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
41.4m
40m
41.4m
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…