Neutrino Physics Theory and Phenomenology

Size: px

Start display at page:

Download "Neutrino Physics Theory and Phenomenology"

Imogen Rose
5 years ago
Views:

1 Neutrino Physics Theory and Phenomenology Serica (Land of Silk) * Catay (Northern China) Mangi (Southern China) Sinaru[m] Situs (Chinese Land) * We are here Eligio Lisi INFN, Bari, Italy 11 th ICFA Seminar Beijing, P.R. China 014

2 Prologue: 500 years ago (A.D. ~ 1514) * Northern hemisphere We are here Southern hemisphere A remarkable world map by Leonardo da Vinci... [Royal Library, Windsor Collection. Executed by one of Leonardo s workshop assistants.]

3 Earliest known world map... A XX century octant map... made with octant projections 3

4 Earliest known world map made with octant projections... showing the name America 4

5 Earliest known world map made with octant projections... showing the name America... with America s west coast disconnected from Asia 5

6 Earliest known world map made with octant projections... showing the name America... with America s west coast disconnected from Asia... indicating a large Southern continent 6

But, A.D. 1514 too early to... a b c d b a c d.

7 But, A.D too early to... a b c d b a c d... avoid strong mapping distortions and biases 7

8 But, A.D too early to...?... avoid strong mapping distortions and biases... know about Australian continent (~ 90 years later) 8

9 But, A.D too early to Copernicus... avoid strong mapping distortions and biases... know about Australian continent (~ 90 years later)... know about a larger world picture (~ 30 years later) 9

10 500 years later......we are in a similar situation in neutrino (and particle) physics: - being excited by recent discoveries - mapping (quasi)known lands (with biases?) - planning expeditions to unknown lands - trying to find a larger world picture Theory may give some guidance in this (probably) long and difficult enterprise, largely driven by new experiments. 10

11 TALK OUTLINE: - being excited by recent discoveries - mapping (quasi)known lands (with biases?) - planning expeditions to unknown lands - trying to find a larger world picture...charting the neutrino world... 11

12 Recent discoveries: α à β oscillations in vacuum and matter eàe ( δm, θ 1 ) a µàµ ( Δm, θ 3 ) c eàe ( Δm, θ 13 ) e eàe ( δm, θ 1 ) b µàµ ( Δm, θ 3 ) d µàe ( Δm, θ 13, θ 3 ) f Data from various types of neutrino experiments: (a) solar, (b) long-baseline reactor, (c) atmospheric, (d) long-baseline accelerator, (e) short-baseline reactor, (f,g) long baseline accelerator (and, in part, atmospheric). (a) KamLAND [plot]; (b) Borexino [plot], Homestake, Super-K, SAGE, GALLEX/GNO, SNO; (c) Super-K atmosph. [plot], MACRO, MINOS etc.; (d) TK (plot), MINOS, KK; (e) Daya Bay [plot], RENO, Double Chooz; (f) TK [plot], MINOS; (g) OPERA [plot], Super-K atmospheric. See next talks by Jung, Shiozawa, Cao µàτ ( Δm, θ 3 ) g

13 Can be charted in a simple 3ν theoretical framework eàe ( δm, θ 1 ) a µàµ ( Δm, θ 3 ) c eàe ( Δm, θ 13 ) e eàe ( δm, θ 1 ) b µàµ ( Δm, θ 3 ) d µàe ( Δm, θ 13, θ 3 ) f Terra cognita: δm Δm θ 1 θ 3 θ 13 µàτ ( Δm, θ 3 ) g

14 Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix U i = c 3 s 3 0 s 3 c c 13 0 s 13 e i s 13 e i 0 c c 1 s 1 0 s 1 c e i / e i / 3 5 [ only if Majorana ] Mixing angles θ 3, θ 13, θ 1 : known CP-violat. phase(s) δ (α, β) : unknown Mass-squared spectrum (up to absolute scale) Normal Hierarchy Δm δm 1 1 δm Δm Inverted Hierarchy [ + contribution in matter ~ G F. E. density ] δm, Δm : known Matter effects (solar ν): Hierarchy : unknown 14

15 Current 3ν picture in just one slide (with 1-digit accuracy) Flavors = e µ τ Abs.scale Normal hierarchy or Inverted hierarchy mass split ν 3 m ν ν ν 1 δm +Δm -Δm Terra Cognita: ν 3 Terra Incognita: δm ~ 8 x 10-5 ev Δm ~ x 10-3 ev sin θ 1 ~ 0.3 sin θ 3 ~ 0.5 sin θ 13 ~ 0.0 δ (CP) sign(δm ) octant(θ 3 ) absolute mass scale Dirac/Majorana nature 15

systematically L5 = (LH)(LH)! L6 = QQQL, L µ 1 (LhHi)(LhHi) = m Wµ Hl, abc W aµ W b Wµc, (H Dµ H)(H Dµ H), Bµ H W µ H, 17 (H.

