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A. Yu. Smirnov

Neutrinos:. discovering. new physics world. A. Yu. Smirnov. International Centre for Theoretical Physics, Trieste, Italy Institute for Nuclear Research, RAS, Moscow, Russia. Ljubljana, January 9, 2008. Neutrinos:. - elusive, - very small, extremely light. fermions spin 1/2.

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A. Yu. Smirnov

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  1. Neutrinos: discovering new physics world A. Yu. Smirnov International Centre for Theoretical Physics, Trieste, Italy Institute for Nuclear Research, RAS, Moscow, Russia Ljubljana, January 9, 2008

  2. Neutrinos: • - elusive, • - very small, • extremely light fermions spin 1/2 Qg = 0 Qc = 0 Only the weak and gravitational interactions unique feature - neutrality: r < 10-16 cm Enormous and largely unexplored potential for applications Key tool in our understanding micro as well as macro world Particular role in nature • - one of the most abundant • component in the Universe; • related to the Dark energy? Construction of the Standard model and beyond

  3. ... new physics world Since 1998 Discovery of neutrino mass and mixing Applications Underlying physics

  4. Discovery of neutrino masses and mixing

  5. Neutrino masses Kinematical methods It took more than 70 years since … 106 105 104 103 102 101 100 10-1 10 -2 me Pauli W. Pauli’s original idea 1930: ``…of the order of electron mass’’ Fermi E. Fermi’s estimations, 1934: m < 0.1 me mn , eV Bergkvist ITEP Zurich Los Alamos Troitzk, Mainz to conclude: KATRIN at least one neutrino mass is in the range (0.05 – 0.20) eV Work of several generations of theoreticians and experimentalists 2008 ~ 10-7 me , ~ 10-10 mp , ~10-12mt

  6. 50 years ago... B. Pontecorvo ``Mesonium and antimesonium’’ Zh. Eksp.Teor. Fiz. 33, 549 (1957) [Sov. Phys. JETP 6, 429 (1957)] translation mentioned a possibility of neutrino mixing and oscillations Results of Wu experiment, 1957: Parity violation  V-A theory, two-component massless neutrino Oscillations imply non-zero masses (mass squared differences) and mixing

  7. Neutrino mixing Mass eigenstates Flavor neutrino states: n1 n2 n3 nm nt ne m1 m2 m3 m e t - correspond to certain charged leptons Mixing - interact in pairs • flavor –characteristic • of interaction Flavor states Mass eigenstates = n  p + e- + ne nf = UPMNSnmass p  m + nm

  8. Mixing angles ne nm nt |Ue3|2 Moduli of mixing elements are paremeterization independent |Um3|2 |Ut3|2 n3 tan2q12 =|Ue2|2 / |Ue1|2 Dm2atm sin2q13 = |Ue3|2 mass |Ue2|2 n2 tan2q23 = |Um3|2 / |Ut3|2 n1 Dm2sun |Ue1|2 Normal mass hierarchy Rotation in 3D space nf = UPMNSnmass Dm2atm = Dm232 = m23 - m22 UPMNS = U23 Id U13 I-d U12 Dm2sun = Dm221 = m22 - m21

  9. Solar KamLAND neutrinos Atmospheric Masses MINOS neutrinos Mixing K2K CHOOZ Cosmology Double beta decay MiniBooNE Supernova neutrinos Beta decay

  10. Determination of parameters Oscillations in vacuum and in matter Mass and mixing parameters Modification of neutrino properties (flavors) Dmij2 = mi2 - mj2 qij Adiabatic conversion in matter - the MSW effect Measurements Two effects of neutrino propagation

  11. Oscillations Periodic (in time and distance) process of transformation (partial or complete) of one neutrino species into another one ne nm ne nm ne nm ne 1.0 0.5 survival probability 0 distance Occurs in vacuum or in medium with constant density

  12. Refraction L. Wolfenstein, 1978 for ne nm ne e Elastic forward scattering Potentials Ve, Vm W V ~ 10-13 eV inside the Earth for E = 10 MeV ne e difference of potentials Ve- Vm = 2 GFne Refraction index: n - 1 = V / p ~ 10-20 inside the Earth < 10-18 inside the Sun n – 1 = ~ 10-6 inside the neutron star Neutrino optics

  13. Adiabatic conversion - the MSW - effect Medium with slowly varying density survival probability distance Flavor of neutrino state follows density change

  14. Solar Neutrinos 4p + 2e- 4He + 2ne + 26.73 MeV electron neutrinos are produced Adiabatic conversion F = 6 1010 cm-2 c-1 total flux at the Earth n Oscillations in matter of the Earth r : (150 0) g/cc

  15. Homestake GNO SAGE GALLEX Kamiokande

  16. SuperKamiokande 50 kt water Cherenkov detector n e -> ne SNO Detect effect of adiabatic conversion

  17. BOREXINO 7Be neutrinos, E = 0.862 MeV 300t n e -> ne 47.5 live days fiducial mass 87.9 t (liquid scintillator) rate: 47 +/- 7 (st) +/-12(syst) count/(day 100ton)

