OVERVIEW OF NEUTRINO PHYSICS. A.K.Ichikiawa, Kyoto University

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1 OVERVIEW OF NEUTRINO PHYSICS A.K.Ichikiawa, Kyoto University 1

Preamble or excuse http://www.takaratomyarts.co.

of double β-decay detector. theorist experimentalist This 40 opening talk by theorist in last two conferences.

2 Preamble or excuse oana/kangaenai/ I have been working on accelerator-based long baseline neutrino oscillation experiments and recently on R&D of double β-decay detector. theorist experimentalist This 40 opening talk by theorist in last two conferences. Next talk, accelerator-based neutrino. The latest results will come from each projects in this workshop What should I talk??? Why & Why? As a result, I will talk about subjects which I am unfamiliar in front of experts! Many mistakes, biases and Questions! Be patient! 2

3 Neutrino Oscillation and neutrinoless double beta decay = Physics of MASS 3

4 What we know mass of fermions- 4

5 As an experimentalist, I made a mass distribution plot. log distribution of elementary fermion mass Planck GUT? Higgs s, μ, c, τ, b u, d ν,ν (assuming m 0) t e 5

A log-normal process is the statistical realization of the multiplicative product of many independent random

6 log-normal distribution Wikipedia, a continuous probability distribution of a random variable whose logarithm is normally distributed. A log-normal process is the statistical realization of the multiplicative product of many independent random variables, each of which is positive. example: annual incomes, reserve of oil fields People has n opportunities to multiply one s income. n follows normal distribution, but each time your income multiplicatively increase. 6

7 For example, I can imagin Universe expanded exponentially. If particle mass (Yukawa coupling) is inversely proportional to the space size, time fluctuation of mass determination results in lognormal distribution. 7

8 Planck 8 GUT? What is the origin of mass? mass by standard Higgs. log m =8.2 mass by? log m ~2 Higgs s, μ, c, τ, b u, d ν,ν (assuming m 0) t e

9 Minkowski,( 77), Yanagita( 79), GellMannn, Ramondo, Slansky( 79),Glashow( 79) Seesaw? If neutrino is Majorana-type, mass by? log m ~2 mass by standard Higgs. log m =8.2 0 mass term = N,N m m M N N diagonalize m M ν,ν (assuming m 0) u, d s, μ, c, τ, b Higgs M Planck GUT? Planck t e log M log GeV 9

10 Neutrino mass is suppressed by very high energy physics? mass by? log m ~2 mass by standard Higgs. log m =8.2 Planck GUT? N? Higgs s, μ, c, τ, b u, d ν,ν (assuming m 0) t e log M log GeV 10

11 Mixing between mass eigenstates up-type vs. down-type in quark charged vs. neutral in lepton quark U lepton U quark lepton θ θ θ S. Stone, ICHEP ( c 0 c13 0 s13e s i c 23 s13e 0 c cos, s sin ) i UPMNS c23 s12 c12 s 23 ij ij ij ij 13 c 0 s

55 0.14 0.47 0.53 0.71 0.31 0.65 0.69 Q.

weight particles as partner? θ 14 34 Or did partners pick up similar θ 2.3 46 weight?

12 Mixing between mass eigenstates up-type vs. down-type in quark charged vs. neutral in lepton quark U lepton U Q. about Yukawa coupling (~diagonal matrix) Did Fermions pick up similar quark lepton weight particles as partner? θ Or did partners pick up similar θ weight? θ S. Stone, ICHEP ( c 0 c13 0 s13e s i c 23 s13e 0 c cos, s sin ) i UPMNS c23 s12 c12 s 23 ij ij ij ij 13 c 0 s

13 Prospect of mixing angle determination High precision and redundant measurements 13

14 Prospect of mixing angle determination High precision and redundant measurements * may not be precise comparison PDG18 Let s hear talks for the latest values. ~2020 ~2027? ~2025? ~2030? assuming maximal mixing future Ploted sin θ to see the size of mixing 14

15 Mass Ordering normal m m m or inverted m m m? Big impact for neutrinoless double-beta decay search normal ordering lighter m Detector necessary ~1 ton vs 100 ton two ways proposed A) Matter effect in Earth for (anti-)ν antiν B) Amplitude difference for two frequencies 15

