Low Energy Neutrinost in SuperKamiokande TAUP 2015 Torino

Low Energy Neutrinost in Super-Kamiokande TAUP 2015 @Torino September 7 2015 Hiroyuki Sekiya ICRR, University of Tokyo for the Super-K Collaboration Hiroyuki Sekiya TAUP 2015 Torino September 7 2015

Super-Kamiokande 50 kton pure water Cherenkov detector 1 km (2. 7 km w. e) underground in Kamioka 11129 50 cm PMTs in Inner Detector 1885 20 cm PMTs in Outer Detector Physics targets of Super-Kamiokande This talk ν r la So N S lic e R ~3. 5 Me. V ~20 Hiroyuki Sekiya ay c e ν ~100 d n o ot Pr WI Atmospheric ν Te. V ~1 Ge. V TAUP 2015 s P M Torino September 7 2015 2

Super-K n + e- Solar neutrinos observation Hiroyuki Sekiya TAUP 2015 ne Torino September 3 7 2015

SK 8 B Solar neutrino observation SK has observed solar neutrino ◦ ~77000 solar interactions for 18 years(~ 1. 5 solar cycle) SK I-IV combined flux 2. 341± 0. 044(stat. +syst. ) − 1 x 106 cm− 2�� �� �� Phase Energy threshold Me. V(kin. ) Live time (say) 8 B Flux × 106/cm 2/sec SK-I 4. 5 1496 2. 38± 0. 02± 0. 08 SK-II 6. 5 791 2. 41± 0. 05+0. 16 -0. 15 SK-III 4. 0 548 2. 40± 0. 04± 0. 05 SK-IV 3. 5 2034 2. 31± 0. 02± 0. 04 y ar n i lim e pr Hiroyuki Sekiya TAUP 2015 DATA/MC = 0. 4459± 0. 0084(stat. +syst. ) Torino September 7 2015 4

Time variation of 8 B solar neutrino flux No correlation with the 11 years solar activity is observed. Super-K solar rate measurements are fully consistent with a constant solar neutrino flux emitted by the Sun. c 2 = 13. 10/18(dof) Preliminary SK-II SK-IV SK-III Sun spot number was obtained by the web page of NASA http: //solarscience. msfc. nasa. gov/greenwch/spot_num. tx t Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 5

Oscillation analysis: Solar global fit This SK update and other latest results are combined. Without reactor θ 13 constraint Combined solar fit with Kam. LAND preliminary sin 2θ 13=0. 0242± 0. 0026 Solar Kam. LAND Solar+Kam. LAND Solar Reactor Non-zero q 13 at 2 s from solar+Kam. LAND Good agreement with Daya Bay, RENO & DC ~2σ tension in Δm 221 between solar and Kam. LAND Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 6

Search for the direct MSW signal Current main motivation of SK 8 B observation Energy spectrum distortion Flux day-night asymmetry “Nighttime regeneration” of e by earth matter effect Neutrino survival probability Vacuum oscillation dominant Solar+Kam. LAND sin 2θ 12=0. 308 Δm 221=7. 50 x 10 -5 e. V 2 up -t ur Solar sin 2θ 12=0. 311 Δm 221=4. 85 x 10 -5 e. V 2 n! Matter oscillation dominant JHEP 0311: 004(2003) Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 7

SK I-IV combined recoil spectrum Test of “spectrum upturn” ◦ MSW is slightly disfavored by ~1. 7 σ using the Solar + Kam. LAND best fit parameters ~1. 0 σ using the Solar Global best fit parameters. Total # of bins of SK I-IV is 83 χ2 Solar + Kam. LAND 70. 13 Solar global 68. 14 Quadratic fit 67. 67 Exponential 67. 54 Hiroyuki Sekiya Preliminary All SK phases are combined without regard to energy resolution or systematics in this figure. Statistic error only 8 BMC: 5. 25× 106/cm 2/sec Neutrino energy spectrum is convoluted in the electron recoil spectrum. For de-convolution, generic functions are used as a survival probability; TAUP 2015 Torino September 7 2015 8

