SN Physics Workshop September 17 th 2009 Michael Smy UC Irvine Super-Kamiokande Results

Super-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 tons Michael Smy, UC Irvine

Super-Kamiokande History ID PMTs (40% coverage) 5182 ID PMTs (19% coverage) ID PMTs (40% coverage) Energy Threshold (total electron energy) SK-ISK-IISK-IIISK-IV Acrylic (front) + FRP (back) Electronics Upgrade SK-ISK-IISK-IIISK-IV 5.0 MeV7.0 MeV4.5 MeV work in progress < 4.0 MeV target inner detector mass: 32kton fiducial mass: 22.5kton Michael Smy, UC Irvine

SK New Front-End Electronics: QBEE QTCTDCFPGA Network Interface Card PMT signal Ethernet Readout 60MHz Clock TDC Trigger Q TC- B ased E lectronics with E thernet (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 System Former Electronics (ATM) Readout (backplane, SCH, SMP) Trigger (1.3  sec x 3kHz) HITSUM Trigger logic New Electronics (QBEE) Readout (Ethernet) Periodic trigger (17  sec x 60kHz) Clock Hardware Trigger using number of hit (HITSUM) 1.3  sec event window Variable event window by software trigger No hardware trigger. All hits are read out. Apply software trigger. 12PMT signals per module 24PMT signals per module Collect ALL hits; trigger every 17  sec with a 60kHz clock without “gaps” Former readout system New readout system Michael Smy, UC Irvine

Super nova Neu- trinos Michael Smy, UC Irvine

Supernova Burst: Expected # of Events ~7,300 e +p events ~300 +e events ~ O NC  events ~ O 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 with e +p Assuming a supernova at 10kpc. Time variation of event rateTime variation of mean energy Enough statistics to discuss model predictions e p  e + n events give direct energy information (E e = E – 1.3MeV). Courtesy M. Nakahata, ICRR

SN at 10kpc e +p +e +e Scattering Events +e Scattering 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 2kpc Time 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 Supernovae Courtesy M. Nakahata, ICRR

SN at 2kpc Spectrum measurement up to ~40MeV. e + x Energy Spectrum Measurement e + x Energy 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 P H =1 or Inverted hierarchy ν＋e－ν＋e－ Normal hierarchy P H =0 Neutronization Burst (e - +p  n+ e ) Courtesy M. Nakahata, ICRR

Search 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 SRN flux Expected # SRN evts in SK 10-30MeV: evts/22.5kt · y 16-30MeV: evts/22.5kt ·y 18-30MeV: evts/22.5kt ·y 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 ’s: Backgrounds in H 2 O atm.  → stealth  ± →e ± relic ’s spallation products from cosmic  ’s Michael Smy, UC Irvine

Visible energy [MeV] SK-I SK-II DATA Atmospheric e Invisible  -e decay Spallation BG DATA (1496day) (791day) preliminary preliminary 90% C.L. Flux limit: SK-I : < 1.25 /cm 2 /sec SK-I + SK-II : < 1.08 /cm 2 /sec SK-II : < 3.68 /cm 2 /sec Irreducible backgrounds Irreducible backgrounds: Atmospheric ν e cc interactions Decay of sub-Cherenkov ‘invisible μ’s’ from atmospheric ν μ interactions SK-I result: M. Malek, et al, Phys. Rev. Lett. 90, (2003) Courtesy Iida, ICRR

Flux limit VS Predicted Flux Courtesy Iida, ICRR

Solar ‘s Michael Smy, UC Irvine

Solar Neutrino Future Prospects in SK Vacuum osc. dominant transition from vacuum to matter osc. “upturn” in 8 B relative spectrum. matter dominant e survival probability (at best fit parameter) SK-I P( e  e ) Courtesy L. Oberauer TU Mnchen TU München(BOREXINO) Neutrino Energy in MeV Michael Smy, UC Irvine

SK-III: Less Radioactive Background r 2 [m 2 ] z [m] clean central 13.3kton MeV MeV MeV SK-I SK-III SK-I SK-III SK-I SK-III Courtesy Y. Takeuchi, ICRR

consistent with SK-I within statistical uncertainty! Observed 8 B Flux in SK-III SK-I 8 B flux: 2.35±0.02(stat) ± 0.08(sys) x10 6 /cm 2 s (PRD73: , 2006) Data Best-fit Background Courtesy Y. Takeuchi, ICRR

