Kengo Nakamura (Tohoku University) for the Kamland Collaboration
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KamLAND: recent results and future plans Kengo Nakamura (Tohoku university) for the KamLAND collaboration 1 KamLAND Neutrino Program νe from the Sun E<1MeV νe from the Sun E>8MeV Picture from JAEA νe from the Earth E~1MeV νe from Reactors E~5MeV Picture from NASA 2 KamLAND Detector Electronics Hut Inner PMTs Calibration deck 1325 17”PMTs 554 20”PMTs 1200m3 LS 1800m3 BO 20m 3200m3 Water Outer PMTs Cherenkov 225 20” PMTs Outer Detector 20m 3 Past KamLAND results 4 Evidence for reactor neutrino disappearance at 99.95 % CL. LMA Consistent with LMA solution. PDG200 PRL90,021802(2003) 5 Spectral distortion at 99.6 % CL. L0/E oscillatory shape is clearly seen 0 2 2 2 L P(νe→νe) = 1 - sin 2θsin 1.27Δm L0 = 180 km E < > 1.4 2.6 MeV prompt KamLAND data analysis threshold best-fit oscillation PRL 100, 221803 (2008) 1.2 best-fit decay 1 best-fit decoherence o i 0.8 Rat 0.6 0.4 0.2 0 20 30 40 50 60 70 80 L /E (km/MeV) 0 !e PRL94,081801(2005) 2.66 > Eprompt > 0.9 MeV 14 Recent KamLAND result 7 Update from 2005 Increased statistics Longer livetime Lower threshold Improve BG estimation Larger fiducial Combined analysis with Geo neutrinos Reduction of uncertainty Full volume calibration 8 off-axis calibration system Full volume calibration example 60Co in multiple poles Available radioactive sources : Fiducial203Hg uncertainty(0.279 MeV) Cable 1374.7% ➡ 1.8% 60Co in multiple poles Cs (0.661 MeV) 68Ge (0.511 MeV × 2) source 65Zn (1.12 M3V) 60Co (1.173 + 1.333 MeV) AmBe (neutron capture) 210Po13C (13C(α,n)16O bkg.) 9 7 20 4! 2 15 # $ 10 3! 5 2! 1! 1 2 3 4 5 6 ! ! KamLAND ! ! ! ! 95% C.L. 99% C.L. ) 99.73% C.L. 2 10-4 best fit (eV 2 21 m $ Solar 95% C.L. 99% C.L. 2.6 MeV 0.9 MeV 99.73% C.L. best fit Eprompt 10-1 1 10 20 30 40 2 2 tan "12 $# Several years ago: Neutrino scillation??? LMA??? Now: tan2θ12=0.47+0.06-0.05 Δm221=7.59+0.21-0.21×10-5 [eV2] PRL100,221803(2008) 10 A new experiment with KamLAND 11 Δm232=Δm2atm=2.6×10-3 [eV2] Δm221=Δm2sol=7.6×10-5 [eV2] m2 Normal Inverted νe νµ ντ m23 m22 Δm2sol 2 Δm2atm m 1 m22 2 2 Δm atm 2 Δm sol m 1 m23 νe νµ ντ ν =? ν 12 Fiducial size [eV] Part of Heidelberg group 10-1 10-2 !! 10-3 effective majorana mass effective 10-4 10-3 10-2 10-1 [eV] lightest neutrino mass (m1/m3) arXiv:0708.1033 13 FIG. 4 The effective Majorana mass m as a function of the mass of the lightest neutrino, ! ββ" mlightest. In making the plot, we have used the best fit values for the parameters in Table I. The filled areas represent the range possible because of the Majorana phases and are irreducible. If one incorporates the uncertainties in the mixing parameters, the regions widen. See Bilenky et al. (2004) for an example of how the mixing parameter uncertaintyaffects the regions. FIG. 5 The distribution of the sum of electron energies for ββ(2ν) (dotted curve) and ββ(0ν) (solid curve). The curves were drawn assuming that Γ0ν is 1% of Γ2ν and for a 1-σ energy resolution of 2%. 76 Double beta decay experiment at KamLAND miniBalloon R=1.5 m KamLAND balloon R=6.5m Xe 200 kg 136Xe dissolved scintillator KamLAND scintillator Outer Detector 14 Why 136Xe? ~3% dissolved into LS long 2n beta decay life time easy handling KamLAND exists. ultra pure environment (U/Th~10-17 g/g) LS techniques Balloon techniques Reactor/Geo neutrino 15 200kg × 5 years 22 2νBG T1/2(2νββ)>1×10 y <56000 ev/yr m=0.2 eV 10C 0νββ without tagging with tagging QRPA (20 ev/yr) Shell 14 Bi 208Tl QRPA Nucl.Phys.A793(2007)213 Shell Phys.Rev.Lett.100:052503,2008 16 Sensitivity [eV] Part of Heidelberg group 10-1 200 kg 136Xe ➔ 60 meV@5yrs 10-2 !! 10-3 effective majorana mass effective 10-4 10-3 10-2 10-1 [eV] lightest neutrino mass (m1/m3) arXiv:0708.1033 17 FIG. 4 The effective Majorana mass m as a function of the mass of the lightest neutrino, ! ββ" mlightest. In making the plot, we have used the best fit values for the parameters in Table I. The filled areas represent the range possible because of the Majorana phases and are irreducible. If one incorporates the uncertainties in the mixing parameters, the regions widen. See Bilenky et al. (2004) for an example of how the mixing parameter uncertaintyaffects the regions. FIG. 5 The distribution of the sum of electron energies for ββ(2ν) (dotted curve) and ββ(0ν) (solid curve). The curves were drawn assuming that Γ0ν is 1% of Γ2ν and for a 1-σ energy resolution of 2%. 76 Current status We have 50 kg Xe. New electronics is ready. We have started R&D of mini-balloon, design of gas system and infrastructure. 