Solar best fit sin 2θ 12=0. 311 Δm 221=4. 85 x 10 -5 e. V 2 Day-Night flux asymmetry preliminary Solar+Kam. LAND sin 2θ 12=0. 308 Δm 221=7. 50 x 10 -5 e. V 2 preliminary θz Earth Sun Δm 221=4. 84 x 10 -5 e. V 2 sin 2θ 12=0. 311 sin 2θ 13=0. 025 Fitted asymmetry amplitude Δm 221=4. 84 x 10 -5 e. V 2 Δm 221=7. 50 x 10 -5 e. V 2 SK-I -2. 0± 1. 8± 1. 0% -1. 9± 1. 7± 1. 0% SK-II -4. 4± 3. 8± 1. 0% -4. 4± 3. 6± 1. 0% SK-III -4. 2± 2. 7± 0. 7% -3. 8± 2. 6± 0. 7% SK-IV -3. 6± 1. 6± 0. 6% -3. 3± 1. 5± 0. 6% combined -3. 3± 1. 0± 0. 5% -3. 1± 1. 0± 0. 5% non-zero significance 3. 0σ 2. 8σ Hiroyuki Sekiya SK-I - IV combined TAUP 2015 (Eth=4. 5 Me. V for SK-I, III, IV 6. 5 Me. V for SK-II) This is the “direct” indication for matter enhanced neutrino oscillation Torino September 7 2015 9

DSNB (SRN) 1010 stellar/galaxy × 1010 galaxies × 0. 3%(become SNe) ~O(1017)SNe ar. Xiv: 1307. 5458, 1004. 3311 NOW Neutrinos from past SNe 8 B hep １ billion years ago DSNB e DSNB c atm m e 10 billion years ago Beginning of the universe Hiroyuki Sekiya Theoretical flux prediction : 0. 3~1. 5 /cm 2/s (17. 3 Me. V threshold) Super-K should be most sensitive to e TAUP 2015 Torino September 7 2015 10

Status of DSNB search Search window for SRN at SK : From ~10 Me. V to ~30 Me. V Limited by BG. More than 1 order reduction is needed. Comparison with Expected e spectra ◦ n tagging efficiency (by proton) is low… PRD 79 08013(2009) BG subtracted 11 Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 11

SK-Gd project Beacom and Vagins PRL 93, 171101 (2004) Identify ep events by Large cross section Captures on Gd neutron tagging with Gadolinium. for thermal neutron (48. 89 kb) Neutron captured Gd emits 3 -4 s in total 8 Me. V Gd 2(SO 4)3 was selected to dissolve. 100 % 0. 1% Gd (0. 2% in Gd 2(SO 4)3) gives ~90% efficiency for n capture 80 % 60 % 40 % In Super-K this requires dissolving ~100 tons of Gd 2(SO 4)3 20 % 0% 0. 0001 0. 001% % 0. 01 % 0. 1% 1% Gd in Water Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 12

Expected signal with SK-Gd 10 years SRN flux from Horiuchi et al. PRD, 79, 083013 (2009) Assumption n capture efficiency: 90% Gd detection efficiency: 74%. 35% of the SK-IV invisible muon BG ◦ By n-tagging Min/nominal/Max are due to uncertainties in astronomy. Expect number of events in 10 years in Etotal =10 -30 Me. V Teff 6 Me. V case: 26 -34 events Teff 4 Me. V case: 13 -16 events Background: ~18 events Aiming at “discovery” of SRN Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 13

EGADS 200 m 3 tank with 240 PMTs Evaluating Gadolinium’s Action on Detector Systems To study the Gd water quality with actual detector materials. The detector fully mimic Super-K detector. : SUS frame, PMT and PMT case, black sheets, etc. EGADS 2014 Gd water circulation system (purify water with keeping Gd) 15 m 3 tank to dissolve Gd Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 14