  18. KamLAND Kamioka Large Anti-Neutrino Detector Reactor long baseline experiment 150 - 210 km ne + p e+ + n Epr > 2.6 MeV Data: total rate energy spectrum of events Vacuum oscillations Detection of the Geo-neutrinos Epr > 1.3 MeV 1 kton of Liquid scintillator

  19. Atmospheric neutrinos Parametric effects in nm - ne oscillations for core crossing trajectories ne atmosphere p p m nm N e cosmic rays nm nm - ne oscillations in matter n core At low energies: r = Fm /Fe = 2 nm - nt vacuum oscillations n mantle Detector SuperKamikande Soudan MACRO, MINOS

  20. K2K KEK to Kamioka nm -> nm Vacuum oscillations SuperKamiokande

  21. MINOS Main Injector Neutrino Oscillation Search LBL: Fermilab – SOUDAN mine Near detector (1km): 1 kton Far detector (735 km) 5400 t, steel, sampling calorimeter Beam: 120 GeV protons 2.5 1020 p/year -> 1 - 10 GeV neutrinos Vacuum oscillations

  22. Cosmological bounds Large scale structure of the Universe SDSS

  23. Double beta decay Heidelberg-Moscow experiment 76Ge  76Se + e + e neutrinoless double beta decay Fifth detector Evidence of the effect Cosmology? If 2b 0n mechanism?

  24. Spectrum ne nm nt ? n3 n2 Dm2sun n1 ? mass mass Dm2atm Dm2atm n2 Dm2sun n1 n3 Inverted mass hierarchy Normal mass hierarchy • - 1-3 mixing • mass hierarchy • CP violation phase • absolute scale of neutrino mass • additional neutrino states Unknown: nf = UPMNSnmass UPMNS = U23 Id U13 I-d U12

  25. Leptons versus quarks zero 1-3 mixing? ? n3 t maximal mixing mass mass tri-maximal n2 c n1 u large 1-2 mixing Quarks Leptons small mixing nf = UPMNSnmass Ud = UCKM+ U U = (u, c, t) combination of upper-quarks produced with a given down quark

  26. What is behind? Understanding the results

  27. Salient features: Small Strange related? neutrino mixing pattern masses New symmetries? indicate that most probably we are touching something qualitatively new

  28. Comments: Physics behind neutrino mass and mixing is not yet identified Something beyond the standard model Data show both order and some degree of randomness  no simple explanations is expected Different pieces of data testify for different underlying physics and illustrations

  29. On cross-roads

  30. Main line 1. Smallness of neutrino mass is related to the Majorana nature of neutrinos P. Minkowski T. Yanagida M. Gell-Mann, P. Ramond, R. Slansky S. L. Glashow R.N. Mohapatra, G. Senjanovic Majorana: neutrino = antineutrino allowed by neutrality of neutrinos mn 2. See-saw scenario n mD (normal)2 Large MR small = N small = masses of usual neutrinos normal = electroweak scale ~ 100 GeV Large = masses of ``Right’’ neutrino or some VEV The same mechanism explains large lepton mixing?

  31. Grand unification? RH neutrino components have large Majorana mass 1 MR mn = - mDT mD in the presence of mixing MGUT MR ~ MGUT2 MPl MGUT ~ 1016 GeV - possible scale of unification of EM , strong and weak interactions Neutrino mass as an evidence of Grand Unification ? •  lepton asymmetry • baryon asymmetry of the Universe Leptogenesis: the CP-violating out of equilibrium decay N  l + H

  32. Scales of new physics Grand Low scale unification mechanisms Planck M3 ~ MGUT Intermediate EW scale? scale kev-scale mechanisms? scale With many O(100) RH neutrinos 1019 GeV 1016 GeV 10-6 GeV 1010 GeV 25 orders of magnitude!

  33. Quark-Lepton Complementarity ``Lepton mixing = bi-maximal mixing – quark mixing’’ A.S. M. Raidal H. Minakata ql12 + k qq12 ~ p/4 ql23 + qq23 ~ p/4 k = 2-1/2 or 1 qualitatively: 2-3 leptonic mixing is close to maximal because 2-3 quark mixing is small 1-2 leptonic mixing deviates from maximal substantially because 1-2 quark mixing is relatively large

  34. Possible implications ``Lepton mixing = bi-maximal mixing – quark mixing’’ Quark-lepton symmetry unification Existence of structure which produces bi-maximal mixing See-saw? Properties of the RH neutrinos Vquarks = I, Vleptons =Vbm m1 = m2 = 0 In the lowest approximation:

