Solar and atmospheric ν s

Transcription

1 Solar and atmospheric ν s Masato SHIOZAWA Kamioka Observatory, Institute for Cosmic Ray Research, U of Tokyo, and Kamioka Satellite, Kavli Institute for the Physics and Mathematics of the Universe (WPI), U of Tokyo ICFA214 Seminar at Beijing October 27, 214 1

2 Solar and atmospheric ν s Masato SHIOZAWA Kamioka Observatory, Institute for Cosmic Ray Research, U of Tokyo, and Kamioka Satellite, Kavli Institute for the Physics and Mathematics of the Universe (WPI), U of Tokyo ICFA214 Seminar at Beijing October 27, 214 2

3 3-flavor oscillation scheme Flavor eigenstate Mass eigenstate t MNS (! e,! µ,! " ) =U t!i (! 1,! 2,! 3 ) U MNS : Maki-Nakagawa-Sakata Matrix! # # # "! e! µ! " $! & # & = # & # % " cos# 12 sin# 12 'sin# 12 cos# 12 1 $! &# &# &# %" cos# 13 sin# 13 e 'i$ 1 'sin# 13 e i$ cos# 13 $! &# &# &# %" 1 cos# 23 sin# 23 'sin# 23 cos# 23 $! &# &# & # %"! 1! 2! 3 $ & & & % Parameterized by 4 (mixing matrix) and 2 (difference of squared masses) θ23~45±5 o Δm 2 32 = ev 2 Atmospheric ν, Accelerator ν θ12~34±3 o Δm 2 21= ev 2 Solar ν, Reactor ν θ13~9 o Accelerator ν, Reactor ν, Atm & Solar ν δ=unknown Accelerator ν, Atmospheric ν Mass hierarchy (Δm 2 32=m 2 3-m 2 2> or Δm 2 32<) is also unknown: Accelerator ν, Atmospheric ν, reactor ν Solar&Atmospheric ν s played pioneering roles in the past ν oscillation studies and would also play important roles in future. 3

4 Atmospheric ν s Cosmic rays (proton etc) Proton, He Earth s atmosphere π" π" π! π" µ" e! νµ" νe! νµ" Super-Kamiokande! Wide range of ν energy (.1 GeV ~ 1 4 GeV and beyond) Wide range of ν baseline (1km downward ~ 13,km upward) νμ:νe ~ 2:1 at production ν oscillation study by high statistical data (>4, events in Super-K) and all three flavors (νe, νμ, ντ) Unique tests of ν s exotic property (4th ν, Lorentz violation, etc) 11

5 Early history of atmν s oscillations Prediction νμ ντ SK DATA Electron μ Dominant effect is νμ disappearance (discovered in 1998) Oscillatory signature (evidence in 24) 5

6 Dominant effect: νμ disappearance preliminary preliminary Super&K(Atm.(ν T2K(νµ(Run1&4 MINOS(Beam+(Atm(3f normal hierarchy inverted hierarchy Though consistent with accelerator ν experiments atmν allows more parameter space. sin 2 θ23 =.5 (maximal mixing) or <.5 or >.5 is still a open question (θ23 octant problem). 6

7 PRL 17, (211) 1 ( P(ν µ ν τ ) =1 sin 2 2ϑ sin Δm2 L+ * - ) E, ( P(ν µ ντ ) =1 sin 2 2ϑ sin Δm2 L + * ) E -, ν ν 2 Sub-GeV e-like 1-dcy e 5 SK-I+II+III 286 days Sub-GeV e-like -dcy e 2 νμ oscillation study ν and ν-bar differ cross sections flux event topology Sub-GeV µ-like -dcy e 5 Sub-Gev µ-like 1-dcy e -1 1 ) 2 (ev 2 m MINOS 2 sin SK ν " 68,9,99%CL SK ν " 9%CL 1 Sub-GeV -like 1-R 2 Multi-GeV e-like 2 Multi-GeV µ-like 2 Up Stop µ.6 SK 68,9,99%CL Sub-GeV µ-like 2-dcy e 2 1 Multi-Ring e-like 2 1 Multi-Ring µ-like 5 Non-showering µ ) 2 (ev 2 - m m 23 4 Sub-GeV -like M-R 5 PC Stop 2 PC Through 1 Showering µ lepton momentum [MeV] cos zenith cos zenith cos zenith sin Good constraints on anti-neutrino parameters. Data is consistent with CPT conservation sin

