Precision measurement of neutrino oscillation parameters with KamLAND.
The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06.
Abe
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S
Research Center for Neutrino Science, Tohoku University, Sendai 980-8578, Japan.
Ebihara
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T
Enomoto
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Furuno
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Gando
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Ichimura
K
K
Ikeda
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H
Inoue
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Kibe
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Y
Kishimoto
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Y
Koga
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Kozlov
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Minekawa
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Y
Mitsui
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Nakajima
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Nakajima
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Nakamura
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Nakamura
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Owada
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Shimizu
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I
Shimizu
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Shirai
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Suekane
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Suzuki
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Takemoto
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Tamae
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Terashima
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Watanabe
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Yonezawa
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Yoshida
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Busenitz
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Classen
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Grant
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Keefer
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Leonard
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McKee
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Piepke
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Decowski
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Detwiler
J A
JA
Freedman
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SJ
Fujikawa
B K
BK
Gray
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F
Guardincerri
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Hsu
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L
Kadel
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R
Lendvai
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C
Luk
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KB
Murayama
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O'Donnell
T
T
Steiner
H M
HM
Winslow
L A
LA
Dwyer
D A
DA
Jillings
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Mauger
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C
McKeown
R D
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Vogel
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Zhang
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Berger
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Lane
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Maricic
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Miletic
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Batygov
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M
Learned
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JG
Matsuno
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Pakvasa
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S
Foster
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Horton-Smith
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GA
Tang
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A
Dazeley
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S
Downum
K E
KE
Gratta
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Tolich
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K
Bugg
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Efremenko
Y
Y
Kamyshkov
Y
Y
Perevozchikov
O
O
Karwowski
H J
HJ
Markoff
D M
DM
Tornow
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Heeger
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KM
Piquemal
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Ricol
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