Neutrino Mixing/Oscillation/Leptonic CP Violation, Baryogenesis

FPCP04Oct. 4-9 Daegu, Korea

Sin Kyu Kang (Seoul National University)

ContentsEvidence for Neutrino Oscillation Atmospheric Neutrino Solar Neutrino Terrestrial Neutrino Phenomenology of Neutrino Mixing Proposals of small neutrino masses Lepton Flavor & CP Violation Leptogenesis

Evidence for Neutrino Oscillations

Atmospheric Neutrino Oscillation SK observed flux deficit

SK observed an apparent oscillation dip.Rival hypotheses such as neutrino decay and decoherence disfavored !!There is also a hint of an oscillation dip in K2KSK Collab. hep-ex/0404034SK : L/E Dependence

neutrino2004

Oscillation Analysis Results L/E Oscillation Analysis Result

Solar Neutrino OscillationSNO Experiment solar neutrino observation via

CCNCES

SNO Pure D2O Results (SNO Collab. PRL 89 (2002) ) SNO Salt Fluxes(SNO Collab. PRL92 (2004) ) Fcc(ne) = 1.76 (stat.) (syst.) 106

Fes(nx) = 2.39 (stat.) (syst.) 106

Fnc(nx) = 5.09 (stat.) (syst.) 106

Fcc(ne) = 1.70 (stat.) (syst.) 106 Fes(nx) = 2.13 (stat.) (syst.) 106 Fnc(nx) = 4.90 (stat.) (syst.) 106

Evidence for flux deficit of solar neutrinoThis anomaly can be interpreted by MSW LMA

1st result From Mar. 4 to Oct.6, 2002145.1 live days, 162 ton-year ex.Neutrino disappearence at 99.99%

2nd resultFrom Mar.9 (02) to Jan 11 (04)515.1 live days, 766.3 ton-y ex.Neutrino disappearence at 99.99%

Reactor Long Baseline Experiment150 - 210 km( Epr > 2.6 MeV )ne + p e+ + n--

Solar + KamLAND

(K. Inoue, NOW04)

SummarySNO D2O data+ SKSNO salt phase Evidence for in KamLAND Evidence for oscillation in vacuum Confirm LMA solution

L/E analysis in SK Evidence for oscillation

For : Talk by T.Kobayashi nmntnen mRemarkable Progress since 2001Solar+KamLAND (Maltoni et al.04)Atm+K2K (Maltoni et al. 04)

Three Neutrino OscillationssmallMasseigenstateWeak eigenstatem1m2m3n3n2n1Neutrino MixingN.H.LBL (future)ReactorSolarKamLANDAtmosphericLBLCP phase

factory

Absolute Scale of MassFrom the oscillation result

From

WMAP

Bi-large mixing between neighboring families (1,2) & (2,3)The ratio

no strong mass hierarchy

Mixing between remote (1,3) families small ??

Absolute mass scale

Type of mass spectrum

Type of mass hierarchyWhat is the origin of neutrino mass ?Why are neutrino masses so small?Why is the lepton flavor mixing large and so different from quark mixing?Does the result of lepton mixing imply GUT ?Are neutrinos Dirac or Majorana?If new light sterile neutrinos exist, what is their nature and underlying physics?Is leptonic CP violated?Can neutrinos play a role in generating our Universe?Non-oscillating phenomenaKnown & UnknownTheoretical Questions

Nonstandard interactions (Guzzo, Holanda, Peres 04 ; Friedland, Lunardini, Pena-Garay 04) Very small flavor universality violation can lead to suppression of ve earth regeneration shift of resonance layer in the sun

Sterile neutrino mixing (Holanda & Smirnov 03 ; Dev & Kumar 04)Upturn of the solar neutrino sepctrum at low energy Homestake lower rate of Ar-production No apparent upturn of boron neutrino spectrum explained if a light sterile neutrino exists cf.) fit to solar data : (Bahcall, Gonzalez-Garcia, Pena-Garay 04) further : Strumia (hep-ph/0407132) Marandella (hep-ph.0405090)Probing subleading effects

Magnetic moment possible via magnetic moment when neutrinos pass through the magnetic field (spin-flavor precession)

Allowing in the solar neutrino flux measured at SNO, (Kang & CS Kim) PLB584(2004)

Deviation of from 1 evidence for SFP

From two set of SNO salt phase data

Indication of the existence of SFPHow large neutrino magnetic moment? experimental bound : (hep-ex/0402015)

(1) Deviations from bi-maximal mixing (Giunti & Tanimoto, 02 Frampton, Petcov, Rodejohann 04)

