Takaaki Kajita

ICRR, Univ. of Tokyo

Nufact05, Frascati, June

2005

◆New solar neutrino data from SNO and neutrino oscillations

◆New atmospheric neutrino data from Super-K and neutrino oscillations

SNO collab nucl-ex/0502021Also, M.Chen ENTApP2005

History of SNOHistory of SNO1999 2000 2001 2002 2003 2004 2005 2006

Pure D2O

Salt3He Counters

NOW

?

(1)e++de-+p+p (CC)

(also compared with SK +e+e)

(2)xdxpn, n+dt+(6.25MeV) (NC)

& e+de-+p+p (CC)

(3)x+dx+p+n, n+35Cl36Cl+’s(8.6MeV) (NC)

& e+de-+p+p (CC)

(4) New!New! Same as (3), but with improved stat. and syst.

(1)(2)

(3)(4)

391-day salt phase flux measurements391-day salt phase flux measurements

CC(e) = 1.68 (stat.) (syst.) × 106 cm−2s−1

ES(x) = 2.35 (stat.) (syst.) × 106 cm−2s−1

NC(x) = 4.94 (stat.) (syst.) × 106 cm−2s−1

+0.06

−0.06

+0.08

−0.09

+0.22

−0.22

+0.15

−0.15

+0.21

−0.21

+0.38

−0.34

vertex cossun ~ isotropy

029.0031.0023.0340.0

NC

CC

※The previous number based

on 254days salt data was: 0.306±0.026±0.024.

w/o 8B energy constraint

ee and ( and (++) fluxes) fluxes

SSM 68%CL

SNO NC 68%CL

SNO NC 68%CL

SNO CC68%CL

SNO CC68%CL SNO ES

68%CL

SNO ES68%CL SK ES

68%CL

SK ES68%CL

All the data are consistently explained within the standard oscillationAll the data are consistently explained within the standard oscillation

Comparison of results from SNO-DComparison of results from SNO-D22O O

phase and SNO-salt phasephase and SNO-salt phase

Pure D2O

Salt phase

Salt phase

CC spectrum constrained

Un-constrained

CCCC NCNC

New day-night results from the salt-phaseNew day-night results from the salt-phase

ANC=0 not required, E spectrum unconstrained:

ACC= -0.056±0.074±0.053

ANC=0 required, E spectrum constrained:

ACC= -0.015±0.058±0.027ACC(%)

AN

C(%

)A = 2(N-D) / (N+D)

LMA prediction = +2.7%

Combined result with the pure D2O ACC(=0.070±0.049+0.013-0.012):

ACC(phase-I+II)=+0.037±0.040

Combined result with the Super-K AES (=0.021±0.020+0.012-0.013)

assuming the dilution factor due to and fluxes is 1.55:

ACC(SNO+SK)=+0.035±0.027 consistent with the LMA prediction

Oscillation Analysis with 391-day SaltOscillation Analysis with 391-day Saltglobal solar with new SNO salt

global solar plus latest KamLAND and new SNO salt

SNO collab nucl-ex/0502021 Also many other analyses

Best fit 12=33.9deg. (previous = 32.5deg)

New SK-II dataNew SK-II data

Signal 5482 +132-130 (stat.)7.0 – 20.0 MeV622 days SK-II

Preliminary

SK-II Flux = 2.36 ±0.06 (stat.)+0.16-0.15x 106/cm2/sec

(SK-I flux: 2.35 0.02(stat.) 0.08(sys.) )

Ready to start the physics analysis with the SK-II data.

SK collab. Y.Takeuchi WIN05

= 0.014+/-0.049(stat.) (sys.)ADN=(Day-Night)

(Day+Night)/2

(SK-I D-N asymmetry: -0.021+/-0.020+0.013-0.012)

Preliminary +0.024- 0.025

• SK-I atmospheric neutrino analysis with finer

binning.• Solar term effect and sin223 (SK-I)• Detection of CC interactions (SK-I)• SK-II data and 2 flavor oscillation analysis• SK-II L/E analysis

(preliminary)

SK collab. K.Scholberg, WIN05

SK-I SK-I atmatm analysis with finer binning analysis with finer binning

In the previous atmospheric neutrino analyses in Super-K,

Zenith-angle analysis good for sin22

L/E analysis good for m2

Single analysis that gives best sin22 and m2 ?

Full

oscillation

1/2 osci.