Mass Ordering A) Matter effect in Earth for

NO and IO 0 m 2E 2 2G n E 0 0 2E 0 0 0 0 0 0 U

different for ν and ν Effect of Earth matter

16 Mass Ordering A) Matter effect in Earth for (anti-) HU m 2E 0 0 sign different for NO and IO 0 m 2E 2 2G n E 0 0 2E U Especially, resonance happens at E sign different for ν and ν Effect of Earth matter has not yet observed due to relatively small sin 2θ 16

17 Mass Ordering B) Amplitude difference for two frequencies P ν ν leading term sin 2θ cos θ sin 0.69 m m Δm m L sin 4E for NO m for IO θ sin 0.31 Δm L 4E JUNO 17

18 Prospect of Mass Ordering determination * may not be precise comparison if δ= π/2 and NO (if not, NOvA+T2K) ~2024? ~2025? ~2027? ~2030? ~2030? This is sensitivity. Let s hear talk for actual result. 18

19 Prospect of determination High precision and redundant measurements * may not be precise comparison (NO case) PDG18 Let s hear talks for the latest values. ~2025? ~2027? similar for NOvA? future 0.4% ~2027? ~2030? <1% 19

20 Dirac CP phase ( c 0 c13 0 s13e s i c 23 s13e 0 c cos, s sin ) i UPMNS c23 s12 c12 s 23 ij ij ij ij 13 c s Quark case δ ~60 ~70 looks large, but cannot explain matter-dominant universe. Lepton case δ ~ 90??? Accelerator long baseline δ is dependent on definition. Jarlskog Invariant : independent of definition. show the size of CP violation effect. J Im U U U U sin 2θ sin 2θ sin 2θ cos θ sin δ Leptonic CPV can be much larger than Quark s 20

21 may or may not be related to matter-dominant universe, but may cause CPV which is sufficiently large to produce matter-dominant universe Leptogenesis CPV in N l H etc. Lepton asymmetry sphaleron Baryon asymmetry PDG2015 NEUTRINOMASS,MIXING, AND OSCILLATIONS sin θ sin δ 0.09 sin δ

22 Majorana CP phase If neutrino is Majorana type, U c s 0 s c e e c 0 s e s e 0 c c s 0 s c c cosθ,s sinθ Another two CP phases which cannot be accessible by oscillation 22

23 Neutrinoless double-beta decay Z n n ν ν e e Z 2 p p hatched width by Majorana-phases slide line Majorana-phases+oscillation par. uncertainty 90% uncertainty. m ev Inverted MO Normal MO T / G M m m U m m c m s e c m s e If measured, absolute mass and possibly Majorana phase m ev mtotev m ev

24 A. Giuliani The Mid and Long Term Future of Neutrinoless Double Beta Decay, Neutrino

25 Neutrinoless double- decay EXO-200 GERDA KamLAND-Zen Majorana CUORE 25

26 Neutrinoless double- KamLAND 2016 result decay Recent release 130 Te 136 Xe 76 Ge RL 117, (2016) 26

27 Neutrinoless double- KamLAND 2016 result decay Recent release 130 Te 76 Ge 136 Xe TPC Liquid Scinti. Bolometer Semiconductor future(a few year scale) sensitivity RL 117, (2016) 27

28 Neutrinoless double- KamLAND 2016 result decay Recent release 130 Te 136 Xe 76 Ge TPC Liquid Scinti. Bolometer Semiconductor future(a few year scale) sensitivity RL 117, (2016) 28

29 Direct mass measurement by -decay end point Probability ) (arb. u.) Figs from D. Parno, Neutrino 2018 m,eff = 1 ev m,eff = 0 ev kinetic kinetic energy energy - Q (ev) (ev) KATRIN Sensitivity : 0.24 ev in 5 years Other brand-new projects following, but lower sensitivity yet 29

30 Constraint from Cosmology Relic ν background relativistic=radiation at early time (during CMB acoustic oscillation) non-relativistic=dark matter at late time (during structure formation) N and m change both CMB and matter power spectra in peculiar manner - N : effective number of neutrino species = relativistic energy density excluding that by photons, in units of one neutrino. Sterile ν, if mix with active ν should be counted. - m : total light ν mass, m m m m Current bound N standard three ν) (note for 30

31 Constraint from Cosmology J. Lesgourgues Neutrino Properties from Cosmology, neutrino

32 Neutrino and the new physics or nuclear physics? 32

In ~10 years, Oscillation Δm,Δm, MO CMB m m m Double-β m β m If inconsistent, Non-standard interaction L 2 lepton # violation sterile-ν cosmological problem.