16 Rare effects from Old but still strong theoretical argument for Majorana ν s as messengers of high new physics scale (see-saw + Weinberg): energies Effects of high-energy physics as effective operators added to the standard model 1 1 L5 + L6 + L = LSM + can be classified systematically L5 = (LH)(LH)! L6 = QQQL, L µ 1 (LhHi)(LhHi) = m Wµ Hl, abc W aµ W b Wµc, (H Dµ H)(H Dµ H), Bµ H W µ H, 17 (H. Murayama at ICFA Seminar 011, CERN) 13 Old but still unique experimental probe of Maiorana ν s nature via ΔL= process: neutrinoless double beta decay. See next talk by Schoenert 16

17 Charting 3ν param. with more digits: global analysis à Analysis includes increasingly rich oscill. data sets: LBL Acc + Solar + KL LBL Acc + Solar + KL + SBL Reactor LBL Acc + Solar + KL + SBL Reactor + SK Atm. Parameters not shown are marginalized away. C.L. s are drawn at Δχ = 1, 4, 9 à Nσ = 1,, 3 for projections over single parameters. Figures from Capozzi et al., arxiv: (+ Neutrino 014 updates) See also: Gonzalez-Garcia et al., ; Forero et al.,

18 LBL Acc + Solar + KL + SBL Reactors + SK Atm 4 IH 3 NH Current accuracy in mapping Terra Cognita: N m -5 /10 ev m /10 NH IH ev / δm.6 % Δm.6 % sin θ % sin θ % sin θ 3 ~ 10 % * θ 3 N 1 * * π/ sin sin sin 13 (but... in which octant?) 18

19 Terra Incognita I (oscill. param.): current hints θ 3 octant N 4 3 LBL+Sol+KL +SBL Reac +SK atm unstable, fragile 1 Δχ (IH-NH) sin sin 3 3 sin negligible 4 NH NH NH δ CP N / IH IH / IH / intriguing, sin δ ~ -1 (or sin δ < 0) favored 19

20 Oscillation searches can probe the hierarchy... δm (NH) δm +Δm -Δm (IH)... if one can observe interference of oscill. driven by ±Δm with oscill. driven by another quantity Q with known sign. 3 options: Q = δm (medium-baseline reactors) Q = G F N e E (matter effects in accel./atmosph. ν) Q = G F N ν E (collective effects in SNe) All paths to the hierarchy are being actively investigated from the experimental - theoretical - phenomenological viewpoint. 0

21 The path towards a possible discovery of leptonic CP violation requires 6 steps: 3 mixing angles should be nonvanishing mass gaps should be nonvanishing 1 Dirac phase should be nonvanishing... Nature has already allowed us 5 steps in favorable conditions, i.e., at accessible terrestrial scales... Current hints suggest that the 6 th may be at reach......expeditions to neutrino CPV-land are a must! [and, if neutrinos are Majorana... CPV bonanza with more phases! ] 1

22 Let us hope that history may repeat itself, as for a previous lucky hint... Hint for Non-Zero 13 in the Current Data? G.L. Fogli et al, arxiv: [hep-ph] (A. de Gouvea at ICFA Seminar 008, SLAC) so that we may discuss about nearly maximal leptonic CP violation at ICFA seminar 0XX!

23 Terra Incognita II (absolute mass observables) (m β, m ββ, Σ) In the 3ν framework: β decay, sensitive to the effective electron neutrino mass : 0νββ decay: only if Majorana. Effective Majorana mass : Cosmology: Dominantly sensitive to sum of neutrino masses: Note 1: These observables may provide handles to distinguish NH/IH. Note : Majorana case gives a new source of CPV (unconstrained) Note : The three observables are correlated by oscillation dataà 3

24 Upper limits on m β, m ββ, Σ (up to some syst.) + osc. constraints m (ev) (ev) m (NH) (IH) m (ev) (ev) β : Mainz+Troitsk 0νββ : GERDA, EXO, KL-Zen,... Σ : CMB+LSS oscillation constraints m ββ spread due to Majorana CP phase(s): accessible in principle [Clearly, the inverted hierarchy case would make life easier...] 4

25 Upper limits on m β, m ββ, Σ in ~10 years? m (ev) (ev) m (NH) (IH) m (ev) (ev) β : KATRIN 0νββ : Upgraded/New expt. (+ NME) Σ : Precision Cosmology oscillation constraints Large phase space for discoveries about ν mass and nature. 5

