Neutrinos as Probes of new Physics Manfred Lindner Max-Planck-Institut für Kernphysik, Heidelberg
The Birth of the Neutrino energy-momentum conservation: postulate new particle invisible, since Q=0 spin ½,... W. Pauli: Letter to DPG meeting in Tübingen happy 80 th birthday" Electron undetectable! 2
New Physics: Neutrino Sources Sun Cosmology Atmosphere Astronomy: Supernovae GRBs UHE ν s Reactors Accelerators Earth β-sources 3
Physics Beyond the Standard Model QED QCD SM" U(1) em SU(3) C SU(3) C x SU(2) L x U(1) Y" Success story of d=4 renormalizable " QFTs" Theoretical reasons for BSM: SM does not exist without cutoff (triviality) Higgs-doublett = only simplest extension Gauge hierarchy problem Gauge unification, charge quantization Strong CP problem Unification with gravity Why: 3 generations, which representations Many parameters (9+? masses, 4+? mixings) TOE solving all problems does not (yet) exist solve some problems increasing levels of speculation: 1) new fields 2) extend gauge group 3) new concepts (SUSY,...) 4) wild speculations Experimental BSM facts: Electro weak scale << Planck scale Gauge couplings almost unify Neutrinos have masses & large mixings Baryon asymetry of the Universe Dark Matter, Dark Energy, few > 2σ hints? BSM from a neutrino perspective neutrino masses discovered" M. Lindner Recontres de Blois, June 2011 4
Fermion Masses in the Standard Model QM relativistic QM: Schrödinger Dirac eqn." Ψ = (Ψ 1,Ψ 2,Ψ 3,Ψ 4 ) = Ψ L + Ψ R = L + R ; L/R = P L/R Ψ Fermion Mass terms: _" _" mψψ = m(l R + R L)" " mass term = L-R bridge" SM: L = doublet under SU(2) L ; R = singlet of SU(2) L" no explicit (Dirac) mass terms allowed in SM!" solution: Higgs mechanism: glφr gvlr = M L R" _" _" _" Majorana mass terms for uncharged fields: M R c R" _" 5
New Physics: Neutrino Mass Terms 1) Simplest possibility: add 3 right handed neutrino fields ν L g N ν R x <φ> = v ν R x ν R Majorana L / c c like quarks and charged leptons Dirac mass terms (including NMS mixing) New ingredients: 1) Majorana mass (explicit) 2) lepton number violation 6x6 block mass matrix see-saw M R : 3 heavy + 3 light ν s NEW ingredients, 9 parameters SM+ M. Lindner Recontres de Blois, June 2011 6
2) Maybe 3+N right handed neutrino fields (6+N) x (6+N) mass matrix how many of the 6+N eigenvalues are light (also for N=0) 3) new: scalar tripelts (3 L ) ν L ν 3" L or fermionic 1 L or 3 L x x left-handed Majorana mass term: ν L 1,3" ν L x x _ M L LL c 4) Both ν R and new singlets / triplets: see-saw type II, III m ν =M L - m D M R -1 m D T M. Lindner Recontres de Blois, June 2011 7
5) Higher dimensional operators: d=5, _ M L LL c 6) Radiative neutrino mass generation 7-N) SUSY, extra dimensions, M. Lindner Recontres de Blois, June 2011 8
Other effective Operators Beyond the SM effects beyond 3 flavours Non Standard Interactions = NSIs effective 4f opersators integrating out heavy physics (c.f. G F M W ) ν α ν β f f Grossman, Bergmann+Grossman, Ota+Sato, Honda et al., Friedland+Lunardini, Blennlow +Ohlsson+Skrotzki, Huber+Valle, Huber+Schwetz+Valle, Campanelli+Romanino, Bueno et al., Barranco+Miranda+Rashba, Kopp+ML+Ota, M. Lindner Recontres de Blois, June 2011 9
3 Light Neutrinos (...assumed) Mass & mixing parameters: m 1, Δm 2 21, Δm2 31, sign(δm2 31 ) diag(e iα, e iβ,1) questions: Dirac / Majorana ν e ν µ ν τ mass scale: m 1 mass ordering: sgn(δm 2 31 ) how small is θ 13, θ 23 maximal? leptonic CP violation 3 flavour unitarity? why 3 generations, why d=4, normal inverted hierarchical or degenerate M. Lindner Recontres de Blois, June 2011 10