  35. Tri/bimaximal mixing L. Wolfenstein P. F. Harrison D. H. Perkins W. G. Scott 2/3 1/3 0 - 1/6 1/3 1/2 1/6 - 1/3 1/2 Utbm = n3 is bi-maximally mixed n2is tri-maximally mixed - maximal 2-3 mixing - zero 1-3 mixing - no CP-violation sin2q12= 1/3 Utbm = U23(p/4)U12

  36. Possible implications Utbm = Umag U13(p/4) E. Ma 1 1 1 Umag = 1 w w2 1 w2 w w = exp (-2ip/3) tetrahedron Symmetry: symmetry group of even permutations of 4 elements A4 representations: 3, 1, 1’, 1’’ Other possibilities: T7 , D4 , S4 ,D(3n2 ) … Relation to masses? No analogy in the quark sector? Unification is problematic? Extended higgs sector, Auxiliary symmetries, vacuum alignment

  37. 1-2 mixing QLCl p/4 -qC tbm QLCn KamLADN + SNO, 2007 Maltoni et al 2007 3s 2s 3s SNO (2n) 2s 1s Strumia-Vissani 99% 90% Fogli et al 3s Gonzalez-Garcia, Maltoni 1s q12 29 31 33 35 37 39 q12+ qC ~p/4 UQLC1 = UC Ubm Utbm = Utm Um13 give almost same 12 mixing

  38. Real or accidental? Tri-bimaximal mixing Q-L-complementarity Maximal 2-3 mixing Small 1-3 mixing Koide relation From numerology to fundamental principles?

  39. Something completely different? Extra Dimensions New mechanism of generation of small Dirac masses: overlap suppression Related to the fact that the right-handed components of neutrinos have no SM interactions

  40. ...in large flat extra D Small Dirac masses due to ``overlap suppression’’ 3D brane Mass term: m fL fR + h. c. If left and right components are localized differently in extra dimensions  suppression: fL wave functions m e fL fR + h. c. overlap fR amount of overlap in extra D Arkani-Hamed, Dvali, Dimopoulos 0 R Large extra D + 3D brane RH neutrinos propagate in the bulk A Yu Smirnov

  41. ...in warped extra D Grossman Neubert Huber, Shafi... Visible brane Hidden brane In Randall -Sundrum (non-factorizable metric) fR0 fL0 Setting: 1 extra D S 1/Z2 wave functions overlap p 0 f RH neutrinos - bulk zero mode localized on the hidden brane A Yu Smirnov

  42. ... on the fat brane Arkani-Hamed, Schmaltz 3D brane fR fR wave functions overlap fL fL A Yu Smirnov

  43. What's next? New measurements: type of spectrum (quasi-degenerate hierarchical), type of hierarchy, majorana nature; 1-3 mixing, deviation of 2-3 mixing from maximal, CP-violation phases; tests of predictions of particular models… This may discriminate various possibilities but not lead to final answer. LHC, other non-neutrino experiments may check low scale models, mechanisms, test a context Theory: two points of view Nothing fundamental – accidental interplay of many unrelated factors; results of some complicated evolution (like planetary system?) The hope is that neutrinos will uncover something simple and illuminating before we will be lost in the string landscape

  44. Applications Toward neutrino technologies

  45. The earth density profile A.M. Dziewonski D.L Anderson 1981 PREM model Fe inner core Si outer core (phase transitions in silicate minerals) transition zone lower mantle crust upper mantle liquid solid

  46. The earth portraits ne nt’ - peaks; - ridges; - valleys; - saddle points zenith angle oscillograms: E. Akhmedov M. Maltoni, A.S, Contours of constant oscillation probability

  47. Measuring oscillograms Goals: Study of various oscillation effects e.g. parametric enhancement of oscillations Determination of neutrino parameters: - 1-3 mixing - mass hierarchy: normal vs. inverted - CP – violation phase Tomography of the Earth resolution: 4pE/Dm2 > 100 km Tools: Accelerator Atmospheric beams neutrinos E ~ 0.5 -- few GeV, 10 – 30 GeV cos qn < 0.3 fixed E ~ 0.1 – 104 GeV, cos qn = -1 -- 0 Detectors: > 1 Mt TITAND? Superbeams, beta beams muon factories

  48. Supernovae: monitoring shock wave 20 years SN1987A Diffusion Flavor conversion inside the star Propagation in vacuum Oscillations Inside the Earth

  49. Shock wave effects R.C. Schirato, G.M. Fuller, astro-ph/0205390 Influences neutrino conversion if sin2q13 > 10-5 Adiabaticity breaking in shock wave front  Adiabaticy violation wave. Time - energy The effects are in the neutrino (antineutrino) for normal (inverted) hierarchy: h - resonance change the number of events ``wave of softening of spectrum’’ delayed Earth matter effect Density profile with shock wave propagation at various times post-bounce

  50. Shock wave effects Window of broken adiabaticity R. Tomas, et al., JCAP 0409, 015 2004 time – energy connection Average energy of events at SK Antineutrino survival probability at different moments of time In window spectrum change H  MS

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