Water transparency during adding Gd had been dissolved from Nov. 2014 to May. 2015 Hiroyuki Sekiya TAUP 2015 Torino September 23 7 2015 15

Water transparency after Gd conc. got 0. 2% SK-III and SK-IV value Top Middle Bottom The light left at 15 m in the 200 m 3 tank was very stable and ~75% for 0. 2% Gd 2(SO 4)3 , which corresponds to ~92% of SK-IV pure water average Effect on the vertex resolution Hiroyuki Sekiya TAUP 2015 Effect on the energy resolution Torino 23 September 7 2015 16

Neutron capture signal in EGADS Using Delayed signal spectrum Am/Be + BGO Data MC Time to delayed signal Data MC Gd concentration dependence was confirmed. [μsec] Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 17

Official statement from SK collaboration Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 18

Summary Solar observation • • • SK has observed ~77000 8 B interactions over 18 years, by far the largest sample of solar neutrino events in the world. – No correlation with the solar activity cycle. SK recoil electron energy spectrum slightly disfavors “MSW upturn” SK data provide the first indication (at 2. 8~3. 0 s) of terrestrial matter effects on 8 B solar oscillation. For DSNB detection Gd project in SK (was known as GADZOOKS!) started in 2002. • EGADS started in 2009 to evaluate Gd effect to SK. • In 2015, 0. 2% of Gd sulfate was dissolved in EGADS and it was confirmed that there is no showstopper for putting Gd into SK. SK-Gd was accepted by Super-K in June 2015. • Stay tuned for low energy SK neutrino Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 19

Extra Slides Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 20

History of Gd project in Super-K 2002 Nov. Started to discuss as “GADZOOKS!” 2006 May. Gd Advisory Committee was formed. List up R&D items and specifications 2007 Nov. collaboration council It was suggested to make a test tank and study feasibility. 2009 “EGADS” was started. A 200 ton test tank was constructed. 2013 0. 2% Gd 2(SO 4)3 was dissolved before mounting PMTs and transparency was measured. EGADS 2013 summer 240 PMTs were mounted in the EGADS tank. 2014 Oct. – 2015 May Dissolved 0. 2% Gd 2(SO 4)3 again and checked water transparency. 2015 Jun. collaboration council GADZOOKS! was approved as “Super Kamiokande Gd” Hiroyuki Sekiya TAUP 2015 Torino EGADS hall 2009 EGAD S 2014 September 7 2015 21

Timeline of SK-Gd 201 X Numbers in parentheses are months to be taken for the work 201 X 20 XX T 0 = Start leak stop work(~3. 5) Pure water circulation ～～ Fill water(~2) T 1 = Load first Gd 2(SO 4)3 1 t=0. 002% (~1) T 2 = Load full Gd 2(SO 4)3 100 t=0. 2% (~2) Observation Stabilize water transparency ～～ Load Gd 2(SO 4)3 10 t (~1) Observation In order to set T 0, T 1, &T 2, T 2 K schedule will be also taken into account Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 22

Why Gd (not 2. 2 Me. V γ) for neutron tagging Number of hit PMT (Nhit) distributions Nhit > 15 Vertex reconstruction is possible. 2. 2 Me. V from p+n Gd(n, )G d cascade Efficiency and fake probability 2. 2 Me. V : Efficiency: 10～ 20%, fake probability: ～ 10 -2 Gd(n, )Gd: Efficiency: >80%, fake probability: <10 -4 Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 23

Improvement for Proton decay Neutron multiplicity for P e+ 0 MC Atmospheric BG Accompany many n 92. 5% Zero n If one proton decay event is observed at Super-K after 10 years Current background level: 0. 58 events/10 years Background with neutron anti-tag: 0. 098 events/10 years Background probability will be decreased from 44%(w/o n) to 9%(w/ n). Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 24

