observed Spectrum – Continuos three body decay Expected Spectrum-Monoenergetic two body decay

  4. Historical introduction  (1956)- F. Reines y C.Cowan detected for the first time a neutrino through the reaction This search was called as poltergeist project. (1962)-Lederman-Schwartz-Steinberger, discovered in Brookhaventhe muon antineutrino throughthereaction: theydidnot observe: Confirmingthat First reactor neutrino experiment First neutrino experimentthatused

  5. Historical introduction  (2000) In Fermilabthe DONUT collaborationobservedforthefirst time events of  . Theydetectedfourevents.

  6. Neutrinos Active neutrinos

  7. Neutrinos -SM Therefore in theStandard Model (SM) wehave: Left-handeddoublet Neutrinos are fermions and neutrals Only neutrinos of twokindshavebeenseen in nature: left-handed –neutrino right-handed- antineutrinos

  8. Neutrino –SM In the SM the neutrinos are considermassless (ad-hoc assumption) ….BUT weknowthattheyhave non-zeromasses becausethey can changeflavouroroscillate …

  9. Neutrino oscillations -history (1962) Maki, Nakagawa and Sakataproposedthe mixing

  10. Neutrino oscillation in vacuum Flavourconversion Non-diagonal Theflavour (weak) eigenstates are coherentsuperpositionof themasseigenstates

  11. Neutrino mixing • Themixingmatrixisappearing in thechargedcurrentinteraction of the SM : analogtothe quark mixing case PMNS=Pontecorvo-Maki-Nakagawa-Sakata D= down quarks U= up quarks

  12. Neutrino oscillation in vacuumthescheme Flavourstates Flavourstates Detector Source Propagation Masseigenstates Coherentsuperposition of the masseigenstates Theflavourconversionhappens at longdistances!

  13. Neutrino oscillation in vacuum • Startingpoint: • Evolvingthemasseigenstates in time and position (Plane wave approximation):

  14. Neutrino oscillation in vacuum Analyzing: We are usingL instead of x

  15. Neutrino oscillation in vacuum constantterm oscillatingterm Validifthereis no sterileneutrinos Oscillation wavelength

  16. Neutrino oscillation in vacuum

  17. Neutrino oscillation in vacuum • Forthe antineutrino case: This is the only difference…we will return to this later

  18. Two neutrino oscillation

  19. Two neutrino oscillation I In thetwo neutrino frameworkwehave:

  20. Two neutrino oscillation • Introducing units to L and E

  21. Oscillation regimes • Oscillationstarting • Ideal case • Fastoscillations No oscillation

  22. Oscillation regimes Long distance Ideal distance Short distance Fixed E

  23. Sensitivity plot a sensitivity b c Not sensitivity lower probability limit for having a positive signal in a detector

  24. Exclusion plot excluded upper limit of the oscillation probability allowed

  25. Positive signal 0.001< P< 0.005 0.05 < P< 0.15 ⟨L/E⟩ = 18km/GeV ⟨L/E⟩ = 1km/GeV

  26. The mixing matrix

  27. The mixing matrix

  28. Themixingmatrix • If neutrinos are equalthan antineutrinos Chargeconjugationoperator

  29. 3-massscheme InvertedHierarchy Normal Hierarchy

  30. Themixingmatrix in 3 scheme Dirac CP phase Majorana phases …Tomorrowwewillseethecurrentmeasurements of theseanglesdone bytheexperiments

  31. Majoranaphases and neutrino oscillations Only the dirac phase is observable in neutrino oscillation

  32. CP violation

  33. CP violation • What does CP mean in neutrino oscillation ?:

  34. CP violation Jarlskog invariant Independent of the mixing matrix parameterization =rephasing invariant

  35. CP violation CP violation phase All the mixing angles have to be non-zero to have CP violated. In particular we just found out that

  36. CP violation • Itisinterestingto note that : • Checkingfor CPT

  37. Useful approximations • In thethree neutrino frameworkwehave: • Case 1 : sensitivetothelargescale : • Case 2: sensitivetothesmallscale

  38. Useful approximations • Case 1: sensitive to the large scale Similar structure to the two generation formula

  39. Useful approximations • Case 1: sensitive to the large scale Explicit formulas

  40. Useful approximations • Case 2: sensitive to the small scale averagedout Similar structureforthetwogeneration formula

  41. Useful approximations • Case 2: sensitivetothesmallscale Approximation Full Probability

  42. Usefulapproximations • We can get a betterapproximationfortheoscillation formula whenweexpandthis in smallparameters up tosecondorder. We are in the case of sensitivity of thelargescale. • Thesesmallparameters are : leadingterm –P2approximation Nowitisappearing  and

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