SN Physics Workshop September 17 th 2009 Michael Smy UC Irvine Super-Kamiokande Results.
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Transcript of SN Physics Workshop September 17 th 2009 Michael Smy UC Irvine Super-Kamiokande Results.
SN Physics Workshop September 17th 2009
Michael SmyUC Irvine
Super-Kamiokande ResultsSuper-Kamiokande Results
Super-KamiokandeSuper-Kamiokande• 50,000 tons of
ultra-pure Water• 11,129 20” PMTs
covering 40% of the inner 32,000 tons: ~six photo-electrons per MeV
• 1,885 8” PMTs with wavelength shifter plates view the outer 18,000 tonsMichael Smy, UC Irvine
Super-Kamiokande HistorySuper-Kamiokande History
11146 ID PMTs(40% coverage)
5182 ID PMTs(19% coverage)
11129 ID PMTs(40% coverage)
EnergyThreshold(total electron energy)
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
SK-I SK-II SK-III SK-IV
Acrylic (front)+ FRP (back)
ElectronicsUpgrade
SK-I SK-II SK-III SK-IV
5.0 MeV 7.0 MeV 4.5 MeVwork in progress
< 4.0 MeVtarget
inner detector mass: 32kton fiducial mass: 22.5kton
Michael Smy, UC Irvine
SK New Front-End Electronics: QBEESK New Front-End Electronics: QBEE
QTC TDC FPGA
Network Interface Card
PMTsignal
EthernetReadout
60MHz ClockTDC Trigger
QTC-Based Electronics with
Ethernet (QBEE)
• 24 channel input• QTC (custom ASIC)
– three gain stages– wider (5x!) dynamic range
• Pipe line processing– multi-hit TDC (AMT3)– FPGA
• Ethernet Readout• 60MHz common clock• Internal calibration pulser• Low (<1W/ch!) power
Calibration Pulser
Michael Smy, UC Irvine
Difference in Readout SystemDifference in Readout System
FormerElectronics
(ATM)
Readout (backplane, SCH, SMP)
Trigger (1.3sec x 3kHz)
HITSUMTrigger
logic
NewElectronics
(QBEE)
Readout (Ethernet)
Periodic trigger(17sec x 60kHz)
Clock
Hardware Triggerusing number of hit
(HITSUM)
1.3secevent window
Variableevent window
by software trigger
No hardware trigger. All hits are read out. Apply software trigger.No hardware trigger. All hits are read out. Apply software trigger.
12PMTsignals
permodule
24PMTsignals
permodule
Collect ALL hits; trigger every 17sec with a 60kHz clock without “gaps”
Former readout system
New readout system
Michael Smy, UC Irvine
SuperSupernova nova Neu-Neu-
trinos trinos
Michael Smy, UC Irvine
Supernova Supernova Burst: Expected # of Events Burst: Expected # of Events
~7,300 e+p events~300 +e events~360 16O NC events ~100 16O CC events (with 5MeV thr.)
for 10 kpc supernova
Neutrino flux and energy spectrum from Livermore simulation (T.Totani, K.Sato, H.E.Dalhed and J.R.Wilson, ApJ.496,216(1998))
Courtesy M. Nakahata, ICRR
Time Variation Measurement withTime Variation Measurement with ee+p+pAssuming a supernova at 10kpc.
Time variation of event rate Time variation of mean energy
Enough statistics to discuss model predictions
ep e+n events give direct energy information (Ee = E – 1.3MeV).
Courtesy M. Nakahata, ICRR
SN at 10kpc
e+p
e+p
e+p e+p
+e +e
+e +e
+e+e Scattering EventsScattering Events
Spectrum of +e events can be statistically extracted using the direction to supernova.
Direction of supernova can be determined with an accuracy of ~5 degree.
Neutrino flux and spectrum from Livermore simulation
Courtesy M. Nakahata, ICRR
SN at 2kpcTime variation Visible energy spectrum
~240,000 events are expected for supernova at 2kpc.
~10,000 events are e scattering events.
Total number of events in parentheses
200 log bins from 20msec to 18sec
Close SupernovaeClose Supernovae
Courtesy M. Nakahata, ICRR
SN at 2kpc
Spectrum measurement up to ~40MeV.
ee++x x Energy Spectrum MeasurementEnergy Spectrum Measurement
Courtesy M. Nakahata, ICRR
SN at 2kpc
Number of events from 20msec to 0.1 sec (1bin=10msec)
Neutronization burst could be observed even with neutrino oscillations.
