Transcript Slide 1

Super-Kamiokande –
Neutrinos from MeV to TeV
Mark Vagins
University of California, Irvine
EPS/HEP2005 - Lisbon
July 22, 2005
The Collaboration
1 Kamioka Observatory, ICRR, Univ. of Tokyo, Japan
2 RCCN, ICRR, Univ. of Tokyo, Japan
3 Boston University, USA
4 Brookhaven National Laboratory, USA
5 University of California, Irvine, USA
6 California State University, Dominguez Hills, USA
7 Chonnam National University, Korea
8 Duke University, USA
9 George Mason University, USA
10 Gifu University, Japan
11 University of Hawaii, USA
12 Indiana University, USA
13 KEK, Japan
14 Kobe University, Japan
15 Kyoto University, Japan
16 Los Alamos National Laboratory, USA
17 Louisiana State University, USA
18 University of Maryland, College Park, USA
19 University of Minnesota, Duluth, USA
20 Miyagi University of Education, Japan
21 SUNY, Stony Brook, USA
~140 collaborators
22 Nagoya University, Japan
23 Niigata University, Japan
34 institutions
24 Osaka University, Japan
25 Seoul National University, Korea
4 countries
26 Shizuoka Seika College, Japan
27 Shizuoka University, Japan
(as of Jan. 2005)
28 Sungkyunkwan University, Korea
29 RCNS, Tohoku University, Japan
30 University of Tokyo, Japan
+Tsinghua Univ.,
31 Tokai University, Japan
32 Tokyo Institute for Technology, Japan
China
33 Warsaw University, Poland
(June, 2005~)
34 University of Washington, USA
The Location
SuperKamiokande
４１．４ｍ
The Detector
４０ｍ
50000 tons ultra-pure water
22500 tons fiducial volume
1 km overburden = 2700 m.w.e.
SK-I: 40% PMT Coverage
April 1996  July 2001
SK-II: 19% PMT Coverage
December 2002  September 2005
The Neutrino Sources
Solar (Low E)
5 MeV  20 MeV
Atmospheric (High E)
100 MeV  10 TeV+
Pmm = 1 –
sin22qsin2(1.27
Dm2L
)
E
8B
n’s
hep n’s
SK-I: 5 MeV
SK-II: 7 MeV
SK-III: 4 MeV
12 MeV
solar n
Result of n-e
elastic
scattering:
points back
in solar
direction
603 MeV
atmospheric
muon n
Note sharp
edge of ring
from muon
produced by
nm-nucleon
interaction
492 MeV
atmospheric
electron n
Note diffuse
edge of ring
from electron
produced by
ne-nucleon
interaction
Tau n candidate event (~3 GeV)
(Still Fully Contained)
Upward-Going Muons
Upward-going
atmospheric
n-induced
muon
Note activity
in outer
detector:
not contained
Parent n energy between 2 GeV and 40 TeV!
Atmospheric n Results
1489 days of data
No Oscillation
(sin22q23=1.0, Dm223=2.5X10-3 eV2)
627 days of data
No Oscillation
(sin22q23=0.98, Dm223=3.1X10-3 eV2)
Solar n Results
PLB539 (2002) 179
SK-I: 8B Solar Neutrino Flux
May 31, 1996 – July 15, 2001
(1496 days )
Electron total energy: 5.0-20MeV
22400  230
solar n events
8B
flux = 2.35  0.02  0.08 [x106/cm2/s]
Data / SSMBP2004 = 0.406 0.004(stat.) +0.014 -0.013 (syst.)
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
ADN=
(Day-Night)
(Day+Night)/2
=
+0.024
0.014+/-0.049(stat.) - 0.025
(sys.)
Preliminary
+0.013
SK-I D/N Asymmetry: -0.021+/-0.020 - 0.012
SK-I: Energy Spectrum
Energy correlated systematic error
No strong distortion seen
SK-II: Energy Spectrum
12
Oscillation parameters from solar neutrino and
KamLAND experiments (SK-I data only)
99.73%
95%
Solar+KamLAND
KamLAND
Solar
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…
Beacom & Vagins,
PRL93 (2004)171101
Next Up:
• Drain Super-Kamiokande-II and Restore 40% PMT Coverage
• Resume Data-Taking with SK-III by June 2006
L/E Analysis
L/E Analysis Motivation
q
L
Path
length
E
Neutrino
energy
Neutrino oscillation :
Pmm
Neutrino decay :
Pmm
Neutrino decoherence :
Pmm
Use only high resolution L/E events
Dm2L
=1–
)
E
= (cos2q + sin2q x exp(– m L ))2
2t E
1
= 1 – sin22q x (1 – exp(–g0 L ))
2
E
sin22qsin2(1.27
A first dip can be observed
L/E Distribution
1489.2 days FC+PC
Null oscillation
MC
Best fit
expectation w/
systematic errors
Best-ft expectation
First dip is seen as expected
by neutrino oscillation
Test for neutrino decay & neutrino decoherence
Oscillation
Decay
Decoherence
c2min=37.9/40 d.o.f
c2min=49.1/40 d.o.f  Dc2 =11.3
c2min=52.4/40 d.o.f  Dc2 =14.5
Dc2 =11.4 for n decay
 3.4 s
Dc2 =14.6 for n decoherence
 3.8 s
The first dip the data cannot
be explained by other models
Comparison of the allowed parameter regions
between zenith angle analysis and L/E analysis
90% allowed regions
L/E analysis
Zenith angle analysis
K2K
Soudan 2
MACRO
Mass Varying Neutrinos (MaVaN)
Tau Appearance
Likelihood Analysis
Partially Polarized Distribution
Result:
a = 1.82 ± .61
b = 0.96
Expected #:
35.2
fitted #:
64 ± 21
Signal Eff: 44%
Total number
of tau = 145
(total exp’d =79)
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 ne’s…
KamLAND’s
first 22
months of
data
GADZOOKS!
GADZOOKS! will collect this much reactor neutrino data in two weeks.
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…