8 Evidence for τ neutrino appearance PRL 11, (213) Zenith Distribution of τ-like events SK-I+II+III 286 days Neural network to enhance events consistent with hadronic decays of τ Nτ DATA /Nτ exp =1.42±.35(stat) (syst) 3.8σ significance for null τ 3 τ OPERA (PRD89, 5112(R) (214)) Fi#ed&Excess Atm ν BKG&MC νμ ντ channel has been established. Atmospheric ν anomaly (problem) is finally concluded. 8

9 Atmospheric νe oscillation Through the matter effect in the Earth, we study on Mass hierarchy : resonance in multi-gev νe or νe CP δ : interference btw two Δm 2 driven oscill. θ23 octant : magnitude of the resonance Ψ(ν e )/Ψ (ν e ) 1 Ψ(ν e )/Ψ (ν e ) 1 Fractional change of upward νe flux (cosθzenith=-.8) ν cosθ ν =-.8 NH, sin 2 θ 23 =.4, sin 2 θ 13 =.25, δ=4 o cosθ ν =-.8 NH, sin 2 θ 23 =.6, sin 2 θ 13 =.25, δ=4 o (a) solar term interference term θ13 resonance term total (c) Eν(GeV) CP=4 o or 22 o (b) sin 2 θ23=.4 or cosθ ν =-.8 NH, sin 2 θ 23 =.6, sin 2 θ 13 =.25, δ=22 o cosθ ν =-.8 IH, sin 2 θ 23 =.6, sin 2 θ 13 =.25, δ=4 o (d) Eν(GeV) Hierarchy is NH or IH Resonance in νe (not shown) in the case of IH. 9

10 MH and δcp study preliminary Inverted Hierarchy PDG(reactors) preliminary SK#Atm SK+T2K#ν µ,ν e #Constraint T2K#ν µ,ν e #Constraint Normal Preference of normal hierarchy: χ 2 IH-χ 2 NH=.9 (SK only) 1.2 (T2K combined). Preference of δcp near 3π/2 is also strengthened by T2K CP conservation (sinδcp=) is still allowed at 9% CL Need more data 1

11 Sterile neutrino oscillations 4th ν(sterile ν) is indicated by LSND, MiniBooNE, reactor, solar ν exp s Effect of Uμ4 2 =.16 independent on the number of sterile νs and Δm 2 sterile constraints for 3+1 framework can be extended to 3+N constant constraints as long as Δm 2 sterile>.1ev 2 Uμ4 uniform μ deficit in angle/ energy Uτ4 shape distortion in angular distributions of high energy μ 11

12 Limits on sterile ν contribution arxiv:141.28, submitted to PRD preliminary preliminary CCFR PRL. 52, 1384 (1984) SK MiniBooNE + SciBooNE PRD86, 529 (212) Uτ4 2 9% CL Uμ4 2 9% CL Atmospheric ν data is consistent with 3-active ν framework (no sterileν contribution), and provides limits on mixings. 12

13 Lorentz invariance violating oscillations arxiv: , submitted to PRD No LV a T μτ=1-22 GeV c TT μτ=1-22 Consistent with null LIV New limits Provided 3~7 orders of magnitude better constraints than past 13