No oscillation
Normal PH=1 orInverted hierarchy
ν + e -
Normal hierarchy PH=0
Neutronization Burst (eNeutronization Burst (e--+p+pn+n+ee))
Courtesy M. Nakahata, ICRR
Search for Neutronization Burst in SK-I/IISearch for Neutronization Burst in SK-I/II• use magnitude of average
direction of events within 1, 10, and 100ms: sumdir
• 84% efficiency if require sumdir>0.75
• also cut on mean distance between event vertices: >94% efficiency
• no cluster found with more than two events in SK-I or II
• found 194/19/1 doublets within 1/10/100ms in SK-I data while expecting 194/19/2.1
• found 0/0/10 doublets in SK-II data while expecting 0.125/1.25/12.5
Michael Smy, UC Irvine
expect between 1 and six events at 10kpc(depending on oscillation)
a diffuse neutrino signal from all past supernovae
Motivation SRN measurement enables us to investigate the history of past Supernovae. The SRN flux determines the star formation rate and supernova rate in galaxies.
Predicted Predicted SRN fluxSRN flux
Expected # SRN evts in SK10-30MeV: 0.8 -5.0 evts/22.5kt·y
16-30MeV: 0.5 -2.5 evts/22.5kt·y
18-30MeV: 0.3 -1.9 evts/22.5kt·y
Supernova Relic Neutrinos (SRN)Supernova Relic Neutrinos (SRN)
Courtesy Iida, ICRR
Many backgrounds
in SN relic energy
window:• electronic noise• solar ’s • reactor ’s• atmospheric ’s• cosmic ray ’s• spallation from ’s
(~600/day)• radioactive backgrounds
spallation is worst; products decay with energies up to 20.8 MeV
and lifetimes up to 13.8 s (practically forever): spallation limits the
energy threshold & cuts to reduce it causes greatest signal loss
SN Relic SN Relic ’s: ’s: Backgrounds in HBackgrounds in H22OO
atm. → stealth ±→e±
relic ’s
spallation productsfrom cosmic ’s
Michael Smy, UC Irvine
Visible energy [MeV]
SK-ISK-I
Visible energy [MeV]
SK-IISK-II
DATDATAA
Atmospheric e Atmospheric e
Invisible -e decay
Invisible -e decay
Spallation BGSpallation BG
DATDATAA
(1496day) (791day)
preliminarypreliminary preliminarypreliminary
90% C.L. Flux limit:90% C.L. Flux limit:SK-I : < 1.25 /cm2 /sec
SK-I + SK-II : < 1.08 /cm2 /secSK-II : < 3.68 /cm2/sec
Irreducible backgroundsIrreducible backgrounds:Atmospheric νe cc interactions
Decay of sub-Cherenkov ‘invisible μ’s’ from atmospheric νμ interactions
SK-I result:M. Malek, et al, Phys. Rev. Lett. 90, 061101 (2003)
Courtesy Iida, ICRR
0
0.5
1
1.5
2
2.5
3
3.5
4
Constant SN rate
(Totani et al. 1996)
Totani et al. 1997
Malaney et al. 1997)
Hartmann et al. 1997)
Kaplinghat et al. 2004
Ando et al. 2005
Fukugita et al. 2003
Lunardini et al. 2006
SK-II limit = 3.68 /cm2/sec
SK-I limit = 1.25 /cm2/sec Combined limit = 1.08 /cm2/sec
preliminary(E>18MeV)Flux limit VS Predicted FluxFlux limit VS Predicted Flux
Courtesy Iida, ICRR
Solar Solar ‘s‘s
Michael Smy, UC Irvine
Solar Neutrino Future Prospects in SKSolar Neutrino Future Prospects in SK
Vacuum osc. dominant
transition from vacuum to matter osc.“upturn” in 8B relative spectrum.
matter dominant
e survival probability(at best fit parameter)
Expected spectrum distortion with 5 years low BG SK data
BG is 70% reduced compared to SK-I below 5.5 MeVEnergy-cor. Syst. uncertainty is half compared to SK-Ifive years
SK-I
0.8
0.
6
0.
4
0.
2
0.
0
P(
e
e)
Courtesy L. OberauerCourtesy L. OberauerTU MTU Münchennchen(BOREXINO)(BOREXINO)
Neutrino Energy in MeV Michael Smy, UC Irvine
SK-III: Less Radioactive BackgroundSK-III: Less Radioactive Background
r2 [m2]
z [m
]
clean central
13.3kton
5.0-5.5MeV
5.5-6.0MeV
6.0-6.5MeV
SK-ISK-III
SK-ISK-III
SK-ISK-III
Courtesy Y. Takeuchi, ICRR
consistent with SK-I within statistical uncertainty!
