Frontiers in Neutrino Physics

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Bruce Osborne
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1 Frontiers in Neutrino Physics Neutrinos as a Probe Spectra Intrinsic Properties Astrophysics/Cosmology/Geophysics

3 Neutrinos as a Unique Probe: cm Particle Physics νn, µn, en scattering: existence/properties of quarks, QCD Weak decays (n pe ν e, µ e ν µ ν e ): Fermi theory, parity violation, quark mixing Neutral current, Z-pole, atomic parity: electroweak unification, field theory, m t ; severe constraint on physics to TeV scale Neutrino mass: constraint on TeV physics, grand unification, superstrings, extra dimensions; seesaw: m ν m 2 q /M GUT

4 Astrophysics/Cosmology Core of Sun Supernova dynamics Atmospheric neutrinos (cosmic rays) Violent events (AGNs, GRBs, cosmic rays) Large scale structure (dark matter) Nucleosynthesis (big bang - small A; stars iron; supernova - large N) Baryogenesis Simultaneous probes of ν and astrophysics Interior of Earth

Neutrino Spectra ν Oscillations P νa ν b = sin 2 2θ sin 2 ( m 2 L 4E ) 10 0 KARMEN2 NOMAD MiniBooNE Bugey NOMAD CDHSW CHORUS NOMAD CHORUS LSND 90/99% 3 ν Patterns Solar: LMA (SNO, KamLAND, Borexino)

5 Neutrino Spectra ν Oscillations P νa ν b = sin 2 2θ sin 2 ( m 2 L 4E ) 10 0 KARMEN2 NOMAD MiniBooNE Bugey NOMAD CDHSW CHORUS NOMAD CHORUS LSND 90/99% 3 ν Patterns Solar: LMA (SNO, KamLAND, Borexino) m ev 2, mixing large but nonmaximal Atmospheric + K2K + MINOS: m 2 Atm ev 2, near-maximal mixing Reactor: U e3 small m 2 [ev 2 ] Cl 95% Ga 95% CHOOZ all solar 95% SNO 95% ν e ν X ν µ ν τ ν e ν τ ν e ν µ All limits are at 90%CL unless otherwise noted SuperK 90/99% MINOS tan 2 θ K2K KamLAND 95% Super-K 95% 10 2

6 Mixings: let ν ± 1 2 (ν µ ± ν τ ): ν 3 ν + ν 2 cos θ ν sin θ ν e ν 1 sin θ ν + cos θ ν e 3 2 m 2 m 2 atm 1 m 2 atm Normal hierarchy 2 1 m2 3 Inverted hierarchy Analogous to quarks, charged leptons ββ 0ν rate very small ββ 0ν if Majorana Degenerate pattern for m m 2

7 Outstanding Issues (intrinsic properties) Scale of underlying physics? (string, GUT, TeV?) Mechanism? (seesaw, LED, HDO, stringy instanton?) Hierarchy, U e3, leptonic CP violation? (mechanism, leptogenesis) Absolute mass scale? (cosmology) Dirac or Majorana? (mechanism, scale, leptogenesis) Baryon asymmetry? (leptogenesis, electroweak baryogenesis, other?)

8 Outstanding Issues (intrinsic properties) Scale of underlying physics? (string, GUT, TeV?) (LHC, flavor) Mechanism? (seesaw, LED, HDO, stringy instanton?)(indirect: LHC) Hierarchy, U e3, leptonic CP violation? (mechanism, leptogenesis) (long baseline, reactor, ββ 0ν, supernova) Absolute mass scale? (cosmology) (β decay, cosmology, ββ 0ν, supernova) Dirac or Majorana? (mechanism, scale, leptogenesis) (ββ 0ν ) Baryon asymmetry? (leptogenesis, electroweak baryogenesis, other?) (indirect: LHC)

9 Other properties Models ν interactions (MINERνA, SciBooNE, SNS [CLEAR], MicroBooNE, NuSOnG) Puzzles/anomalies NuTeV, MiniBooNE, GSI) Quantum subtleties Sterile ν s (OscSNS) ν decay (LSND, Electromagnetic moments Decoherence Non-standard interactions Neutrino counting Heavy ν s CPT, Lorentz, equivalence violation FCNC (associated ν, l) R P violation ν ν Mass-varying ν s Time-varying ν s ν interferometry