Suggestive Seesaw Features QFT: natural value of mass operators scale of symmetry m D ~ electro-weak scale M R ~ L violation scale? embedding (GUTs, ) See-saw mechanism (type I) m ν =m D M R -1 m D T m h =M R Numerical hints: For m 3 ~ (Δm 2 atm )1/2, m D ~ leptons M R ~ 10 11-10 16 GeV ν s are Majorana particles, m ν probes ~ GUT scale physics! smallness of m ν high scale of L, / symmetries of m D,M R M. Lindner Recontres de Blois, June 2011 11
2nd Look Questions Quarks & charged leptons hierarchical masses neutrinos? log (m/gev) d u e ν 1 c s µ degenerate ~1eV ν 2 ν 3 hierarchical 0.05eV, 0.005eV ~0.005eV t b τ Quarks and charged leptons: m D ~ H n ; n = 0,1,2 H > 20...200 Neutrinos: m ν ~ H n H < ~10 See-saw: m ν = -m DT M R -1 m D 1. 2. 3. generation H ~10 >20? >20» less hierarchy in m D or corr. hierarchy in M R? theoretically not connected!» other version of see-saw? type II, III,?» Dirac masses? M. Lindner Recontres de Blois, June 2011 12
Overview of Neutrino Mass Knowledge neutrino mass scale <23 ev ν oscillations were observed finite mass splittings finite mass SN1987A <~0.2 ev <2.2 ev tritium endpoint Mainz & Troitsk 0νββ if neutrino is Majorana < ~0.3 ev cosmology ~ degenerate ~ 0.2 ev KATRIN? ~ 0.05 ev hierarchical different types of masses / different systematics M. Lindner Recontres de Blois, June 2011 13
Four Methods of Mass Determination kinematical lepton number violation Majorana nature astrophysics & cosmology oscillations 14
Kinematical Mass Determination Future: KATRIN 0.25 ev c.f. comological bounds 15
Four Methods of Mass Determination kinematical lepton number violation Majorana nature astrophysics & cosmology oscillations 16
Double Beta Decay: Mass Parabolas S odd-odd even-even Q 76 Zn β - 76 Ga β + 76 Rb β - 76 Br 76 Kr EC 76 Ge 76 As β - β + 76 Se normal β-decay energetically forbidden for 76 Ge double beta decay allowed even-even nuclei 30 31 32 33 34 35 36 37 Z 17
0νββ Decay Kinematics 2νββ decay of 76 Ge observed: τ =1.5 10 21 y 0νββ decay 2νββ decay Majorana ν 0νββ decay warning: other lepton number violating processes may exist signal at known Q-value 2νββ background (resulution) nuclear backgrounds use different nuclei 18
Relating Rates / Lifetimes to Neutrino Masses rate of 0νββ phase space nuclear matrix elements effectivemajorana neutrino mass 1/τ = G(Q,Z) M nucl 2 <m ee > 2 nuclear matrix elements: virtual excitations of intermediate states Fäßler et al., p p 0νββ 0 + 1 + 2 - k k k e 1 e 2 ν n n E k E i 0 + 0 + progress in TH errors reduced uncertainties 19
Neutrino-less Double β-decay ν Majorana ν 0ν2β decay - < 0.35 ev? Heidelberg-Moscow experiment free parameters: m 1, sign(δm 2 31 ), CP-phases Φ 2, Φ 3 20
Claim of part of the original Heidelberg-Moscow experiment cosmology tension aims of new experiments: test HM claim (Δm 312 ) 1/2 ~ 0.05eV + errors reach 0.01eV CUORE GERDA phases I, II, (III) Recent WMAP 5year data Comments: m 1 [ev] cosmology: limitation by systematical errors ~another factor 5? 0νββ nuclear matrix elements ~factor 1.3-2 theoretical uncertainty in m ee Δm 2 > 0 allows complete cancellation 0νββ signal not guaranteed 0νββ signal from *some other* new BSM lepton number violating operator very promising interplay of neutrino mass determinations, cosmology, LHC, LVF experiments and theory 21
GERDA filled, commissioning with non-enriched strings start of data taking with enriched Ge now!" M. Lindner Kolloquium Dresden, 21.6.2011 22
Four Methods of Mass Determination kinematical lepton number violation Majorana nature cosmology & astrophysics oscillations 23