26 Theory can help in both mapping and discovery expeditions Two examples of well-defined, long-term theory programs: Must improve modeling of ν-nucleus cross sections, to understand energy spectra in accelerator and atmospheric searches for CPV and mass hierarchy CCQE Benhar at NOW 014 Must improve modeling of nuclear structure, to understand and compare signals or limits on 0νββ decay rates and related weak/strong processes Simkovic at NOW 014 Require joint effort from nuclear and particle phys. communities 6

Another long-term theory program for an unpredictable event: Sooner or later (say, 10±10

.. Its autopsy will keep us busy for decades, and teach us a lot about astrophysics and

Simulations of SN explosions, (anti)nu fluences and flavor transitions, which are already

27 Another long-term theory program for an unpredictable event: Sooner or later (say, 10±10 years?), another galactic SN should explode... Its autopsy will keep us busy for decades, and teach us a lot about astrophysics and neutrino physics. Simulations of SN explosions, (anti)nu fluences and flavor transitions, which are already very demanding, will need to reach complexity levels comparable -probably- to QCD lattice calculations. SN 1054 Raffelt at NOW 014 Will spark a truly interdisciplinary program from diverse communities see also next talk by Halzen 7

28 Neutrino flavor theory: is the current picture suggestive of some simmetry? Or the symmetry is only in our mind, and there is just randomness? Are there possible connections with the quark flavor sector? ν 3 θ 1 ν ν 1 ν θ 3 θ 13 ν 1 ν 3 Many interesting ideas, but no obvious answer/guidance so far 8

Specific outcomes (a few examples from a vast literature) No organizing principle ( anarchy ) Discrete family simmetries ( geometry ) linear relations between θ 13 cosδ and θ 1, θ 3 Continuous

29 Specific outcomes (a few examples from a vast literature) No organizing principle ( anarchy ) Discrete family simmetries ( geometry ) linear relations between θ 13 cosδ and θ 1, θ 3 Continuous flavor simmetries ( dynamics ) links between neutrino spectra/angles/phases Common quark/lepton features ( complementarity ) links between θ 13 and θ C Model selection will benefit from higher precision 9

30 Beyond the 3ν paradigm? We should not be biased by the success of the 3ν scheme... If we sail too close to the 3ν coastline... we might miss an entire new continent (new neutrino states and interactions) 30

31 Light states: conflicting sightings of ν S with (sub)ev mass from various sailors in the last 0 years... new land or mirage? MiniBoone LSND ν s?! Available data: intriguing, but not conclusive or convergent. The question raised by the LSND claim is still with us: Is there ν µ àν e appearance at a scale ΔM ~O(0.1-1) ev? In recent years, further interest in light sterile ν raised by: 1) Possible associated ν e àν e disappearance signals ) Possible associated extra radiation in cosmology 31

32 [ev ] Δm GLO 68.7% CL 90.00% CL 95.45% CL 99.00% CL 99.73% CL + + sin ϑ eµ 3+1 Global Fit [Preliminary 014 Update] MiniBooNE E > 475 MeV GoF = 6% PGoF = 7% 3+1 3σ ν e DIS ν µ DIS DIS APP APP ν µ ν e & ν µ ν e : LSND (Y), MiniBooNE(?), OPERA (N), ICARUS(N), KARMEN (N), NOMAD(N), BNL-E776 (N) DIS ν e & ν e : Reactors (Y), Gallium (Y), ν e C (N), Solar (N) DIS ν µ & ν µ : CDHSW (N), MINOS (N), Atmospheric (N), MiniBooNE/SciBooNE (N) No Osc. excluded at 6.3σ χ /NDF = 47.7/3 [Giunti, Laveder, Y.F. Li, H.W. Long, PRD 88 (013) ] [different approach and conclusions: Kopp, Machado, Maltoni, Schwetz, JHEP 1305 (013) 050] C. Giunti Phenomenology of Light Sterile Neutrinos Corfu 014 6September014 4 From Giunti et al Note: Kopp et al. 014 find worse GOF. In general, tension between appearance and disappearance oscillations. Also: some tension between oscillation and cosmology (not included above) 3

33 Need a redundant oscillation search, exploring a wide mass-mixing range, and cross-checking both appearance and disappearance, in order to discover (or rule out) conclusively light sterile neutrino states. ev per mill mixing sub-ev 33

34 Nonstandard interactions/processes in neutrino physics: no sightings so far, but they should always be kept in mind; examples in 0νββ decay: u e e u u e e u u e e u W W ν Standard u e e u W W N Heavy ν e u u e W ν(n) W Kaluza-Klein (KK±1 Brane:a=10 ±1 /GeV) p e e p W R,L W R,L ν L,R RHC λ,η λ=rh had, η=lh had u ~ u ~ g ~ SUSY g ~ π SUSY SUSY π π 34

