KamLAND: recent results and future plans. Kengo Nakamura (Tohoku university) for the KamLAND collaboration

Transcription

1 KamLAND: recent results and future plans Kengo Nakamura (Tohoku university) for the KamLAND collaboration 1

2 KamLAND Neutrino Program from the Sun E<1MeV from the Sun E>8MeV Picture from JAEA from the Earth Picture from NASA E~1MeV 2 from Reactors E~5MeV

3 Electronics Hut KamLAND Detector Inner PMTs Calibration deck PMTs PMTs 1800m 3 BO 1200m 3 LS 20m 3200m 3 Water Cherenkov Outer PMTs PMTs Outer Detector 20m 3

4 Past KamLAND results 4

5 Evidence for reactor neutrino disappearance at % CL. Consistent with LMA solution. LMA PRL90,021802(2003) 5 PDG200

6 Spectral distortion at 99.6 % CL MeV prompt analysis threshold KamLAND data best-fit oscillation best-fit decay best-fit decoherence Ratio L 0 /E!e (km/mev) PRL94,081801(2005) 6

7 Recent KamLAND result 7

8 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

9 Full volume calibration example 4.7% 1.8% 9

10 1! ) 2 (ev KamLAND 95% C.L. 99% C.L % C.L. best fit $m MeV 0.9 MeV Eprompt tan 2 Solar " 12 95% C.L. 99% C.L % C.L. best fit Several years ago: Neutrino scillation??? LMA??? Now: tan 2 θ12= Δm 2 21= [ev 2 ] PRL100,221803(2008) 10

11 A new experiment with KamLAND 11

12 Δm 2 32=Δm 2 atm= [ev 2 ] Δm 2 21=Δm 2 sol= [ev 2 ] m 2 Normal Inverted m 2 3 Δm 2 atm e µ τ Δm 2 sol m 2 2 m 2 1 m 2 2 m 2 1 Δm 2 sol e µ τ Δm 2 atm m 2 3 ν =ν? 12

13 Fiducial size [ev] effective majorana mass Part of Heidelberg group [ev] arxiv: lightest neutrino mass (m1/m3) 13

14 Double beta decay experiment at KamLAND miniballoon R=1.5 m Xe 200 kg KamLAND balloon R=6.5m 136Xe dissolved scintillator KamLAND scintillator Outer Detector 14

15 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

16 2νBG <56000 ev/yr 200kg 5 years T1/2(2νββ)> y m=0.2 ev 10 C without tagging with tagging 0νββ QRPA (20 ev/yr) Shell 14 Bi 208 Tl QRPA Nucl.Phys.A793(2007)213 Shell Phys.Rev.Lett.100:052503,

17 Sensitivity [ev] effective majorana mass Part of Heidelberg group 200 kg 136 Xe [ev] arxiv: lightest neutrino mass (m1/m3) 17

18 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

19 KamLAND: precision measurement of neutrino oscillation parameters A new project: KamLAND has just started a new project, 136 Xe double beta decay If you are interested in, why don t you join us? 19

20 The KamLAND collaboration 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 3, L. Hsu, 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 10, S. Dazeley, 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 2, 16 and M.P. Decowski (The KamLAND Collaboration) 1 Research Center for Neutrino Science, Tohoku University, Sendai , Japan 2 Institute for the Physics and Mathematics of the Universe, Tokyo University, Kashiwa , Japan 3 Physics Department, University of California, Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 4 Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487, USA 5 W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA 6 Department of Physics, Colorado State University, Fort Collins, Colorado 80523, USA 7 Physics Department, Drexel University, Philadelphia, Pennsylvania 19104, USA 8 Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA 9 Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA 10 Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA 11 Physics Department, Stanford University, Stanford, California 94305, USA 12 Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA 13 Triangle 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 14 Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA 15 CEN Bordeaux-Gradignan, IN2P3-CNRS and University Bordeaux I, F Gradignan Cedex, France 16 Nikhef, Science Park 105, 1098 XG Amsterdam, The Netherlands (Dated: July 1, 2009) 20