Summary of Neutrinos & Cosmology Dark Matter ~ 22% & Dark Energy 73% mass of all neutrinos: 0.001 < Ω ν < 0.02 baryonic matter Ω Β ~ 0.04 Neutrino mass contribution: possibly as big as all baryonic matter >> visible matter much more COLD dark matter & dark energy neutrinos are still an important hot dark matter component Comological impact of neutrinos: - hot component in structure formation: 330ν/cm 3 x mass - Big Bang Nuklueosynthesis - Baryon asymmetry Leptogenesis -... 33 24
Four Methods of Mass Determination kinematical lepton number violation Majorana nature astrophysics & cosmology oscillations 25
Neutrino Oscillations ν µ ν µ Wahrscheinlichkeit P ν µ ν e" sin 2 (2θ) L osc = 4π E/Δm 2 P(ν µ ν e ) = sin 2 (2θ) sin 2 (Δm 2 x L/4E) P(ν µ ν µ ) = 1 - P(ν µ ν e ) Distanz L 26
Atmospheric Oscillations @SuperK 27
KamLAND tests solar Oscillations 26 reactors at L~180km; 80GW th = 7% of World reactor power! KamLAND flux ~1/L 2 + oscillations?" Kamioka Contribution from overseas Korea 2.46% Other countries 0.7% tests solar oscillations with reactor anti-ν s 28
Solar ν s: NC, CC, ES Rates from SNO SK ES 68% CL SNO NC 68% CL SNO CC 68% CL SNO ES 68% CL SSM 68%CL Φ CC = Φ e Φ ES = Φ e + 1/6 Φ µτ Φ NC = Φ e + Φ µ + Φ τ Clear proof of flavour conversion Independent of SSM test of SSM! No conversion and conversion to sterile ν s excluded by many sigma ~ no L/E dependence 29
Status of Neutrino Oscillations solar: GALLEX/GNO SK, SNO Reactors: KAMLAND improved result Beams: K2K MINOS OPERA described by ~ two independent 2x2 oscillations surprise: large mixings! Δm 2 21 = (7.9+0.3) * 10-5 ev 2 tan 2 θ 12 = 0.39 + 0.05 Δm 2 31 = (2.4+0.3) *10-3 ev 2 tan 2 θ 23 = 1.0 + 0.3 sin 2 2θ 13 < 0.16 Chooz atmospheric: Superkamiokande LSND? MiniBooNE - LSND not confirmed! 3+2 scenarios? new anomaly - upturn at low E? 30
Future Precision Oscillation Physics Precise measurements 3f oscillation formulae = x Majorana- CP-phases θ 23 S 13 3 flavour effects θ 12 CP phase δ Aims: improved precision of the leading 2x2 oscillations detection of generic 3-neutrino effects: θ 13, CP violation Complication: Matter effects effective parameters in matter expansion in small quantities θ 13 and a = Δm 2 sol / Δm2 atm Burguet-Castell et al., Akhmedov et al. 31
Future Precision with Reactor Experiments identical detectors many errors cancel - - - 3 flavour effect no degeneracies no correlations no matter effects E=4MeV 2km 4km 40km 80km Double Chooz Daya Bay Reno Angra clean & precise θ 13 measurments 32
Double Chooz sin 2 2θ 13 sensitivity Now - Chooz < 0.20 Double Chooz < 0.02 Triple Chooz? < 0.008 33
Double Chooz and Triple Chooz FD only sin 2 2θ 13 sensitivity Chooz limit < 0.20 Double Chooz < 0.02 Triple Chooz? < 0.008 Double Chooz! very soon operational addition of ND improving Chooz bound! 2-3 months of data 2 nd FD very promising, " especially if hints for finite sin 2 θ 13 correct " 34
Other coming Oscillation Experiments RENO in Korea Daya Bay components + NOvA construction started T2K neutrino beamline started operation luminosity M. Lindner Kolloquium Dresden, 21.6.2011 35
T2K Status 1 st T2K run (Jan.-June 2010) ~50 kw average 3.23 10 19 protons for analysis 2 nd run since mid Nov. ramp up to 115 kw Aim 150 kw 10 7 s by July 2011 10 1 st run after analysis: sensitivity to sin 2 2θ 13 0.05 @ 90%CL potential for reactor F(sin 2 2θ 13 ) / beam interplay F(sin 2 2θ 13, CP phase δ) 36 36
T2K Evidence Expected Signal in DC Last week: ~ 2.5σ evidence for finite θ 13" exciting for Double Chooz (data taking since March)" 37
θ 13 Now and in the Future MINOS OPERA Double Chooz T2K NOνA Reactor II NUE+FPD proton driver? β-beams ν factory range unknown CP phase synergies w. reactor GLoBES" 38
Conclusion Neutrinos test & constrain new physics in many ways! important information potential for surprises 39