For In the case of small using data :

In the case of using data : Pattern of neutrino mixing

(2) Quark-Lepton Complementary (Grand Unification) (Ramond et al.03, Minakata & Smirnov 04, Raidal, Frampton & Mohapatra 04)

Simplest Higgs structure which relates quark & lepton Yukawa matrices:

In models where Md is symmetric,

(3) tri/bi-maximal mixing Harrison, Perkins, Scott 99,02 Z.Xing,02, He, Zee, 03, Koide 03 Chang, Kang, Kim 04, Kang 04

Origin of tri/bi-maximal mixing S3 permutation family symmetry

Flavor Symmetry & neutrino massesDo the patterns of neutrino masses and mixing reflect certain symmetry? This symmetry supports an inverted mass hierarchy, but rather large mee shows strong violation of this symmetry. Discrete symmetries : A4, S3, Zn, D4 (poster by Kaneko) U(1) : Froggatt-Nielsen context Non-abelian symmetries : SU(2), SO(3), SU(3)

Generation of neutrino mass : Dirac type : demands RH components (EW singlet), but their masses are unportected by symmetry Majorana type : due to neutrality

Simplest possibility : seesaw mechanism (Yanagida, Gell-mann,Ramond, Slansky,Mohapatra, Senjanivic,80)

cf) type II seesaw : introducing SU(2) triplet Higgs (Mohapatra & Senjanovic, 81, Wetterich 81)Implications of Seesaw : Neutrino Majorana : can lead to and other processes Scale of M : roughly speaking could be the indication of grand unificationWhy ?Mass eigenvalues ~

directly : to observe heavy RH neutrinos difficult!indirectly : (1) and other processes (2) Leptogenesis : probing Dirac Yukawa structure. it leads to bounds on lightest M & effective parameter determining the washout effect. (3) RH neutrinos generate renormalization effect between M and GUT scale which modifies masses and mixing of light neutrinos (4) If SUSY is realized, Yukawa couplings via RG give contributions to slepton mass matrix which in turn produces a number of observable effects via LFV How to Probe seesaw ?

(2) Radiative mechanism : Zee model : excluded in its minimal version no RH beutrino, new scalar (Frampton etal.02, X. He 04) Two loop generations : (Babu 88, Chang & Zee 00) no RH neutrino, new singlet scalar SUSY with trilinear R-parity violating couplings (Hall & Suzuki, Dree et al.)

(3) Interesting attempts in extra dimensions large EXD (ADD) :Dirac mass suppressed by the large volume of EXD (Dienes et al 98, ADD02) warped EXD (RS) : RH neutrinos can be zero modes localized on the hidden brane leading to small Dirac mass (Grossman & Neubert 00)

(4) Combination of Seesaw & radiative generations : (Hall & Suzuki, Hempfuling,Joshipura & Novakowski, Chun et al, Chun & Kang, Jung et al., Kong, Hirsch et al. Valle, Grossman & Haber, Losada & Davidson) in SUSY with tri/bi-linear R-parity violating terms tree neutrino mass generated from the seesaw due to mixing of neutrinos with neutralinos 1-loop mass via tri-linear couplings

Probing in Future Collider ExperimentsSUSY without R-parity as a theory of massive neutrinos can be testable in collider ! (Chun et al, 99,02,04, Bartl et al.03, Hirsch et al., 01,02,03) Key idea : Probing of decays of LSP (lightest SUSY particle)

Decay amplitude

Dirac CP violation : CKM-like phase in UPMNS measurable in neutrino oscillation if using the hierarchy

with (-) sign for the golden channel

and should be large should not be too small CPV phase should be large the baseline should be long enough (typically 3000 or 7000km)

Leptonic CP violationDirac CP violationConditions for observing CPV effects

IIn matter : matter effect violates CP & CPT ( & ) in matter with costant density :

(takamura et al.)How to measure ? Reactor Experiments Super Beam : JHF & SK ~300km neutrino factories ~3000, 7000km NuMI ~ 800km

Majorana CP violation : Majorana phases in UPMNS neutrino oscillations are not sensitive to those phases amplitude of : sensitive but depends on the type of mass hierarchy

Best sensitivity : Heidelberg-Moscow experiment. Recently, claim for a positive signal at > 3 sigma: (H. Klapdor-Kleingrothaus et al. PLB586(2004)) || = (0.1-0.9) eV (99.73% CL)