Observed Observed 88B Flux in SK-IIIB Flux in SK-III
SK-I 8B flux: 2.35±0.02(stat)±0.08(sys) x106/cm2s(PRD73: 112001, 2006)
DataBest-fitBackground
Courtesy Y. Takeuchi, ICRR
Hint of Signal between 4.5-5.0MeV (recoil electron total energy)
Fiducial volume is central 9.0kton
Solar Peak at 4.5 MeVSolar Peak at 4.5 MeV
DataBest-fitBackground
Courtesy Y. Takeuchi, ICRR
88B B Flux Flux
SK-III 298day5.0-20MeV
(Preliminary)
Michael Smy, UC Irvine
Recoil Electron SpectrumRecoil Electron Spectrum
8B=2.36x106/cm2s
hep=15x103/cm2s(best-fit for SK-I)
Michael Smy, UC Irvine
Day/Night AsymmetryDay/Night Asymmetry• only direct test of matter effects on solar neutrino
oscillations• SK-I measured ADN=2(D-N)/(D+N)=-2.1±2.0%(stat)• SK-I also fit LMA day/night variations; expressed as
ADN the result is ADN=-1.8±1.6%(stat) • SK-II measured ADN=-6.3±4.2%(stat)• SK-III can measure ADN to ±4.3%(stat) with the shown
298 days of data; maybe to ±3.7%(stat) using the entire SK-III data set (including periods w/o SLE or high very low energy background runs)
• SK-I-III can determine ADN to ±1.6%(stat)• SK-I-III can fit LMA D/N variations to ±1.3%(stat) Michael Smy, UC Irvine
Solar Solar Oscillation Constraints Oscillation Constraints
Courtesy Ikeda, ICRR
excluded from spectrum& d/n variation
allowedusing 8B totalflux by SNO
SK combinedVery Preliminary
SK-IIIVery Preliminary
excluded byspectrum
global solarVery Preliminary
WWideband ideband IIntelligent ntelligent TTriggerrigger• have 2 modules:
32 cores • plan to buy four
more modules: 96 cores
• sufficient CPU for 3MeV thresholdI. convert inner detector hit ADC/TDC counts to real times/charges
II. sort hits by time
III. pre-filter based on N230 (# of hits within 230ns)
IV. Software Triggered Online Reconstruction of Events: coincidence after time-of-flight subtraction (vertex from selected four-hit combin.)
V. fast vertex fit
VI. if fiducial, precision vertex fit
VII. if fiducial, save event Michael Smy, UC Irvine
ProCurve Switch
WIT Machine IDual Quad-Core3GHz CPU
WIT Machine IIDual Quad-Core3GHzCPU
10Gbit 10Gbit
1Gbitmany “slow”ethernet lines two fast
ethernet lines
AtmosphericAtmospheric NeutrinosNeutrinos
Michael Smy, UC Irvine
100
0
0
0
010
0
0
0
001
1212
1212
1313
1313
2323
2323 CS
SC
CeS
eSC
CS
SCUi
i
Fanny Dufour WIN09 September 2009
Atmospheric Atmospheric ’s: It’s not just for ’s: It’s not just for atmospheric mixing any moreatmospheric mixing any more
Cij=cosθij
Sij=sinθij
Cij=cosθij
Sij=sinθij
SolarAtmospheric Accelerator / reactor
“2-3 sector” “1-3 sector” “1-2 sector”
Atmospheric mixing parameters:
• Zenith angle analysis → mainly sin2(2θ23)• L/E analysis → mainly Δm2
• Solar term analysis → octant degeneracy
θ13 and mass hierarchy:
• 3 flavors zenith angle analysis
Non-standard interactions are not covered in
this talk
Non-standard interactions are not covered in
this talk
Courtesy F. Dufour, Boston University
Two-Flavor: Zenith & L/E AnalysisTwo-Flavor: Zenith & L/E Analysis
L/E analysisGoal is to actually see the first oscillation dip.
Need events with good path-length (L) and energy (E) resolution.