Improvement for T 2 K Number of tagged neutrons in T 2 K energy range NEUT 5. 1. 4. 2 Atmospheric neutrino 1 -ring e-like sample 0. 5 Ge. V < E < 0. 7 Ge. V Assuming n-tag efficiency of 80%. (capture eff. =90%, Gd- det. eff. =~90%) Using n-tagging information, ν e ID (νe miss. ID) eff. ~70%(30%) Hiroyuki Sekiya TAUP 2015 Torino 15 7 2015 September 25

ν e enhanced sample in anti mode appearance analysis Signal ν e, Signal νe ν e, νμ and ν μ ν e enhanced sample BG sample Erec[Ge. V] Number of events @ 3. 9× 1021 POT Osc parameters: sin 22θ 13=0. 1, δcp=-90°, Δm 232 = 0. 0024 e. V 2, sin 2θ 23=0. 5, NH ν e ID (νe miss. ID) eff. =70%(30%) is assumed w/o energy dependence Note: Directional information of e/e+ is not used Hiroyuki Sekiya TAUP 2015 Torino Erec[Ge 16 V] September 7 2015 26

Anti mode 3. 9× 1021 Appearance Contour W/ Gd W/o Gd 90%C. L Δχ2 True parameters: sin 22θ 13=0. 1, δcp=-90° Δm 232 = 0. 0024 e. V 2 (Fixed), sin 2θ 23=0. 5(Fixed), NH(Fixed) W/ Gd W/o Gd θ 13 Fixed Only stat error Hiroyuki Sekiya TAUP 2015 Only stat error Torino δCP September 7 2015 27

separation e MC (ex. 500 Me. V/c) MC fi. TQun L 0/Le e/ pure Gd water fi. TQun 0 mass (Me. V/c 2) 0 MC, remain true (%) pure Gd water e MC, det. true pure (%) (Me. V/c) Gd water 250 92. 9± 2. 1 91. 9± 2. 1 250 1. 7± 0. 2 1. 9± 0. 2 500 89. 3± 2. 0 88. 4± 2. 0 500 4. 7± 0. 3 6. 1± 0. 4 1000 75. 7± 1. 8 77. 7± 1. 8 1000 15. 8± 0. 7 16. 7± 0. 7 Hiroyuki Sekiya (Me. V/c) TAUP 2015 Torino 28 September 7 2015 28

Recent SK Solar neutrino results SK has observed solar neutrino for 17 years(~ 1. 5 solar cycle) ◦ Fully consistent with a constant solar neutrino flux emitted by the Sun 4500 days of data, ~70000 solar interactions ◦ SK data provide the first indication (at 3. 0 s) of terrestrial matter effects on 8 B solar oscillation. ry p Hiroyuki Sekiya a in lim e r TAUP 2015 Torino September 7 2015 29

Improvements in SK-IV Reduced 222 Rn New BG 4. 0 -4. 5 Me. V bin SK-III analysis in low energy bins Remaining BG-electrons from 214 Bi should have more multiple-scatterings than signal-electrons have: MSG SK-IV 3. 5 -4. 0 Me. V MSG < 0. 35<MSG<0. 45<MSG 4. 0 -4. 5 Me. V l Reduced systematic error 1. 7% for flux cf. SK-I: 3. 2% SK-III: 2. 1% Achieved 3. 5 Me. V(kin. ) energy threshold 8. 6 s signal is observed with MSG Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 30

Recoil electron spectra SK-IV 1669 days Preliminary MC: 5. 25× 106/cm 2/sec Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 31

N. B. All SK phase are combined without regard to energy resolution or systematics in this figure SK-I+II+IV spectrum Solar+Kam. LAND sin 2θ 12=0. 308 Δm 221=7. 50 x 10 -5 e. V 2 Solar sin 2θ 12=0. 311 Δm 221=4. 85 x 10 -5 e. V 2 (total # of bins of SKI - IV is 83) χ2 Solar+Kam. LAND 70. 13 Solar 68. 14 quadratic fit 67. 67 exponential fit 66. 54 Neutrino energy spectrum is convoluted in the electron recoil spectrum. For de-convolution, generic functions are used as a survival probability; f 8 B=5. 25 x 106/(cm 2∙sec) fhep=7. 88 x 103/(cm 2∙sec) SK recoil electron spectrum constrain the fit parameters (ci, ei) of the function and the allowed Pee(E ) is derived using the allowed (ci, ei). Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 32

