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Nucleon Decay Search with LENA

Nucleon Decay Search with LENA. DOANOW 07 Honolulu, Hawaii M. Wurm Technische Universität München, Germany mwurm@ph.tum.de http://www.e15.physik.tu-muenchen.de/research/lena.html. THE LENA DETECTOR AN OVERVIEW. 100m. 30m. LENA Overview. TU München. Michael Wurm. DETECTOR DIMENSIONS

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Nucleon Decay Search with LENA

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  1. Nucleon Decay Searchwith LENA DOANOW 07Honolulu, HawaiiM. WurmTechnische Universität München, Germanymwurm@ph.tum.de http://www.e15.physik.tu-muenchen.de/research/lena.html

  2. THE LENA DETECTOR AN OVERVIEW 100m 30m LENA Overview TU München Michael Wurm DETECTOR DIMENSIONS inner detector- 50kt of organic liquid scintillator (Ø 26m)- 13,500 photomultipliersouter muon veto- water Čerenkov detector- 2m of active shielding LOCATION - mine or deep see plateau- depth of 4,000 m.w.e. to reducem-&cosmogenic background proton decaysolar neutrinosterrestrial neutrinosatmospheric neutrinos artificial neutrino sources supernova neutrinosdiffuse SN neutrino backgroundPHYSICS GOALS

  3. LENA OVERVIEWALTERNATIVE CONFIGURATIONS 3 detectors à 25ktplus storage tanksimpler repair & servicedetector permanently online LENA Overview TU München Michael Wurm vertical detectorcheaper excavationavoids bouyant forces

  4. LENA OVERVIEWANTINEUTRINO SPECTROSCOPY _ various sources emit ne,inverse b-decay allowsprecision measurements:ne + p → n + e+ _ LENA Overview Michael Wurm TU München _ interaction of solar ne’s spin with magnetic fieldscan flip them to ne 5,000 7Be ne per day _ Petcov,Schwetzhep-ph/0607155 _ reactor ne 50-25,000 ev. per year,precision measurementof q12~1%, Dm12~10% Supernova @10kpc: ~9,000 ne eventsmatter effects in SN envelope and earthdiffuse SN neutrinos ~10 ne per year, test ofSNR & SN models _ Hochmuth et al.Astrop.Phys 27, 21hep-ph/0509136 _ terrestial ne ~1,000 eventsper year _ Wurm et al.PRD 75 023007astro-ph/0701305

  5. LAGUNALarge Apparatus for Grand Unificationand Neutrino Astrophysics LENA Overview TU München Michael Wurm 100m 30m coordinated R+D design studyin European collaboration,on-going application for EU funding LENALiquid-Scintillator Detector13,500 PMs for 50 kt of targetwater Čerenkov muon veto MEMPHYSWater Čerenkov Detector500 kt target in 3 shafts,3x 81,000 PMs GLACIERLiquid-Argon Detector100 kt target, 20m drift length, LEM-foil readout28,000 PMs for Čerenkov- and scintillation light

  6. COLLABORATING INSTITUTES APC, Paris,France CEA, Saclay,France CPPM, IN2P3-CBRS, Marseille,France CUPP, Pyhäsalmi,Finland ETHZ, Zürich,Switzerland Institute for Nuclear Research, Moscow,Russia IPNO, Orsay,France LAL, IN2P3-CNRS, Orsay,France LPNHE, IN2P3-CNRS, Paris,France MPI-K Heidelberg,Germany Max Planck für Physik, München,Germany Technische Universität München,Germany Universidad de Granada, Spain Universität Hamburg,Germany University of Bern,Switzerland University of Helsinki,Finland University of Jyväskylä,Finland University of Oulu,Finland University of Padova,Italy University of Silesia, Katowice,Poland University of Sheffield,UK LAGUNADETECTOR LOCATIONS LENA Overview TU München Michael Wurm

  7. PROTON DECAYTHE PARTICLE ZOO Mesons (qq)Q mp+ – ud +1 140 MeVp0 – uu/dd 0 135 MeVK+ – us +1 494 MeV… _ _ _ _ Proton Decay TU München Michael Wurm POINTLIKE PARTICLES COMPOSITE PARTICLES QuarksQ mup +2/3 1.5-3 MeVdown -1/3 3-7 MeVstrange -1/3 95 MeVcharm +2/3 1.25 GeVbottom -1/3 4.5 GeVtop +2/3 174 GeV Hadrons (qqq)Q m proton – uud +1 938 MeVneutron – udd 0 940 MeVL0 – uds 0 1.12 GeV… _ Leptons Q melectron -1 511 keVmuon -1 106 MeVtauon -1 1777 MeVneutrinos (e,m,t) 0 < 2 eV Q – electric charge (in units of e)m – mass (c=1)