Uses a subsample of events with good resolution.
cos θzenith
DatasetsSK-I FC/PC: 1489 daysSK-I Upmu: 1646 daysSK-II FC/PC: 798 daysSK-II Upmu: 828 daysSK-III FC/PC: 518 daysSK-III Upmu: 635 days
DatasetsSK-I FC/PC: 1489 daysSK-I Upmu: 1646 daysSK-II FC/PC: 798 daysSK-II Upmu: 828 daysSK-III FC/PC: 518 daysSK-III Upmu: 635 days
420 bins each for SK-I, II, and III; 122 syst. terms describe neutrino flux, cross section, reconstruction,
and data reduction uncertainties
where
Zenith angle analysisGoal is to observe a deficit of upward going neutrinos.
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
Zenith Analysis ResultsZenith Analysis ResultsData
MC (no oscillations)
MC (best fit oscillations)
New:Sub-GeV samples subdivided to improve sensitivity to low energy oscillation effects
16 sub-samples are used for the
oscillation analysis
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
L/E analysis resultsL/E analysis resultsDatasetsSK-I FC/PC μ-like: 1489 daysSK-II FC/PC μ-like: 798 daysSK-III FC/PC μ-like: 518 days
DatasetsSK-I FC/PC μ-like: 1489 daysSK-II FC/PC μ-like: 798 daysSK-III FC/PC μ-like: 518 days
We do see oscillation and not just disappearance and we compare against:
Neutrino decay (disfavored @ 4.4σ)Neutrino decoherence (5.4σ)
Grossman and Worah: hep-ph/9807511Lisi et al.: PRL85 (2000) 1166
Barger et al.: PRD54 (1996) 1, PLB462 (1999) 462
Δm2 = 2.2 * 10-3 eV2Δm2 = 2.2 * 10-3 eV2
sin2(2θ23
)=1.0sin2(2θ23
)=1.0
E
LmP
4sin2sin1)(
22322
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
Two-Flavor Results (SK I+II+III)Two-Flavor Results (SK I+II+III)Zenith angle analysis best fit
L/E analysis best fit
These two analyses are complementary:L/E has stronger Δm2 constraintEqually strong sin22θ23 constraint
These two analyses are complementary:L/E has stronger Δm2 constraintEqually strong sin22θ23 constraint
SK-1+2+3, Preliminary
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
Comparing with MINOS and K2KComparing with MINOS and K2KZenith angle analysis best fit
L/E analysis best fit
SK-1+2+3, Preliminary
The results agree well with other experimentsLong baseline constrains Δm2 betterAtmospheric still has stronger sin2 2θ constraint
The results agree well with other experimentsLong baseline constrains Δm2 betterAtmospheric still has stronger sin2 2θ constraint
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
Solar Term & Octant degeneracySolar Term & Octant degeneracyC
osin
e Z
enit
h A
ngle
Energy (GeV)
νe flux reduction
νe flux enhancement
(In constant density matter)
Driven by Δm212 and θ12.
Addition of solar terms shows no significant deviation of θ23 from π/4.
Addition of solar terms shows no significant deviation of θ23 from π/4.
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
θθ1313 with atmospheric neutrinoswith atmospheric neutrinos
MSW effect gives rise to additional scattering amplitudes in matter (for νe only). The clearest indication of non-zero θ13 at Super-K is a resonance @ ~2-10 GeV for up-going e-like eventsNormal hierarchy neutrino enhancement⇒Inverted hierarchy anti-neutrino enhancement⇒
Analysis uses 3 parameters (sin2θ13, sin2θ23, Δm223)
assuming a single “dominant mass scale” (Δm223 Δm≫ 2
12).
MSW effect gives rise to additional scattering amplitudes in matter (for νe only). The clearest indication of non-zero θ13 at Super-K is a resonance @ ~2-10 GeV for up-going e-like eventsNormal hierarchy neutrino enhancement⇒Inverted hierarchy anti-neutrino enhancement⇒
Analysis uses 3 parameters (sin2θ13, sin2θ23, Δm223)
assuming a single “dominant mass scale” (Δm223 Δm≫ 2
12).
sin2 θ13 = 0.005
Cos
ine
Zen
ith
Ang
le
sin2 θ13 = 0.015 sin2 θ13 = 0.04
Energy (GeV) Energy (GeV) Energy (GeV)
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
Three flavor Effects: Zenith Angle DataThree flavor Effects: Zenith Angle Data
Clear distortion of muon-like zenith distribution, well-described by 2-flavorνμ → ντ disappearance...
Allow also νμ → νe appearance in 3-flavor analysis, look for enhancement of high-energy upward-going e-like events.
No distortion in electron-like samples... No distortion in electron-like samples... no evidence for matter-enhanced no evidence for matter-enhanced ννee appearance.appearance.