Hint of Signal between MeV (recoil electron total energy) Fiducial volume is central 9.0kton Solar Peak at 4.5 MeV Data Best-fit Background Courtesy Y. Takeuchi, ICRR

8 B Flux SK-III 298day MeV (Preliminary) Michael Smy, UC Irvine

Recoil Electron Spectrum  8 B =2.36x10 6 /cm 2 s  hep =15x10 3 /cm 2 s (best-fit for SK-I) Michael Smy, UC Irvine

Day/Night Asymmetry only direct test of matter effects on solar neutrino oscillations SK-I measured A DN =2(D-N)/(D+N)=-2.1±2.0%(stat) SK-I also fit LMA day/night variations; expressed as A DN the result is A DN =-1.8±1.6%(stat) SK-II measured A DN =-6.3±4.2%(stat) SK-III can measure A DN 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 A DN to ±1.6%(stat) SK-I-III can fit LMA D/N variations to ±1.3%(stat) Michael Smy, UC Irvine

Solar Oscillation Constraints Courtesy Ikeda, ICRR excluded from spectrum & d/n variation allowed using 8 B total flux by SNO SK combined Very Preliminary SK-III Very Preliminary excluded by spectrum global solar Very Preliminary

W ideband I ntelligent T rigger have 2 modules: 32 cores plan to buy four more modules: 96 cores sufficient CPU for 3MeV threshold I.convert inner detector hit ADC/TDC counts to real times/charges II.sort hits by time III.pre-filter based on N 230 (# of hits within 230ns) IV.S oftware T riggered O nline R econstruction of E vents : 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 I Dual Quad-Core 3GHz CPU WIT Machine II Dual Quad-Core 3GHzCPU 10Gbit 1Gbit many “slow” ethernet lines two fast ethernet lines

Atmospheric Neutrinos Michael Smy, UC Irvine

Fanny Dufour WIN09 September 2009 Atmospheric ’s: It’s not just for atmospheric mixing any more C ij =cosθ ij S ij =sinθ ij C ij =cosθ ij S ij =sinθ ij SolarAtmospheric Accelerator / reactor “2-3 sector”“1-3 sector” “1-2 sector” Atmospheric mixing parameters: Zenith angle analysis → mainly sin 2 (2θ 23 ) L/E analysis → mainly Δm 2 Solar term analysis → octant degeneracy θ 13 and mass hierarchy: 3 flavors zenith angle analysis Non-standard interactions are not covered in this talk Courtesy F. Dufour, Boston University

Two-Flavor: Zenith & L/E Analysis L/E analysis Goal 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 θ zenith Datasets SK-I FC/PC: 1489 days SK-I Upmu: 1646 days SK-II FC/PC: 798 days SK-II Upmu: 828 days SK-III FC/PC: 518 days SK-III Upmu: 635 days Datasets SK-I FC/PC: 1489 days SK-I Upmu: 1646 days SK-II FC/PC: 798 days SK-II Upmu: 828 days SK-III FC/PC: 518 days SK-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 analysis Goal is to observe a deficit of upward going neutrinos. Courtesy F. Dufour, Boston University

Fanny Dufour WIN09 September 2009 Zenith Analysis Results Data 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 results Datasets SK-I FC/PC μ -like: 1489 days SK-II FC/PC μ -like: 798 days SK-III FC/PC μ -like: 518 days Datasets SK-I FC/PC μ -like: 1489 days SK-II FC/PC μ -like: 798 days SK-III FC/PC μ -like: 518 days We do see oscillation and not just disappearance and we compare against: Neutrino decay 4.4σ) Neutrino decoherence (5.4σ) Grossman and Worah: hep-ph/ Lisi et al.: PRL85 (2000) 1166 Barger et al.: PRD54 (1996) 1, PLB462 (1999) 462 Δm 2 = 2.2 * eV 2 sin 2 (2θ 23 )=1.0 Courtesy F. Dufour, Boston University

Fanny Dufour WIN09 September 2009 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 Δm 2 constraint Equally strong sin 2 2θ 23 constraint These two analyses are complementary: L/E has stronger Δm 2 constraint Equally strong sin 2 2θ 23 constraint SK-1+2+3, Preliminary Courtesy F. Dufour, Boston University