18 KamLAND: precision measurement of neutrino oscillation parameters A new project: KamLAND has just started a new project, 136Xe double beta decay If you are interested in, why don’t you join us? 19 The KamLAND collaboration Study of the Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND S. Abe,1 S. Enomoto,1,2 K. Furuno,1 Y. Gando,1 H. Ikeda,1 K. Inoue,1,2 Y. Kibe,1 Y. Kishimoto,1 M. Koga,1,2 Y. Minekawa,1 T. Mitsui,1 K. Nakajima,1, ∗ K. Nakajima,1 K. Nakamura,1,2 M. Nakamura,1 I. Shimizu,1 Y. Shimizu,1 J. Shirai,1 F. Suekane,1 A. Suzuki,1 Y. Takemoto,1 K. Tamae,1 A. Terashima,1 H. Watanabe,1 E. Yonezawa,1 S. Yoshida,1 A. Kozlov,2 H. Murayama,2,3 J. Busenitz,4 T. Classen,4, † C. Grant,4 G. Keefer,4 D.S. Leonard,4, ‡ D. McKee,4, § A. Piepke,2, 4 T.I. Banks,3 T. Bloxham,3 J.A. Detwiler,3 S.J. Freedman,2,3 B.K. Fujikawa,2, 3 F. Gray,3, ¶ E. Guardincerri,3 L. Hsu,3, ∗∗ K. Ichimura,3 R. Kadel,3 C. Lendvai,3 K.-B. Luk,3 T. O’Donnell,3 H.M. Steiner,3 L.A. Winslow,3, †† D.A. Dwyer,5 C. Jillings,5, ‡‡ C. Mauger,5, §§ R.D. McKeown,5 P. Vogel,5 C. Zhang,5 B.E. Berger,6 C.E. Lane,7 J. Maricic,7 T. Miletic,7 M. Batygov,8 J.G. Learned,8 S. Matsuno,8 S. Pakvasa,8 J. Foster,9 G.A. Horton-Smith,2,9 A. Tang,9 S. Dazeley,10, ¶¶ K.E. Downum,11 G. Gratta,11 K. Tolich,11, ∗∗∗ W. Bugg,12 Y. Efremenko,2,12 Y. Kamyshkov,12 O. Perevozchikov,12 H.J. Karwowski,13 D.M. Markoff,13 W. Tornow,13 K.M. Heeger,2, 14 F. Piquemal,15 J.-S. Ricol,15 and M.P. Decowski2, 16 (The KamLAND Collaboration) 1Research Center for Neutrino Science, Tohoku University, Sendai 980-8578, Japan 2Institute for the Physics and Mathematics of the Universe, Tokyo University, Kashiwa 277-8568, Japan 3Physics Department, University of California, Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 4Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487, USA 5W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA 6Department of Physics, Colorado State University, Fort Collins, Colorado 80523, USA 7Physics Department, Drexel University, Philadelphia, Pennsylvania 19104, USA 8Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA 9Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA 10Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA 11Physics Department, Stanford University, Stanford, California 94305, USA 12Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA 13Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA and Physics Departments at Duke University, North Carolina Central University, and the University of North Carolina at Chapel Hill 14Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA 15CEN Bordeaux-Gradignan, IN2P3-CNRS and University Bordeaux I, F-33175 Gradignan Cedex, France 16Nikhef, Science Park 105, 1098 XG Amsterdam, The Netherlands (Dated: July 1, 2009) Radioactive isotopes produced through cosmic muon spallation are a background for rare event detection in ν detectors, double-beta-decay experiments, and dark-matter searches. Understanding the nature of cos- mogenic backgrounds is particularly important for future experiments aiming to determine the pep and CNO 11 solar neutrino fluxes, for which the background is dominated20 by the spallation production of C. Data from the Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) provides valuable information for bet- ter understanding these backgrounds, especially in liquid scintillator, and for checking estimates from current simulations based upon MUSIC, FLUKA, and Geant4. Using the time correlation between detected muons and neutron captures, the neutron production yield in the KamLAND liquid scintillator is measured to be (2.8 ± 0.3) × 10−4 n/(µ · (g/cm2)). For other isotopes, the production yield is determined from the observed time correlation related to known isotope lifetimes. We find some yields are inconsistent with extrapolations arXiv:0907.0066v1 [hep-ex] 1 Jul 2009 based on an accelerator muon beam experiment. PACS numbers: 96.50.S-,96.60.-j,25.20.-x,25.30.Mr ∗Present address: Center of Quantum Universe, Okayama University, 60510, USA Okayama 700-8530, Japan ††Present address: Department of Physics, Massachusetts Institute of Tech- †Present address: Department of Physics, University of California, Davis, nology, Cambridge, MA 02139, USA California 95616, USA ‡‡Present address: SNOLAB, Lively, ON P3Y 1M3, Canada ‡Present address: Department of Physics, University of Maryland, College §§Present address: Subatomic Physics Group, Los Alamos National Labora- Park, Maryland 20742, USA tory, Los Alamos, NM 87545, USA §Present address: Department of Physics, Kansas State University, Manhat- ¶¶Present address: Lawrence Livermore National Laboratory, Livermore, tan, Kansas 66506, USA ¶ California 94550, USA Present address: Department of Physics and Computational Science, Regis ∗∗∗Present address: CENPA, University of Washington, Seattle, Washington University, Denver, Colorado 80221, USA 98195, USA ∗∗Present address: Fermi National Accelerator Laboratory, Batavia, Illinois.