33 In ~10 years, Oscillation Δm,Δm, MO CMB m m m Double-β m β m If inconsistent, Non-standard interaction L 2 lepton # violation sterile-ν cosmological problem. m ev 10 double β-decay CMB Inverted MO Normal MO DBD life time is affected by L 2 new physics. 10 F.Deppisch, neutrino m ev mtotev m ev 33

34 neutrinoless double- decay T / G M m M : nuclear matrix element cannot be directly measured only partial strength factor 2~3 different for different calculation axial current coupling constant g might be significantly smaller in nuclei T / g 34

experiments σ G N 4π E First detection by COHERENT.

35 Coherent Elastic Neutrino-Nucleus Scattering (CE NS) Summation at amplitude level sensitivity by CEνNS experiments σ G N 4π E First detection by COHERENT. and many projects following. Let s hear! CsI[Na] MS renormalization 35

36 H. Wong Neutrino-nucleus Coherent Scattering with Reactor and Solar Neutrinos, neutrino

Reactor `anomaly RENO : y f = (5.785 + 0.113) x 10 43 cm 2 /fission H M model : y f = (6.271 + 0.

37 Reactor `anomaly RENO : y f = ( ) x cm 2 /fission H M model : y f = ( ) x cm 2 /fission Reno, Daya Bay, Double Chooz See talks I. Yu, Recent Results from RENO neutrino

38 Reactor another issue Excess at ~5 MeV all for RENO/Daya Bay/Double Chooz Right plot by RENO with 458-days data Let s hear updates Phys.Rev.Lett. 116 (2016) no.21,

Reactor `anomaly could be ~1eV sterile, but Reactor flux predicted by using measured fission βspectra and/or nuclear databases for > 1000 daughters and > 6000 β-branches ν spectrum of each β-decay :

39 Reactor `anomaly could be ~1eV sterile, but Reactor flux predicted by using measured fission βspectra and/or nuclear databases for > 1000 daughters and > 6000 β-branches ν spectrum of each β-decay : S(E e, Z, A) G 2 F 2 p ee 3 e (E 0 E e ) 2 C(E)F(E e, Z, A)(1 corr (E e, Z, A)) Recent measurements with fuel evolution giving hints. correlation with fuel composition change Maybe, in coming talks Daya Bay, Chinese Physics C, 2017, 41 39

40 Very short baseline experiments Tring to catch oscillation feature (L/E dependence) T. Lasserre SOLID (Belgium) STEREO (France) NEOS(Korea) DANSS (Russia) 40 Prosepect(US)

41 !?? Plots from neutrino2018 talks NEOS 10 m 2 [ev 2 ] 1 DANSS SBL Diss. RAA GA CLs Excluded: 99% CL 95% CL 90% CL 0.1 Dn / Up STEREO DANSS PROSPECT 41

42 Atmospheric and accelerator experiments Flux prediction affected by hadron production uncertainty neutrino-nucleus interaction... Let s hear talks! 42

43 LSND & MiniBooNE anormaly LSND, 1995 New (positive) results from MiniBooNE! Conflicting with ICECUBE, MINOS+, Daya Bay if mixing with 4 th ν Acc. short baseline experiments in FNAL and J-PARC will investigate. IsoDAR, too. Let s hear talks. 43

44 Neutrino as a window to Universe 44

45 astrophysical neutrino spectrum J. Becker, Phys. Rept. 458 (2008)173 45

46 Solar neutrino Predicted flux A. Serenelli, Eur.Phys.J. A52 (2016) no.4, 78 And the density is as high as ρ ~150g/cm at the center. Significant matter effect 46

47 Borexino Data taking phase I 2007~2010 phase II 2011~2017 Ethreshold=250keV O. Smirnov, Solar neutrino from pp-chain and other results of Borexino, neutrino 2018 >5σ for pep signal 47

Supernovae neutrino waiting since 1987 K.

48 Supernovae neutrino waiting since 1987 Rencontres du Vietnam,

Supernova Burst neutrino expectation by Hyper-K, DUNE and IceCube I.Tamborra et al. Phys. Rev. D 90, 045032 (2014) Sensitive to ~4Mpc.