  8. PROTON DECAYTHEORETICAL PREDICTIONS GUT SU(5) dominant decay mode: p →p0 + e+predicted proton lifetime: t~ 1031 yrscurrent best limit: t≥ 5.4  1033 yrs P K+ P p0 _ e+ n Supersymmetry (SUSY) dominant decay mode: p → K+ + npredicted proton lifetime: t≤ 1035 yrscurrent best limit: t≥ 2.3  1033 yrs _ Supergravity (SUGRA) dominant decay modes: p →p+ + n (65.7%)p → K+ + n (33.5%) _ _ Proton Decay Michael Wurm TU München Physics beyond the Standard Model usually require the proton to decay …

  9. PROTON DECAY SIMULATION INGEANT4 Proton Decay TU München Michael Wurm _ 104 p→K+n events were simulatedin LENA using the GEANT4 toolkit,implementing detector physics …SCINTILLATOR MODEL light yield 110pe/MeVexcitation decay times 3.4ns, 17nsabsorption length 12mscattering length 60m quenching (Birks‘ formula)PHOTOMULTIPLIERS coverage 30%quantum efficiency 17%time jitter ~1ns by Teresa Marrodán Undagoitia,PRD 72 (2005) 075014

  10. PROTON DECAYSCINTILLATOR TESTS Proton Decay TU München Michael Wurm SOLVENT feasible candidates- purified PXE- 20/80 mixture of PXE/Dodecane- LABall provide attenuation length of >10m @430nm but light yield, scattering length and number of free protons are also important parametersWAVELENGTH SHIFTERS - fluorescence times and therefore time resolution currently under investigation- secondary shifter like bisMSB is needed for emission at 430nm- maybe new shifters with large Stoke‘s shift? scatteringlength fluorescence time attenuationlength light yield

  11. PROTON DECAY EVENT SIGNATURE P K+ 21.13% _ _ _ _ K+ K+ p0 p+ nm nm nm ne n m+ g g Proton Decay Michael Wurm TU München leaves the detectorunnoticed … 1st signal Ekin = 105MeVt = 12.8ns 63.43% Ekin = 110MeVt = 84ns Ekin = 152MeVt = 2.2µs Ekin = 128MeVt = 26ns m+ 2nd signal e+

  12. PROTON DECAY EVENT SIGNATURE Proton Decay TU München Michael Wurm Kaon decay after 18ns Challenge:short decay time of the Kaon (12.8ns) Kaon decay after 5ns

  13. BACKGROUND SOURCES ATMOSPHERIC NEUTRINOS Proton Decay TU München Michael Wurm Kaon decay after 5nsdouble stucture hard to seeatmospheric neutrinosnm flux: 4.8×10-2 MeV-1kt-1yr-1CC reaction of nm on target nuclei: nm+AZ→ A(Z+1) +m-fast K+ events are undistinguishable pulse-shape analysiscut on signal rise-time

  14. ATMOSPHERIC NEUTRINOS RISE-TIME ANALYSIS Proton Decay TU München Michael Wurm ... m signal is on average faster in riseefficiency of the time cuteT = 65%background suppression B ~ 5×10-5… Kaon rise-time spread more widely

  15. BACKGROUND SOURCES HADRON PRODUCTION Proton Decay TU München Michael Wurm PION PRODUCTION Calculated background rate: 0.064 per year KAON PRODUCTION

  16. PROTONS OF 12CNUCLEAR EFFECTS Proton Decay TU München Michael Wurm energy window: eE ~ 0.995 BINDING ENERGY S-state: ~ 37 MeVP-state: ~ 16 MeVFERMI MOTION momenta < 250 MeV/cshift and broadening of lines K+m K+p

  17. PROTON DECAY SENSITIVITY IN LENA Proton Decay TU München Michael Wurm protons in LENA: ~1.4×1034detection efficiency: 0.65measuring time: 10yrsbackground rate: 0.64 for current limit from SuperK:t = 2.3×1033yrs 40 events if no event is seen in 10 yrs:t > 4×1034yrs (90% C.L.)

  18. SUMMARY AND OUTLOOK Summary&Outlook TU München Michael Wurm A 50kt detector like LENA will be a multi-purposedetector, contributing to the fields of geo- and astro- physics as well as particle physics. Concerning the search of proton decay, LENA will beable to test the SUSY-predicted decay channel pK++n. Within 10 years of measurement, the current limit couldbe improved by more than a factor of 10, resulting in anew limit of tp > 4×1034 yrs. _

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