Allowed Pee(En) for SK preliminary Solar+Kam. LAND sin 2θ 12=0. 308 Δm 221=7. 50 x 10 -5 e. V 2 SK Solar sin 2θ 12=0. 311 Δm 221=4. 85 x 10 -5 e. V 2 ✓MSW (solar+Kam. LAND) is consistent at ~1. 6σ ✓MSW (solar) fits better (at ~0. 7σ) Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 33

Allowed Pee(En) for SK+SNO preliminary Solar+Kam. LAND sin 2θ 12=0. 308 Δm 221=7. 50 x 10 -5 e. V 2 SNO SK SK+SNO Solar sin 2θ 12=0. 311 Δm 221=4. 85 x 10 -5 e. V 2 ✓SK and SNO are complementary for the shape constraint ✓MSW is consistent at 1σ Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 34

Global view of Pee(En) preliminary all solar (pp) Borexino (pep) Borexino (8 B) Borexino (7 Be) SK+SNO Homestake +SK+SNO (CNO) Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 35

Day/Night asymmetry amplitude preliminary Energy-dependence of the variation Rate/Rateaverage expected Δm 221=4. 84 x 10 -5 e. V 2 sin 2θ 12=0. 311 sin 2θ 13=0. 025 Fitted asymmetry amplitude Hiroyuki Sekiya Δm 221=4. 84 x 10 -5 e. V 2 Δm 221=7. 50 x 10 -5 e. V 2 SK-I -2. 0± 1. 8± 1. 0% -1. 9± 1. 7± 1. 0% SK-II -4. 4± 3. 8± 1. 0% -4. 4± 3. 6± 1. 0% SK-III -4. 2± 2. 7± 0. 7% -3. 8± 2. 6± 0. 7% SK-IV -3. 6± 1. 6± 0. 6% -3. 3± 1. 5± 0. 6% combined -3. 3± 1. 0± 0. 5% -3. 1± 1. 0± 0. 5% non-zero significance 3. 0σ 2. 8σ TAUP 2015 Torino First observation of day/night asymmetry at 3 s significance level September 7 2015 36

Δm 221 dependence sin 2θ 12=0. 311, sin 2θ 13=0. 025 preliminary 1σ Solar 3. 0σ 1σ Kam. LAND 2. 9σ 2. 8σ Solar region expected SK-I, III, IV best fit differ from zero by 2. 9~3. 0σ agree with expect by 1. 0σ Kam. LAND region differ from zero by more than 2. 8σ agree with expect by 1. 3σ Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 37

History of lowered BG and threshold Solar angle distributions ◦ BG SK-I/SK-IV=1/4, Eth SK-I – SK-IV = 1 Me. V 3. 5 Me. V-4. 0 Me. V bin 4. 5 Me. V-5. 0 Me. V bin SK-III SK-IV y r na p Hiroyuki Sekiya i m i l re TAUP 2015 y e pr Torino lim September 7 2015 ar in 38

How it was achieved? It’s easy! Just tightening the FV to reject Rn rich region. SK-IV vertex distributions 8. 8 kton 13. 3 ton r 2[m 2] Keeping Event rates Hiroyuki Sekiya 4. 5 - 5. 0 Me. V 4. 0 - 4. 5 Me. V 3. 5 - 4. 0 Me. V r 2[m 2] the FV (boarder) is not easy at all! SK IV SK III TAUP 2015 Torino SK IV SK III September 7 2015 39

Convection suppression in SK-IV Very precisely temperature-controlled (± 0. 01 o. C) water must be supplied to the bottom. Return to Water system 3. 5 Me. V-4. 5 Me. V Event distribution Temperature in Z derection The difference is only 0. 2 o. C Purified Water supply r 2 Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 40

