Precision measurement of neutrino oscillation parameters with KamLAND
Precision measurement of neutrino oscillation parameters with KamLAND
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DOI：
10.1103/physrevlett.100.221803
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发表时间：
2008-06-06
影响因子：
8.6
通讯作者：
Ricol, J. -S.
中科院分区：
文献类型：
--
作者：
Abe, S.;Ebihara, T.;Ricol, J. -S.
卡姆兰德实验已经确定了中微子振荡参数德尔塔m(21)(2)的精确值和对θ(12)的严格约束。由于更长的寿命和更大的基准体积，核反应堆反中微子的暴露几乎是以前结果的四倍，达到2.44x10(32)质子年。在巴(E)能谱之上的未扭曲反应堆(NU)现在在5西格玛被拒绝。对高于反贝塔衰变能量阈值的反应堆光谱的分析，包括地中微子，给出了德尔塔m(21)(2)=7.58(-0.13)(+0.14)(stat)(-0.15)(+0.15)(syst)x 10(-5)eV(2)和tan(2)theta(12)=0.56(-0.07)(+0.10)(stat)(-0.06)(+0.10)(syst).的最佳匹配在4西格玛时，在较高和较低的增量m(21)(2)处的局部增量极小值是不利的。结合太阳中微子数据，得到了dm(21)(2)=7.59(-0.21)(+0.21)×10(-5)eV(2)和tan(2)theta(12)=0.47(-0.05)(+0.06)。
The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Delta m(21)(2) and stringent constraints on theta(12). The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44x10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor (nu) over bar (e) energy spectrum is now rejected at > 5 sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Delta m(21)(2)=7.58(-0.13)(+0.14)(stat)(-0.15)(+0.15)(syst) x 10(-5) eV(2) and tan(2)theta(12)=0.56(-0.07)(+0.10)(stat)(-0.06)(+0.10)(syst). Local Delta chi(2) minima at higher and lower Delta m(21)(2) are disfavored at > 4 sigma. Combining with solar neutrino data, we obtain Delta m(21)(2)=7.59(-0.21)(+0.21) x 10(-5) eV(2) and tan(2)theta(12)=0.47(-0.05)(+0.06).