14 Future prospect of atmν studies: mass hierarchy determination Super-K 1996-present 5, ton 25 Hyper-K 225-1,, ton Δχ 2 Mass hierarchy sensitivity Normal hierarchy sin 2 2θ13=.1 Proton decay searches extends to discovery region Studies toward understanding full picture of neutrino oscillations CPV MH determination for any δ θ23 octant determination Astrophysical neutrino observatory Supernova ν Solar neutrino (~2ν ev/day) Hyper-K 1 years sin 2 θ23 band: due to δ 3 2 Whole allowed parameter space is covered by atmν only study 14

15 More for hierarchy study IceCube+DeepCore+PINGU ~22- E threshold down to O(1) GeV INO ~22-5kton Iron Calorimeter More than 3 σ sensitivities in both programs 15

16 Solar neutrino studies Pure νe source from pp-chain reactions and CNO cycle High statistical data available (>7, events in Super-K) Study on neutrino properties Search for new physics beyond the standard model Unique probe of solar structure & solar system formation 16

17 Latest oscillation results (global fit) Combined solar fit w/ KamLAND Without reactor θ13 constraint ~2σ tension in Δm 2 21 between solar and KamLAND Non-zero θ13 at ~2σ by solar and KamLAND only Good agreement with sin 2 θ13=.221±.12 by Daya Bay, RENO, and DC 17

18 Day/night asymmetry PRL112,9185(214) -- direct test of MSW effect -- First indication (at 2.8~3. σ) of terrestrial matter effects could be important achievement for future LBL and atmospheric ν studies in which the matter effect is relevant 18

19 Survival probability (spectrum) Pee~ 1-1/2sin 2 2θ12 Transition region - Test of MSW effect - non-standard physics Vacuum oscillation Pee~sin 2 2θ12 Matter-dominated resonant conversion 19

20 Probing the Unknown Gabriel D. Orebi Non-standard physics effects can alter the shape / position of the MSW rise Non-standard interactions (flavour changing NC) Sterile Neutrinos Mass varying neutrinos (MaVaNs) Friedland, Lunardini, Peña-Garay, PLB 594, (24) Holanda & Smirnov PRD 83 (211) Fig. 32. ν e survival probability in the Sun versus neutrino energy for the best fi point in the high- m 2 region in the presence of ED effects. The dotted line the survival probability M.C. forgonzalez-garcia, conventional oscillations (α i =)withthesamevalue M. of m 2 21, and θ 12. Thesesurvivalprobabilitieshavebeenobtainedforneutrino produced around x =.5 as it Maltoni is characteristic of 8 Band 7 Be neutrinos. Th data points are the extracted average survival probabilities for the low energy (pp intermediate energy Phys ( 7 Be, Rept pep and CNO) 46:1-129 and high energy(28) solar neutrinos ( 8 Ban hep) fromref.[235]. 2 neutrinos. This is illustrated in Fig. 33 where we show the result of such globa

21 Lower threshold in Super-K High-speed front-end electronics record every hits + Realtime reconst.+reduction software trigger Trigger efficiency is 1%@2.5MeV from 214 More data at the transition region is coming soon. 21

22 SNO+ measurement errors Also to cover ββ decay search, geo-ν, SNν, proton decays... 22

23 More on future prospect Borexino (phase-ii) continues the hunt for CNO cycle ν aiming to solve metallicity problem of the Sun. Clean (liquid Neon), XMASS (liquid Xenon) to measure pp-neutrino with 1%-level precision LENA for CNO and low energy 8 B JUNO, RENO precision measurements of parameters 23

24 Summary of atm & solar ν studies Oscillation studies toward full understanding of ν properties Solar θ12, Δm 2 21 measurements consistent with reactor results Indication of terrestrial matter effect Atmospheric ν provides complemental measurements of θ23, Δm 2 32 νμ disappearance consistent with νμ (CPT conservation) Need more data for mass hierarchy determination, θ23 octant, and δcp νμ ντ channel as a solution of atmospheric ν anomaly No indication of exotic effects such as neutrino decays, sterile ν, Lorentz invariance violation, etc. More solar neutrino experiments and data for oscillation studies, tests of exotic scenarios, and astrophysical studies 24