Summary Hiroyuki Sekiya SK has observed ~70000 solar interactions, by far the largest sample of solar neutrino events in the world. SK data provide the first indication (at 2. 8~3. 0 s) of terrestrial matter effects on 8 B solar oscillation. SK gives the world’s strongest constraints on the shape of the survival probability Pee(Eν) in the transition region between vacuum oscillations and MSW resonance. ◦ SK spectrum results are consistent with MSW up-turn prediction within ~1 s. SK measurements strongly constrain neutrino oscillation parameters: ◦ SK gives world’s best constraint on Δm 212 using neutrinos. ◦ There is a 2 s tension between SK’s neutrino and Kam. LAND’s antineutrino measurement of Δm 212. Last month SK started taking data at ~2. 5 Me. V at ~100% trigger efficiency. Stay tuned for very low energy SK neutrino. TAUP 2015 Torino September 7 2015 41

Full summary SK has observed ~70000 solar neutrino interactions in ~4500 days (1. 5 solar cycles), by far the largest sample of solar neutrino events in the world. SK data provide the first indication (at 2. 8~3. 0 sigma) of terrestrial matter effects on 8 B solar neutrino oscillation. This is the first observation using a single detector and identical neutrino beams that matter affects neutrino oscillations. SK has successfully lowered the analysis threshold to ~3. 5 Me. V kinetic recoil electron energy. SK gives the world’s strongest constraints on the shape of the survival probability Pee(Eν) in the transition region between vacuum oscillations and MSW resonance. SK spectrum results slightly disfavor the MSW resonance curves, but are consistent with MSW prediction within 1 -1. 7 sigma. SK measurements strongly constrain neutrino oscillation parameters: SK uniquely selects the Large Mixing Angle MSW region by >3 sigma, gives world’s best constraint on solar Δm 2 using neutrinos, and significantly contributes to the measurement of the solar angle. There is a 2 sigma tension between SK’s neutrino and Kam. LAND’s anti-neutrino measurement of the solar Δm 2. Last month SK started taking data at ~2. 5 Me. V at ~100% trigger efficiency. Stay tuned for very low energy SK solar neutrino Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 42

Wide-band Intelligent Trigger Reconstruction and Reduction just after Front-end 100% trigger efficiency above 2. 5 Me. V(kin. ) Just started Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 43

Oscillation parameter Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 44

Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 45

SK+SNO 8 B total flux For each oscillation parameter set there is a minimum chi 2 and a 8 B error term describing the parabolic increase of the chi 2 with deviations from the best chi 2. The reduced chi 2 vs. 8 B flux is below. The jump is due to the relatively coarse grid in theta 12. 5. 30+0. 17 -0. 11 x 10^6/(cm 2 sec), which is a (+3%, -2%) error on the total 8 B for SK+SNO compared to the 1. 5% error of SK's ES flux by itself. Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 46

Systematic errors Total 1. 7 % Hiroyuki Sekiya Source SK-IV flux (3. 5 -19. 5 Me. V) SK-III flux (4. 5 -19. 5 Me. V) energy scale +1. 14, -1. 16% ± 1. 4% energy resolution +0. 14, -0. 08% ± 0. 2% B 8 spectrum +0. 33, -0. 37% ± 0. 2% trigger efficiency ± 0. 1% ± 0. 5% angular resolution +0. 32, -0. 25% ± 0. 67% vertex shift ± 0. 18% ± 0. 54% BG event cut ± 0. 36% ± 0. 4% hit pattern cut ± 0. 27% ± 0. 25% another vertex cut removed ± 0. 45% spallation cut ± 0. 2% gamma cut ± 0. 26% ± 0. 25% cluster hit cut +0. 45, -0. 44% ± 0. 5% BG shape ± 0. 1% signal extraction ± 0. 7% cross section ± 0. 5% TAUP 2015 Torino September 7 2015 47