Preliminary
Preliminary
Preliminary
Data
MC(no oscillations)
MC (best fit oscillations)
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
Three Flavor ResultsThree Flavor Results
Normal Hierarchy
Inverted Hierarchy
Data consistent with both hierarchies; no electron-like excess observed.Analysis assumes Δm2
12 = 0, next update will include solar terms.
Data consistent with both hierarchies; no electron-like excess observed.Analysis assumes Δm2
12 = 0, next update will include solar terms.
χ2/dof Δm223 sin2θ23 sin2θ13
Normal 469/417 2.1x10-3 0.50 0
Inverted 468/417 2.1x10-3 0.55 0.01
Courtesy F. Dufour, Boston University
Fanny Dufour WIN09 September 2009
By combining the solar term analysis and the three flavor analysis we can get the global pictures: Analysis underway, no results yet.By combining the solar term analysis and the three flavor analysis we can get the global pictures: Analysis underway, no results yet.
Future:Future: The Global PictureThe Global Picture
Courtesy F. Dufour, Boston University
Nucleon DecayNucleon Decay
Michael Smy, UC Irvine
SK-I SK-II
eff.(xBr.) (%)
atm. BG
candi-date
pe+ 44.6 43.5 0.20 0.11 0 0
p+ 35.5 34.7 0.23 0.11 0 0
pe+ 18.8 18.2 0.19 0.09 0 0
p+ 12.4 11.7 0.03 0.01 0 0
pe+ 8.1 7.6 0.08 0.08 0 0
p+ 6.1 5.4 0.30 0.15 0 2
pe+ 4.9 4.2 0.23 0.12 0 0
p+ 1.8 1.5 0.30 0.12 1 0
pe+ 2.4 2.2 0.10 0.04 0 0
p+ 2.8 2.8 0.24 0.07 0 0
pe+ 2.5 2.3 0.26 0.13 1 0
p+ 2.7 2.4 0.10 0.07 0 0
ne+ 19.4 19.3 0.16 0.11 0 0
n+ 16.7 15.6 0.30 0.13 1 0
ne+ 1.8 1.6 0.25 0.13 1 0
n+ 1.1 0.94 0.19 0.10 0 0
Charged lepton + meson modes
SK-I+II
IMB-3
KAM-I+II
exposure(kt ・ yr)
141 7.6 3.8
Total BG 4.7 47.9 11.5
candidates
6 32 9
6 candidates are observed while 4.7 events are expected from atmosphericB.G.For each mode,•p→+(30) : P(≥2)= 7.5%•p→+ : P (≥1)=34.9%•p →+(3) : P (≥1)=32.3%•n →+ : P (≥1)=34.3%•n →e+ : P (≥1)=31.6%no evidence of nucleon decay.
For all modes, efficiency and expected BG for SK-II is almost similar with SK-I,BG expectation is less than 0.5events.Courtesy Kaneyuki, ICRR
K-> Eff (%) BKG Obs.
+ P SK-1 37.0±0.4 188.9±5.7 198±14.1
SK-2 35.7±0.4 95.5±2.0 85± 9.2
Prompt tag
SK-1 7.2±1.6 0.16±0.05 0
SK-2 5.8±1.3 0.08±0.03 0
+0 SK1 6.2±0.5 0.43±0.13 0
SK2 4.8±0.4 0.31±0.10 0
No evidence of p→K+
Merged lifetime limit: 2.8 x1033 years @141 kton ・year(2.3x1033 years@92kton ・ year Phys.Rev.D 72, (2007) 052007)
Efficiency for SK-II are about 80% of SK-I.Expected backgrounds for K+→++prompt , K+→+0
are small.
summary of each analysis
p→K+ mode
Courtesy Kaneyuki, ICRR
Summary of nucleon decay search results
SK-I+II
SK-I+II
SK-I+II
10 34Courtesy Kaneyuki, ICRR
ConclusionsConclusions• still waiting for a galactic core-collapse supernova• still waiting for SN relic neutrinos to show up• SK electronics was upgraded successfully• now read out every hit• SK solar analysis has lower backgrounds <5.5 MeV in the
center of SK, start search for “upturn”• SK-III solar results consistent with SK-I and SK-II results
within statistical uncertainties• SK atmospheric neutrinos still dominate atmospheric
mixing angle constraints and contribute to mass splitting• SK atmospheric neutrinos start to constrain 1-3 mixing• full three-flavor analysis in preparation• SK has not yet found proton decay; sets the best limits