35 Towards a larger picture and higher scales 1514 Leonardo 1543 Copernicus 35

36 Linking two fundamental research expeditions: 1. Test Higgs sector. Find ν masses 36

37 1 + Where are the ν s on this plot? Why are they so light? coupling to Higgs à ν? < 1 ev par@cle mass à 37

38 Options: coupling to Higgs à ν Dirac: neutrinos talk very weakly to the Higgs boson, y < 10-1 for unknown reasons... < 1 ev par@cle mass à 38

39 Options: coupling to Higgs à ν Majorana: neutrinos talk normally to the Higgs, but also to other (much) higher scale(s) M - - > suppression ym H /M < 1 ev par@cle mass à 39

40 Neutrinos masses may offer a great opportunity to jump beyond the EW framework via see-saw... M H M m(ν)... and to address fundamental physics issues, such as: new sources of CP violation at low and high energies lepton number violation and associated phenomena matter-antimatter asymmetry of the universe... 40

41 CP-violating decays of heavy neutrinos at scale M may generate lepton asymmetry (leptogenesis): Discovery of leptonic CP violation and of Majorana nature (+ proton decay?) would be important steps towards this scenario. M ~ GUT scale 41

42 CP-violating decays of heavy neutrinos at scale M may generate lepton asymmetry (leptogenesis). Discovery of leptonic CP violation and of Majorana nature (+ proton decay?) would be important steps towards this scenario. M ~ low scale At the other end of the spectrum, low-scale (e.g. EW) see-saw may also generate (at the price of fine-tuning) additional interesting phenomenology: dark matter candidates, di-lepton and heavy lepton events in HEP 4

43 CP-violating decays of heavy neutrinos at scale M may generate lepton asymmetry (leptogenesis). Discovery of leptonic CP violation and of Majorana nature (+ proton decay?) would be important steps towards this scenario. At the other end of the spectrum, low-scale (e.g. EW) see-saw may also generate (at the price of fine-tuning) additional interesting phenomenology: dark matter candidates, di-lepton and heavy lepton events in HEP In principle, several sterile states might even be split among widely difference energy scales, and contribute to various phenomena in (astro)particle physics. Let us remain open-minded! 43

44 EPILOGUE 44

45 EPILOGUE Terra Cognita... δm ~ 8x10-5 ev Δm ~ x10-3 ev sinθ1 ~ 0.3 sinθ3 ~ 0.5 sinθ13 ~

46 EPILOGUE Terra Cognita... δm ~ 8x10-5 ev Δm ~ x10-3 ev sinθ1 ~ 0.3 sinθ3 ~ 0.5 sinθ13 ~ 0.0 Terra Incognita... δ (CP) sign(δm) octant(θ3) absolute masses Dirac/Majorana 46

47 EPILOGUE Terra Cognita... δm ~ 8x10-5 ev Δm ~ x10-3 ev sinθ1 ~ 0.3 sinθ3 ~ 0.5 sinθ13 ~ 0.0 Terra Incognita... δ (CP) sign(δm) octant(θ3) absolute masses Dirac/Majorana...and beyond... new light states new heavy states nonstandard inter. flavor structure baryon asymmetry 47

48 EPILOGUE Further theoretical and experimental explorations will require significant time, resources and... good fortune! So, for neutrino physics, let us wish... 48

49 EPILOGUE Further theoretical and experimental explorations will require significant time, resources and... good fortune! So, for neutrino physics, let us wish... 49

50 Additional slides 50

51 (θ 13, δ) covariance plot.0 LBL Acc + Solar + KL + SBL Reactors + SK Atm.0.0 / / sin 13 sin sin sin 13 sin sin Current CP hint apparently stable for increasingly rich data sets. In combination, δ/π 1.4 and sinδ < 0 favored in both hierarchies Normal Hierarchy Inverted Hierarchy

52 0.06 LBL Acc + Solar + KL + SBL Reactors + SK Atm sin 13 sin sin 3 sin sin sin 3 sin sin Normal Hierarchy Inverted Hierarchy 5

53 ev 3 10 m ev 3 10 m sin 3 sin sin LBL Acc + Solar + KL + SBL Reactors + SK Atm sin 3 sin sin Normal Hierarchy Inverted Hierarchy 53

Updated three-neutrino oscillation parameters from global fits

Updated three-neutrino oscillation parameters from fits (Based on arxiv:14.74) Mariam Tórtola IFIC, Universitat de València/CSIC 37th International Conference on High Energy Physics 3th July 214, Valencia.