10 U e3, δ CP, hierarchy U = c 13 0 s 13 e iδ c 12 s 12 0 e iα c 23 s s 12 c e iα s 23 c 23 s }{{} 13 e iδ 0 c }{{}}{{}}{{} atmospheric, s s , δ=? Solar, s Majorana only Need s 13 0 for leptonic CP and hierarchy by matter effects

11 s at 90% (CHOOZ reactor ν e disappearance; global) Hints for s 13 0: MINOS (0.7σ excess from ν µ ν e?); Solar vs KamLAND Future reactor: near and far detectors (s 13 only) Double CHOOZ (France) Daya Bay (China) RENO (South Korea) Gonzalez-Garcia,Maltoni,Salvado,

12 Long Baseline (LBL) Oscillation Experiments 3 ν oscillations, small s 13 and m 2 (Akhmedov et al, JHEP 04, 078): P ν µ νe = α 2 sin 2 2θ 12 c 2 sin 2 A s 2 sin 2 (A 1) A 2 13 s2 23 (A 1) 2 where α = + 2 α s 13 sin 2θ 12 sin 2θ 23 cos( + δ) m2 m 2 Atm 0.03, δ δ and A A for P νµ ν e, A > 0 (normal),, A < 0 (inverted) sin A A sin(a 1) A 1 = m2 Atm L 4E, A = 2 2EGF n e m }{{ 2 Atm } matter In principle, determine s 13, δ, hierarchy (easier if s 13 from reactor)

experiment location L (km) major mode status K2K

Fermilab Soudan 735 ν µ, ν µ disappear running T2K

CERN Gran Sasso 730 ν µ ν τ ν τ observed NOνA

13 experiment location L (km) major mode status K2K KEK SuperK 250 ν µ disappear completed NUMI-MINOS Fermilab Soudan 735 ν µ, ν µ disappear running T2K J-PARC SuperK 295 O/A ν µ ν e first events OPERA CERN Gran Sasso 730 ν µ ν τ ν τ observed NOνA Fermilab Ash River 810 O/A ν µ ( ν µ ) ν e ( ν e ) construction

14 Reactor + LBL: s sin 2 2Θ 13 sensitivity limit NH, 90% CL sin 2 2Θ 13 discovery potential NH, 90% CL GLoBES 2009 GLoBES 2009 sin 2 2Θ 13 sensitivity reach CHOOZ Solar excluded Double Chooz T2K RENO Daya Bay NO A:Ν Ν NO A:Νonly Year sin 2 2Θ 13 discovery reach CHOOZ Solar excluded Double Chooz T2K RENO Daya Bay NO A:Ν Ν NO A:Νonly Year Huber, Lindner, Schwetz, Winter,

15 Resolution of the mass hierarchy NOνA and T2K Off-axis (narrow E) NOνA: matter effects from long baseline Begin study of!cp NUMI intensity upgrade ( kw) Compare NOvA s neutrinos to NOvA s antineutrinos Compare NOvA s neutrinos w/ matter effect to T2K s neutrinos ~w/o matter effect Possible Project X beam upgrade ( 2 MW) Hierarchy and δ indication for favorable parameters

detector (+ p decay, τ 10 34 35 yr) J-PARC to Kamioka + Korea CERN to?

16 Long Baseline Neutrino Experiment (LBNE) Fermilab to Deep Underground Science and Engineering Lab (DUSEL) (1300 km) 300 KT water or 100 KT LAr detector (+ p decay, τ yr) J-PARC to Kamioka + Korea CERN to? (LAGUNA study) Neutrino factory ( µ collider) β beams DAEδALUS (several stopped π beams)

17 Tritium β spectrum (KATRIN) m ν e ( i U 2 ei m2 i Absolute Mass Scale ) 1/2 0.2 ev Cosmology (WMAP7, SDDS, H 0 ) Σ i m i < 0.58 ev (95%) Future (Planck, ACTPol, CMBPol) Σ 0.05 ev ββ 0ν observed (m ββ 0.01 ev) inverted or degenerate

18 Dirac or Majorana: Neutrinoless Double β Decay (ββ 0ν ) nn ppe e (m ββ i U 2 ei m i) p e e p Nuclear matrix element uncertainties (Γ A nuc m ββ 2 ) W ν L m ββ ν L W Other mechanisms may dominate (e.g., SUSY R P ) HDM: τ 1/2 ( 76 Ge) m ββ ( ) ev y Cuoricino: τ 1/2 ( 130 T e) < y (90%) m ββ < ( ) ev (2σ) Future exps sensitive to ev (inverted or degenerate only) n m ee ev General theory prediction Disfavored by 0ΝΒΒ decay m IO m NO Disfavored by cosmology m ev Winter, n