Fanny Dufour WIN09 September 2009 Comparing with MINOS and K2K Zenith angle analysis best fit L/E analysis best fit SK-1+2+3, Preliminary The results agree well with other experiments Long baseline constrains Δm 2 better Atmospheric still has stronger sin 2 2θ constraint The results agree well with other experiments Long baseline constrains Δm 2 better Atmospheric still has stronger sin 2 2θ constraint Courtesy F. Dufour, Boston University

Fanny Dufour WIN09 September 2009 Solar Term & Octant degeneracy Cosine Zenith Angle Energy (GeV) ν e flux reduction ν e flux enhancement (In constant density matter ) Driven by Δm 2 12 and θ 12. Addition of solar terms shows no significant deviation of θ 23 from π/4. Courtesy F. Dufour, Boston University

Fanny Dufour WIN09 September 2009 θ 13 with atmospheric neutrinos MSW effect gives rise to additional scattering amplitudes in matter (for ν e only). The clearest indication of non-zero θ 13 at Super-K is a ~2-10 GeV for up-going e-like events Normal hierarchy ⇒ neutrino enhancement Inverted hierarchy ⇒ anti-neutrino enhancement Analysis uses 3 parameters (sin 2 θ 13, sin 2 θ 23, Δm 2 23 ) assuming a single “dominant mass scale” (Δm 2 23 ≫ Δm 2 12 ). MSW effect gives rise to additional scattering amplitudes in matter (for ν e only). The clearest indication of non-zero θ 13 at Super-K is a ~2-10 GeV for up-going e-like events Normal hierarchy ⇒ neutrino enhancement Inverted hierarchy ⇒ anti-neutrino enhancement Analysis uses 3 parameters (sin 2 θ 13, sin 2 θ 23, Δm 2 23 ) assuming a single “dominant mass scale” (Δm 2 23 ≫ Δm 2 12 ). sin 2 θ 13 = Cosine Zenith Angle sin 2 θ 13 = sin 2 θ 13 = 0.04 Energy (GeV) Courtesy F. Dufour, Boston University

Fanny Dufour WIN09 September 2009 Three flavor Effects: Zenith Angle Data Clear distortion of muon-like zenith distribution, well-described by 2-flavor ν μ → ν τ disappearance... Allow also ν μ → ν e appearance in 3-flavor analysis, look for enhancement of high-energy upward-going e-like events. No distortion in electron-like samples... no evidence for matter-enhanced ν e appearance. Preliminary Data MC (no oscillations) MC (best fit oscillations) Courtesy F. Dufour, Boston University

Fanny Dufour WIN09 September 2009 Three Flavor Results Normal Hierarchy Inverted Hierarchy Data consistent with both hierarchies; no electron-like excess observed. Analysis assumes Δm 2 12 = 0, next update will include solar terms. Data consistent with both hierarchies; no electron-like excess observed. Analysis assumes Δm 2 12 = 0, next update will include solar terms. χ 2 /dofΔm 2 23 sin 2 θ 23 sin 2 θ 13 Normal 469/4172.1x Inverted 468/4172.1x 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. Future:The Global Picture Future: The Global Picture Courtesy F. Dufour, Boston University

Nucleon Decay Michael Smy, UC Irvine

SK-ISK- II eff. (xBr.) (%) atm. BG candi- date pe+pe+ p+p+ p  e+  p   +  p  e+    p   +    pe+pe+ p+p+ p  e+    p   +    p  e+  p   +  ne+ne+ n+n+ ne+ne+ n+n+ Charged lepton + meson modes SK- I+II IMB- 3 KAM- I+II exposure(kt ・ yr) Total BG candidates candidates are observed while 4.7 events are expected from atmospheric  B.G. For each mode, p→  +  (3  0 ) : 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 (%)BKGObs.  + PP SK-137.0± ±5.7198±14.1 SK-235.7± ±2.0 85± 9.2 Prompt  tag SK-1 7.2± ±0.050 SK-2 5.8± ±0.030 +0+0 SK1 6.2± ±0.130 SK2 4.8± ±0.100 No evidence of p → K + Merged lifetime limit: 2.8 x10 33 kton ・ year (2.3x10 33 ・ year Phys.Rev.D 72, (2007) ) 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 Courtesy Kaneyuki, ICRR

Conclusions 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