Data set for global solar analysis The most up-to-date data are used SK: ◦ ◦ SK-I 1496 days, spectrum 4. 5 -19. 5 Me. V(kin. )+D/N: Ekin>4. 5 Me. V SK-II 791 days, spectrum 6. 5 -19. 5 Me. V(kin. )+D/N: Ekin>7. 0 Me. V SK-III 548 days, spectrum 4. 0 -19. 5 Me. V(kin. )+D/N: Ekin>4. 5 Me. V SK-IV 1669 days, spectrum 3. 5 -19. 5 Me. V(kin. )+D/N: Ekin>4. 5 Me. V SNO: ◦ Parameterized analysis (c 0, c 1, c 2, a 0, a 1) of all SNO phased. (PRC 88, 025501 (2013)) ◦ Same method is applied to both SK and SNO with a 0 and a 1 to LMA expectation Radiochemical: Cl, Ga ◦ Ga rate: 66. 1± 3. 1 SNU (All Ga global) (PRC 80, 015807 (2009)) ◦ Cl rate: 2. 56± 0. 23 SNU(Astrophys. J. 496, 505 (1998) ) Borexino: Latest 7 Be flux (PRL 107, 141302 (2011)) Does NOT include Borexino pp 2014 Kam. LAND reactor : Latest (3 -flavor) analysis (PRD 88, 3, 033001 (2013)) 8 B spectrum: Winter 2006 (PRC 73, 025503 (2006)) 8 B and hep flux f 8 B=5. 25 x 106/(cm 2∙sec) fhep=7. 88 x 103/(cm 2∙sec) Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 48

Day/Night (sin 2θ 12=0. 311, sin 2θ 13=0. 025) Amplitude fit Straight calc. Δm 221=4. 84 x 10 -5 e. V 2 Δm 221=7. 50 x 10 -5 e. V 2 (D-N)/((D+N)/2) SK-I -2. 0± 1. 8± 1. 0% -1. 9± 1. 7± 1. 0% -2. 1± 2. 0± 1. 3% SK-II -4. 4± 3. 8± 1. 0% -4. 4± 3. 6± 1. 0% -5. 5± 4. 2± 3. 7% SK-III -4. 2± 2. 7± 0. 7% -3. 8± 2. 6± 0. 7% -5. 9± 3. 2± 1. 3% SK-IV -3. 6± 1. 6± 0. 6% -3. 3± 1. 5± 0. 6% -4. 9± 1. 8± 1. 4% combined -3. 3± 1. 0± 0. 5% -3. 1± 1. 0± 0. 5% -4. 1± 1. 2± 0. 8% non-zero significance 3. 0σ 2. 8σ Rate/Rateaverage expected time variation as a function of cosθz 2. 8σ preliminary α : day-night asym. scaling factor Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 49

exponential parameterization Solar+Kam. LAND sin 2θ 12=0. 308 Δm 221=7. 50 x 10 -5 e. V 2 Solar sin 2θ 12=0. 311 Δm 221=4. 85 x 10 -5 e. V 2 ✓SK spectrum, red : exponential, green : quadratic preliminary Hiroyuki Sekiya TAUP 2015 Torino September 7 2015 50

Comparison with others SNO Kam. LAND Super-K BOREXINO Super-K spectrum is the most precise! Hiroyuki Sekiya TAUP 2015 Torino September 51 7 2015

p+p➝d+e++ νe p+e (99. 77%) +p➝d+νe (0. 23%) d+p➝ 3 He+ γ Solar Neutrinos all solar BOREXINO pp Pee BOREXINO pep MSW (solar&KL) MSW (solar) SK & SNO 3Ηe+α➝ 7 Be+γ 15. 08% 3 3Ηe➝α+2 p Ηe+ 3 He+p➝α+e++ 84. 92% Cl νe 7 Be+e-➝ 7 Li+ν e Be+p➝ 8 B+γ 99. 9% 7 8 B 7 Be 0. 1% BOREXINO Hep 8 B+➝ 8 Be*+e+ +νe 7 Li+p➝α+α; 8 Be*➝α+α Hiroyuki Sekiya TAUP 2015 Torino September 7 2015