Future projects : sensitivity to achieve (0.01-0.05) eVMajorana CP violation

(Bilenky et al. 01, Pascoli & Petcov 04)Normal hierarchy:

Inverted hierarchy neglecting

Quasi-degenerate

Experimental errors on the parameters & uncertianties of nuclear matrix elements Difficult to determine if CP is violated in lepton sector due to Majorana CP phases. (Barger et al. , Pascoli & Petcov04)

However, it is possible if (Pascoli & Petcov 04) experimental error on a large value of aa uncertainty in nuclear matrix elements,

Method of LUT is complementary to the direct measurement of CPV

For present maximally allowed |Ue3| & maximal CPV a precision better than 10% in measurments of the sides of the LUT will allow us to establish CPV at 3 sigma (Farzan & Smirnov)Leptonic Unitary Triangle (Frazan & Smirnov 02)

Leptonic CP violation in SUSY seesaw In a basis where the charged leptons and heavy neutrinos both have real and diagonal mass matrices,The Dirac neutrino Yukawa matrix

XCKM-type matrices (a) governs leptogenesis depends on 3 CP phases (Dirac & Majorana phases)

(b) yields Mixing and CPV in the slepton sector thus, CPV in charged LFV processes arises only from 1 CKM-type phase ( RG effects ) (Borzumati, Masiero 86, Ellis et al.Hisano et al.02)

ObservablesIn a leading-logarithmic approximation,

Leptonic electric dipole moment : (see also poster by G.Cho)

contributions to EDM ~ (Ellis,Hisano,Raidal,Shimizu02)

CP violation from slepton oscillation (Arkani-Hamed et al.97) observation of sizable CPV signal would imply a definit structure for the slepton mass matrices and have strong implications for models of flavor and SUSY breaking.

From CMB acoustic peaks(WMAP)+Large Scale Structure

A Baryon Asymmetry can be generated in an expanding universe if ( Sakharov) the particle interactions violate B, C & CP the evolution of the universe out of equilibrium

Those conditions fullfiled in the CP violating, out of equilibrium decays of Ni generating L asymmetryL asymmetry B asymmetryBaryon Asymmetry via LeptogenesisLeptogenesis (Fukugita & Yanagida 86)

(Buchmuller et al.,Bari) interference between tree level and (vertex+self energy) 1-loop diagrams:

barring RH neutrino degeneracy & strong phase cancellations:

Maximum for fully herarchical neutrinosCP asymmetry

(Davidson & Ibarra 02, Buchmuller et al.)The evolution of particle number densities in the early universe determined by solving Boltzmann equationThe final B asymmetry :

From the condition :

For

Lower bound on lightest heavy neutrino mass

Requirement ,

the domain for shirnks to zero yields upper limits on mi

Contours of constant for the indicated values of in the plane (for NH) (Buchmuller et al. 02)Upper bound on light neutrino masses :

Leptogenesis in SUSYGravitino problem BBN constraints on the abundance of gravitino for 0.1 ~ 1 TeV yield the bound (Kawasaki et al.04)

incompatible with bound from leptogenesis !!

To avoid gravitino problem: Non-thermal leptogenesis(Giudice et al. Asaka , Kawasaki et al.) Heavy gravitino scenarioanomaly mediation (Ibe et al.04) Gravitino LSP scenario Alternatives to avoid :Soft Leptogenesis : using soft breaking terms as source of L-violations which do not lead to seesaw neutrino masses (Grossman et al., Dambrosio et al., Boubekeur et al., Allahverdi et al., E.J.Chun)Resonant Leptogenesis (Pilaftsis) L-asymmetry is resonantly enhanced through the mixing of nearly degenerate heavy Majorana neutrinos (~TeV)Various models for Low Scale Leptogenesis

Connection bewteen low energy CP violation and leptogenesisIn minimal seesaw with two heavy Majorana neutrinos (Glashow, Frampton, Yanagida)

mD contains 3 phases(Endo,Kaneko,Kang,Morozumi,Tanimoto) PRL89(2002)Existence of a correlationbetween

The present neutrino experiments indicate the strong evidence for massive neutrinos new physics beyond SM

Small but finite neutrino masses need drastic idea to understand it

Neutrinos may be responsible for our existence

Neutrino era is just beginning and we have long way to go..

Summary

Neutrino mass & flavor spectra

normal inverted

Neutrino Mixing

U : Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrixFor unitary matrix Mixing angles : n 2, 3, 4

CP Phases : n 2, 3, 4 Dirac : 0 1 3 Majorana : Mass Spectrum & Mixingnenmntn1n1n2n2n3n3