49 Supernova Burst neutrino expectation by Hyper-K, DUNE and IceCube I.Tamborra et al. Phys. Rev. D 90, (2014) Sensitive to ~4Mpc. Then, 0.3~1 events/yrs Hyper- K Even νν interaction plays role Explosion mechanism, NS/BH formation multi-messenger observation DUNE 49

50 Supernova Relic Neutrino J. F. Beacom, M. R. Vagins, Phys.Rev.Lett. 93 (2004)

51 SK-Gd project aiming to detect Supernova Relic Neutrino dissolve Gd to SK water detect ν p e n neutron tagged by Gd neutron capture (~8 MeV γ s released.) Late 2019 or later 51

52 Origin of heavy elements and neutrino r(rapid)-process is necessary to produce gold etc. Requires 10 ~10 neutrons/cm 3 a few hours to days~1s ~1 second 52

$fraction of neutrons decreases r-process unlikely to happen https://astro.physik.unibas.ch/fileadmin/user_upload/astro physik-unibas-ch/liebendoerfer/supernova_models.$

53 Origin of heavy elements and neutrino Supernova explosion Gravitational collapse of massive star Proto Neutron star Explosion by neutrinos Two reactions happen ν n pe ν p ne fraction of neutrons decreases r-process unlikely to happen physik-unibas-ch/liebendoerfer/supernova_models.html 53

54 Origin of heavy elements and neutrino Binary neutron-star merger Gravitational wave observation GW ele. mag. observation of kilonova : thermal glow by radioactive decay of isotopes of the heavy elements Binary neutron-star merger can be a dominant mode of r-process production high neutron fraction only heavy elements neutrino irradiation lower neutron fraction light elements Observation of those neutrinos would be very interesting, but the event rate may be too low. Astrophys.J. 848 (2017) no.2, L12 54

55 Ultra high energy cosmic ray Accelerated by? CMB etc. pp/γ Nπ π ν,ν 50~100 PeV proton is necessary to produce 25 TeV~5 PeV neutrino γ A. Connolly, Reaching for the highest energy neutrinos, neutrino

56 Astrophysical -rays and neutrinos Let s hear updates from IceCube Especially, multimessager observation : IceCube A & Blazer TXS No evidence for point sources at this point F.Halzen High-energy neutrino astrophysics, Nature Phys. 13 (2016) no.3,

57 Cosmic neutrino background (C B) J. Becker, Phys. Rept. 458 (2008)173 Can see Universe 1s after Big Bang. c.f. 380,000 years for CMB λ~7 mm if m 0 λ~0.6 mm if m 10meV 57

58 P.F.Smith Prospects for Relic Neutrino Detection RAL C B interaction Huge cross section thanks to volume coherence. If σ 10 cm and Φ 10 /cm s, ν e interaction rate is 3/g s! But almost no recoil with ~1mm 3 target 58

59 How to detect C B? End point of electrons from Tritium β-decay Proposed by S. Weinberg in 1962 a few projects trying direct ν mass measurements CνB by accelerator??? Accelerate He and detect tritium and positron He ν te Necessary He energy = 520 TeV for m 100meV. (cf. 10 MeV for reactor ν ) Superconducting detectors? 59

60 How to detect C B? End point of electrons from Tritium β-decay Inspired this topic, one idea. Proposed by S. Weinberg in 1962 ν appearance experiment: a few projects reactor trying direct ν mass measurements (ν ν accelerator p μ n CνB by accelerator??? E 19 GeV Accelerate At J-PARC He and proton detect tritium beam and energy, positroncross section is He ν te comparable to that at E ~1 GeV There is a reactor. Necessary I will calculate He energy = event 520 TeV rate for during m 100meV. this (cf. 10 workshop. MeV for reactor ν ) Superconducting detectors? 60

61 Conclusion To prepare this talk, I read through PDG reviews and neutrino2018 slides. Impressed by variety and high activity in this field!!! 61

62 appearance experiment: reactor peak energy 3~4 MeV baseline length 1.5 km Luminosity L2cN ρ N for J-PARC one turn case ~3E14 /s storage ring 100m x3 straight section ~3E20 /s ρ for Tokai-Daini-nuclear pant Thermal power 3 GW 6E20 ν/s L=1.3E30 /s cross section 2.1E9/c /cm3 s 1146 MeV for E 3.5 MeV E 231 MeV for fixed target σ1e-40 cm 2 Event rate (storage case) 1E-10 /s (times oscillation probability) Hmmmm 62

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