19 of CUORE. The NEMO3 effort to cover as many as possible ββ nuclei thus allowing a diret check for ββ(2ν) NME elements is evident (Tab. 5). The evidence for a ββ(0ν) signal has also been claimed (and recently confirmed [29] by a small subset (KHDK) of the HDM collaboration at LNGS with T1/2 0ν = y. The result is based on a re-analysis of the HDM data. Such a claim has raised some criticism but cannot be dismissed Future out of hand. ββ On the 0ν other Experiments hand, none of the existing experiments can rule out it (fig. 2), and the only certain way to confirm or refute it is with additional sensitive experiments. In particular, next generation experiments should easily achieve this goal. Isotope T 2ν 1/2 T 0ν 1/2 Future Mass Lab (10 19 y) (10 24 y) Experiment (kg) 48 Ca ( ) > [31] CANDLES OTO Ge (150 ± 10) > 19[22] GERDA LNGS [29] > 15.7[23] MAJORANA 60 SUSEL 82 Se (9.2 ± 0.7) > 0.36 [25] SuperNEMO 100 LSM 96 Zr (2.3 ± 0.2) > [25] 100 Mo (0.71 ± 0.04) > 1.1[25] MOON OTO 116 Cd (2.8 ± 0.2) > 0.17[32] 130 Te (68 ± 12) > 2.94 CUORE 204 LNGS 136 Xe > 81[33] > 0.12[34] EXO 160 WIPP KAMLAND 200 KAMIOKA 150 Nd (0.82 ± 0.09) > [35] SNO+ 56 SNOLAB Cremonesi,

Solar neutrinos ν s and Sun MSW break observed pep/cno neutrinos Metallicity conflict (helioseismology vs optical) Subdominant effects (sterile, µ ν, interactions) Borexino, ICARUS, SNO+, LENA ee

20 Solar neutrinos ν s and Sun MSW break observed pep/cno neutrinos Metallicity conflict (helioseismology vs optical) Subdominant effects (sterile, µ ν, interactions) Borexino, ICARUS, SNO+, LENA ee Survival probability for ν e, P for LMA P ee 7 Be: Borexino 8 B: Borexino, (> 3 MeV) 8 B: Borexino (> 5 MeV) 8 B: SNO (> 4 MeV) pp: all solar ν experiments E ν [MeV]

21 Supernova neutrinos Collapse of iron core of M 8M star 99% of energy ( ergs) radiated in neutrinos Neutronization pulse: e p ν e n (ms) Bounce and expanding shock Neutrinosphere radiates ν i + ν i ( 10 s) ν e observed for SN1987A (Large Magellanic Cloud) Confirmed picture of SN dynamics Limits on m ν, µ ν, new interactions

22 Expect thousands of events for galactic SN ( yr) Detailed study of core-collapse supernova dynamics SNEWS: The SuperNova Early Warning System (hours of warning and directionality) Sensitive to obscured or failed supernovae ν hierarchy, small s 13, mass scale (MSW, collective effects, time of flight) Keep detectors running for 50 yr! Experiments becoming sensitive to diffuse SN ν s from other galaxies Table 1. Summary of neutrino detectors with supernova sensitivity. Neutrino event estimates are approximate and have a fairly large uncertainty. See reference [1] for individual detector references. Not included are are smaller detectors (e.g. reactor neutrino scintillator experiments) and detectors primarily sensitive to coherent elastic neutrino nucleus scattering. Detector Type Mass (kton) Location Events at 8.5 kpc Live period Baksan C n H 2n 0.33 Caucasus present Super-K H 2 O 32 Japan present LVD C n H 2n 1 Italy present KamLAND C n H 2n 1 Japan present MiniBooNE C n H 2n 0.7 USA present Borexino C n H 2n 0.3 Italy present IceCube Long string 0.4/PMT South Pole N/A 2007-present SNO+ C n H 2n 0.8 Canada 300 Near future HALO Pb 0.07 Canada 80 Near future Icarus Ar 0.6 Italy 230 Near future NOνA C n H 2n 15 USA 3000 Near future LBNE LAr Liquid argon 5 USA 1900 Future LBNE WC H 2 O 300 USA 78,000 Future MEMPHYS H 2 O 440 Europe 120,000 Future Hyper-K H 2 O 500 Japan 130,000 Future LENA C n H 2n 50 Europe 15,000 Future GLACIER Ar 100 Europe 38,000 Future Scholberg, J. Phys. Conf. Ser., 203,