Important energy range to see the oscillation dip = multi-GeV

Finer energy bins for multi-GeV events

Important energy range to see the oscillation dip = multi-GeV

Finer energy bins for multi-GeV events

180 370 bins in (p, zenith, ev-type)180 370 bins in (p, zenith, ev-type)

Expected sensitivities (MC 5yr exposure)Expected sensitivities (MC 5yr exposure)

Zenith-180bin Zenith-370bin

L/E

@(sin22, m2)truth = (1.00, 2.5×10-3)

Zenith-370bin

Allowed region from the finer binning analysisAllowed region from the finer binning analysis

Old zenith-angle analysisL/E analysis

90% CL allowed region:

sin22> 0.93

2.0 < m2 < 3.0×10-3eV2

90% CL allowed region:

sin22> 0.93

2.0 < m2 < 3.0×10-3eV2

(preliminary)

Also consistent with all the other data

KamSoudan-2

K2K

MACRO

s2212=0.825 m212=8.3×10-5

m223=2.5×10-3

sin213=0

Because of the LMA solution, atmospheric neutrinos should also oscillate by (12, m12

2).

)( eP

Oscillation probability is different between s223=0.4 and 0.6 discrimination between 23 >/4 and </4 might be possible by studying low energy atmospheric e and events.

)(

)(

oscnoflux

oscflux

e

e

s223=0.4 =0.5 =0.6

However, due to the cancellation

between e

and e, the

change in the e flux is small.

Peres & Smirnov NPB 680 (2004)

479

Solar term effect to atmospheric Solar term effect to atmospheric

Constraint on sinConstraint on sin222323 with and without the solar terms with and without the solar terms

hep-ph/0408170 found the 2 minimum at sin223=0.46 (Also

E.Lisi this conference) …We need to understand the reason

for this difference.

w/o solar terms

w/ solar terms

Still (almost) maximum mixing is most favored.

(preliminary)

Search forSearch for CCCC eventsevents

CC events

hadrons

● Many hadrons ．．．． (But no big difference with other (NC) events ． )

BAD - likelihood analysis● Upward going only

GOOD Zenith angle

Only ～ 1.0 CC FC events/kton ・ yr

(BG (other events) ～ 130 ev./kton ・ yr)

Only ～ 1.0 CC FC events/kton ・ yr

(BG (other events) ～ 130 ev./kton ・ yr)

hadrons

CC MC

Tau likelihood (or NN) analysisTau likelihood (or NN) analysis Selection Criteria

multi-GeV, multi-ring most energetic ring : e-like log(likelihood) > 0 or NN > 0.5

total visible energy number of ring candidates distance between interaction point and decay-e point max(P) clustered sphericity log(sphericity)

downwarddownward

DATABG-MCtau-MC

Cut

likelihood

upwardupward

MC)

DATABG-MCtau-MC

Cut

likelihood

Num

ber

of e

vent

s

Zenith angle dist. and fit results (prelim., new)Zenith angle dist. and fit results (prelim., new)Likelihood analysis NN analysis

, e, & NC background , e, & NC

background

Data Data ×1.82 MC

×1.93 MC

coszenith coszenith

Nu

mb

er

of e

vent

s

145±48(stat)

+9 / -36 (osc. para. uncertainty)

152±47(stat)

+12 / -27 (osc. para. uncertainty)

79±31(syst) 79±31 (syst)

Fitted # of events

Expected # of events

SK-II atmospheric neutrino dataSK-II atmospheric neutrino dataFC&PC: 627days, Up-going muons: 609days

e-like -like

Allowed osc. parameter regionAllowed osc. parameter region

(preliminary)

SK-II data are consistent with the SK-I data.SK-II data are consistent with the SK-I data.

(preliminary)

(SK-I + II combined analysis: next stage)

SK-II L/E analysisSK-II L/E analysisL/E analysis was carried out for the SK-II data with the identical selection criteria as those in SK-I.

(preliminary)SK-II SK-I

Osc.

Decay

Decoh.

Consistent with SK-I.Oscillation still gives the best fit to the data.

Consistent with SK-I.Oscillation still gives the best fit to the data.

Allowed parameter region based on the Allowed parameter region based on the SK-II L/E analysisSK-II L/E analysis

(preliminary)

SK-II SK-I

SK-II data are consistent with the SK-I data.SK-II data are consistent with the SK-I data.

(SK-I + II combined analysis: next stage)

• New SNO salt result

• New SK(-II) atmospheric neutrino results

• No surprise

• But our knowledge on neutrino masses and mixing angles are improving.

end

Oscillation Analysis Oscillation Analysis

• latest SAGE, final Gallex/GNO, final Cl • SK 1496-day zenith-spectrum • SNO-I (pure D2O) summed spectra day+night

(CC+ES+NC+backgrounds) • SNO-II (391-day salt) extracted CC spectra (day+night), NC and ES

fluxes (day+night) • KamLAND 766 ton-yr results

Input:

Binning for new analysis (=same binning as 3 flavor analysis)

E

Single-Ring

Multi-Ring

Up-stop

Up-through

37 momentum bins x 10 zenith bins = 370 bins in total

Multi-Ring e

Single-Ring e

PC-stop

PC-through

Same as old analysisfiner binning Sample used in 3-flavor

Fewer number of events per bin Poisson statistics to calculate 2

Multi-GeV

Sub-GeV

CC e CC