Super-Kamiokande – Neutrinos from MeV to TeV

Mark Vagins

University of California, Irvine

EPS/HEP2005 - LisbonJuly 22, 2005

The Collaboration

1 Kamioka Observatory, ICRR, Univ. of Tokyo, Japan2 RCCN, ICRR, Univ. of Tokyo, Japan3 Boston University, USA4 Brookhaven National Laboratory, USA5 University of California, Irvine, USA6 California State University, Dominguez Hills, USA7 Chonnam National University, Korea8 Duke University, USA9 George Mason University, USA10 Gifu University, Japan11 University of Hawaii, USA12 Indiana University, USA13 KEK, Japan14 Kobe University, Japan15 Kyoto University, Japan16 Los Alamos National Laboratory, USA17 Louisiana State University, USA

18 University of Maryland, College Park, USA19 University of Minnesota, Duluth, USA20 Miyagi University of Education, Japan21 SUNY, Stony Brook, USA22 Nagoya University, Japan23 Niigata University, Japan24 Osaka University, Japan25 Seoul National University, Korea26 Shizuoka Seika College, Japan27 Shizuoka University, Japan28 Sungkyunkwan University, Korea29 RCNS, Tohoku University, Japan30 University of Tokyo, Japan31 Tokai University, Japan32 Tokyo Institute for Technology, Japan33 Warsaw University, Poland34 University of Washington, USA

~140 collaborators 34 institutions 4 countries

(as of Jan. 2005)

+Tsinghua Univ., China(June, 2005~)

Super-Kamiokande

The Location

４０ｍ

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The Detector 50000 tons ultra-pure water

1 km overburden = 2700 m.w.e.

22500 tons fiducial volume

SK-I: 40% PMT Coverage SK-II: 19% PMT Coverage

April 1996 July 2001 December 2002 September 2005

The Neutrino Sources

Solar (Low E) Atmospheric (High E)

5 MeV 20 MeV 100 MeV 10 TeV+P = 1 – sin22sin2(1.27 )

m2L

E

8B ’s

hep ’s

SK-I: 5 MeV

SK-II: 7 MeV

SK-III: 4 MeV

12 MeVsolar

Result of -eelastic

scattering:points back

in solardirection

603 MeVatmospheric

muon

Note sharpedge of ringfrom muon

produced by-nucleoninteraction

492 MeVatmosphericelectron

Note diffuseedge of ring

from electronproduced bye-nucleoninteraction

Tau candidate event (~3 GeV)

(Still Fully Contained)

Upward-Going Muons

Upward-goingatmospheric induced

muon

Note activityin outer

detector: not contained

Parent energy between 2 GeV and 40 TeV!

Atmospheric Results

No Oscillation(sin2223=1.0, m2

23=2.5X10-3 eV2)

1489 days of data

No Oscillation(sin2223=0.98, m2

23=3.1X10-3 eV2)

627 days of data

Solar Results

SK-I: 8B Solar Neutrino Flux

8B flux = 2.35 0.02 0.08 [x106/cm2/s] 　　Data / SSMBP2004 = 0.406 0.004(stat.) +0.014 -0.013 (syst.)

22400 230

solar events

PLB539 (2002) 179

Electron total energy: 5.0-20MeV

May 31, 1996 – July 15, 2001 (1496 days )

Data / SSMBP2000 = 0.465 0.005(stat.) +0.016 -0.015 (syst.)

SK-II: 8B Solar Neutrino Flux

SK-I 8B flux = 2.35 0.02 0.08 [x106/cm2/s] 　　

Seasonal Variation: SK-I + SK-II

SK-I Day / Night Variation

ADN=(Day-Night)

(Day+Night)/2

SK-II Day / Night asymmetry

= 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: Energy Spectrum

Energy correlated systematic error

No strong distortion seen

SK-II: Energy Spectrum

Oscillation parameters from solar neutrino and KamLAND experiments (SK-I data only)

Solar 95%

99.73% KamLAND

Solar+KamLAND

12

12

Ongoing Work:

• ATM MaVaN Analysis for SK-I/II• ATM L/E Analysis for SK-II• Solar SK-II Oscillation Analysis• Three Flavor Analyses • Improved Relic Supernova Neutrino Analysis• Tau Appearance Paper (soon!)• Full SK-I Solar Paper (very soon!) • Gadolinium Enrichment Studies for SK-III• Many others…

Next Up:

• Drain Super-Kamiokande-II and Restore 40% PMT Coverage• Resume Data-Taking with SK-III by June 2006

Beacom & Vagins,

PRL93 (2004)171101

L/E Analysis

L/E Analysis Motivation

E

Path length

L

Neutrino energy

Use only high resolution L/E events

A first dip can be observed

P = (cos2sin2x exp(– ))2m2

Neutrino oscillation :

P = 1 – sin22sin2(1.27 )

m2LE

Neutrino decoherence :

P = 1 – sin22 x (1 – exp(–))

21

Neutrino decay :

LELE

L/E Distribution

Null oscillation MC

Best-ft expectation

1489.2 days FC+PC

First dip is seen as expected by neutrino oscillation

Best fit expectation w/ systematic errors

Test for neutrino decay & neutrino decoherence

Oscillation

Decay

Decoherence

2min=37.9/40 d.o.f

2min=49.1/40 d.o.f 2 =11.3

2min=52.4/40 d.o.f 2 =14.5

2 =11.4 for decay

3.4

2 =14.6 for decoherence

3.8

The first dip the data cannot be explained by other models

Comparison of the allowed parameter regionsbetween zenith angle analysis and L/E analysis

L/E analysis

Zenith angle analysis

K2K

Soudan 2

MACRO

90% allowed regions

Mass Varying Neutrinos (MaVaN)

Tau Appearance

Result: a = 1.82 ± .61b = 0.96

Expected #:35.2 fitted #:64 ± 21 Signal Eff: 44%Total number of tau = 145(total exp’d =79)

Partially Polarized Distribution

Likelihood Analysis

GADZOOKS!

Here’s what the coincident signals in Super-K with GdCl3 will look like (energy resolution is applied):

Oh, and as long as we’re collecting e’s…

GADZOOKS!

GADZOOKS! will collect this much reactor neutrino data in two weeks.

KamLAND’s first 22

months of data

Hyper-K with GdCl3 will collect six KamLAND years of data in one day!

This summer I’ll employ some excellent large-scale hardware to find out if the GdCl3 technique will work:

K2K’s 1 kiloton tank will be used for “real world” studies of

• Gd Water Filtering – UCI built and maintains this water system • Gd Light Attenuation – using real 20” PMTs• Gd Materials Effects – many similar detector elements as in Super-K

We are nearly ready for this effort…