sources (AGN, GRB) Dark matter annihilation ν spectrum,

23 Neutrinos as Cosmic Rays/Secondaries Atmospheric neutrinos IceCube (+ Deep Core) and Antares High energy sources (AGN, GRB) Dark matter annihilation ν spectrum, decay, properties Ultra HE ν interactions Cosmic ray composition

24 Geoneutrinos Energy output of Earth (30-45 TW) not well understood Radiogenic heat production: (E ν e chains) < 2.6 MeV for 238 U and 232 T h KamLAND observation Recent Borexino: consistent with observed (georeactor at core excluded) Future: SNO+, LENA Events/240p.e./252.6ton-year 8 Borexino data 7 best-fit 6 reactors ν e 5 contribution from geo-ν e background Light yield of prompt positron event [p.e.]

25 The Ultimate Challenge: Relic Neutrinos ν i, ν i decoupled at few MeV (relativistic) ν COSMIC RAY Redshifted to form of relativistic thermal distribution (T ν ( 4 11) 1/3 Tγ 1.9K, n νi 50/cm 3 ) Indirect: BBN (N ν = 3.2 ± 1.2 at z ); WMAP7+SDSS+H 0 (N ν = 4.3 ± 0.9 at z 10 3 ) D GZK ~50 Mpc Z ν RELIC } 0 10 π 20 γ 2 nucleons 17 π - + e + -,ν,ν Direct detection extraordinarily difficult (22 th century) Macroscopic forces (O(G 2 F )) or torques (O(G F )) ν-induced e ± emission by nuclei Z- burst: resonant annihilation of ultra-high energy ( ev) cosmic ν (source? flux?)

26 Conclusions Neutrino physics is extremely interesting

27 Conclusions Neutrino physics is extremely interesting Neutrino physics is extremely difficult

28 Neutrino Preliminaries Weyl fermion Minimal (two-component) fermionic degree of freedom ψ L ψr c by CPT Active Neutrino (a.k.a. ordinary, doublet) in SU(2) doublet with charged lepton normal weak interactions ν L νr c by CPT Sterile Neutrino (a.k.a. singlet, right-handed) SU(2) singlet; no interactions except by mixing, Higgs, or BSM N R NL c by CPT Almost always present: Are they light? Do they mix?

29 Dirac Mass Connects distinct Weyl spinors (usually active to sterile): (m D ν L N R + h.c.) 4 components, L = 0 I = 1 2 Higgs doublet Why small? (Large dimensions? Higherdimensional operators? String instantons?) ν L h N R v = φ m D = hv

30 Majorana Mass Connects Weyl spinor with itself: 1 2 (m T ν L νr c + h.c.) (active); 1 2 (m S N L cn R + h.c.) (sterile) 2 components, L = ±2 Active: I = 1 (triplet or higher-dimensional operator) Sterile: I = 0 (singlet or bare mass) Mixed Masses Majorana and Dirac mass terms ν L ν c R ν L ν L Seesaw for m S m D : m T M 2 D /m S Ordinary-sterile mixing for m S and m D both small and comparable

Neutrino Basics. m 2 [ev 2 ] tan 2 θ. Reference: The Standard Model and Beyond, CRC Press. Paul Langacker (IAS) LSND 90/99% SuperK 90/99% MINOS K2K

Neutrino Basics. m 2 [ev 2 ] tan 2 θ. Reference: The Standard Model and Beyond, CRC Press. Paul Langacker (IAS) LSND 90/99% SuperK 90/99% MINOS K2K Neutrino Basics CDHSW m 2 [ev 2 ] 10 0 10 3 10 6 10 9 KARMEN2 Cl 95% NOMAD MiniBooNE Ga 95% Bugey CHOOZ ν X ν µ ν τ ν τ NOMAD all solar 95% SNO 95% CHORUS NOMAD CHORUS LSND 90/99% SuperK 90/99% MINOS K2K