Measurement of Neutrino Oscillation with KamLAND: Evidence of Spectral Distortion

Araki, Tomoaki; Eguchi, K.; Enomoto, S.; Furuno, K.; Ichimura, Kunihiro; Ikeda, H.; Inoue, K.; Ishihara, K.; Iwamoto, Toshiyuki; Kawashima, Tomoyuki; Kishimoto, Y.; Koga, M.; Koseki, Y.; Maeda, Tsuyoshi; Mitsui, Tadao; Motoki, M.; Nakajima, K.; Ogawa, Hiroshi; Owada, K.; Ricol, J. S.; Shimizu, I.; Shirai, J.; Suekane, F.; Suzuki, A.; Tada, Kohei; Tajima, O.; Tamae, K.; Tsuda, Yusuke; Watanabe, Hiroko; Busenitz, J.; Classen, T.; Djurcic, Z.; Keefer, G.; McKinny, K.; Mei, Dongming; Piepke, A.; Yakushev, E.; Berger, B. E.; Chan, Y-D.; Decowski, M. P.; Dwyer, D. A.; Freedman, S. J.; Fu, Y.; Fujikawa, B. K.; Goldman, J.; Gray, F.; Heeger, K. M.; Lesko, K. T.; Luk, K. B.; Murayama, Hitoshi; Poon, A. W. P.; Steiner, H. M.; Winslow, L. A.; Horton-Smith, G. A.; Mauger, C.; McKeown, R. D.; Vogel, P.; Lane, C.; Miletic, T.; Gorham, P. W.; Guillian, G.; Learned, J. G.; Maricic, J.; Matsuno, S.; Pakvasa, Sandip; Dazeley, S.; Hatakeyama, S.; Rojas, Alma D.; Svoboda, R.; Dieterle, B.; Detwiler, J. A.; Gratta, G.; Ishii, K.; Tolich, N.; Uchida, Y.; Batygov, M.; Bugg, W.; Efremenko, Yu.; Kamyshkov, Y.; Kozlov, A.; Nakamura, Yuya; Gould, C. R.; Karwowski, H. J.; Markoff, D. M.; Messimore, J. A.; Nakamura, K.; Rohm, Ryan; Tornow, W.; Wendell, R.; Young, A. R.; Chen, M.J.; Wang, Yifang; Piquemal, F.

doi:10.1103/physrevlett.94.081801

Cited by 1,022 publications

(691 citation statements)

References 17 publications

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“…It has been established as the leading mechanism for flavour transitions in solar [1,2] and atmospheric [3] neutrinos. The typical L/E pattern expected for oscillations begins to emerge from various data sets like the most recent KamLAND data [4,5] or the first generation of long-baseline ν µ disappearance experiments K2K [6,7] and MINOS [8]. The only experiment which cannot be accounted for in a three flavour oscillation framework is the LSND ν e appearance signal [9].…”

Section: Introductionmentioning

confidence: 99%

On the impact of systematical uncertainties for the CP violation measurement in superbeam experiments

Huber¹,

Mezzetto²,

Schwetz³

2008

J. High Energy Phys.

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Superbeam experiments can, in principle, achieve impressive sensitivities for CP violation in neutrino oscillations for large θ 13 . We study how those sensitivities depend on assumptions about systematical uncertainties. We focus on the second phase of T2K, the so-called T2HK experiment, and we explicitly include a near detector in the analysis. Our main result is that even an idealised near detector cannot remove the dependence on systematical uncertainties completely. Thus additional information is required. We identify certain combinations of uncertainties, which are the key to improve the sensitivity to CP violation, for example the ratio of electron to muon neutrino cross sections and efficiencies. For uncertainties on this ratio larger than 2%, T2HK is systematics dominated. We briefly discuss how our results apply to a possible two far detector configuration, called T2KK. We do not find a significant advantage with respect to the reduction of systematical errors for the measurement of CP violation for this setup.

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Section: Introductionmentioning

confidence: 99%

On the impact of systematical uncertainties for the CP violation measurement in superbeam experiments

Huber¹,

Mezzetto²,

Schwetz³

2008

J. High Energy Phys.

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“…An optimistic value of the transition moment, µ = 1 × 10 −11 µ B , was taken. For comparison, the region allowed by the combined analysis of the KamLAND and solar neutrino data [41] is also shown. From [42].…”

Section: Searching For Neutrino Transition Momentsmentioning

confidence: 99%

MSW Oscillations – LMA and Subdominant Effects

Friedland

2011

Nuclear Physics B - Proceedings Supplements

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Preprint: LA-UR-06-6774 Standard LMA solution: basic featuresThe most basic experimental fact about the neutrinos from the Sun is that the electron neutrino survival probability, P std ee ≡ P (ν e → ν e ), is measured to vary as a function of the neutrino energy. At the high end of the spectrum (E ν 6 − 7 MeV) the SNO [2] and Super-Kamiokande [3] experiments have established that P std ee is about ∼ 34 ± 3%. The gallium experiments [4], however, which are sensitive to both high-and low-energy neutrinos, see a higher survival probability: the measured rate is 74 ± 7 SNU, whereas the standard solar model prediction [5] (before oscillations) is 131 +12 −10 . This simple fact has highly non-trivial implications. Indeed, this behavior is not "generic" for mass-induced oscillations, even when they combine with the MSW [6, 7] matter effect. A priori, one might have expected solar neutrinos to be in one of these regimes:• matter dominates at the production point, on the way out of the Sun neutrino flavor evolves adiabatically → constant suppression (regime 1); • matter dominates at the production point, on the way out of the Sun neutrino flavor evolves non-adiabatically → vacuum oscillations -vacuum oscillation length ≪ 1 a.u. (astronomical unit) → oscillations average out → constant observed suppression (regime 2); -vacuum oscillation length ≫ 1 a.u. (astronomical unit) → no time to oscillate → no suppression (regime 3); • vacuum oscillations dominate everywhere, matter effects negligible even in the center of the Sun → oscillations average out → constant observed suppression (regime 4).

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“…is the well known oscillation survival probability formula for antineutrinos from the j th reactor at distance L j , φ j is the reactor flux at the KamLAND detector [30], q f and E f are the relative fission yields and fission energies [21,29]. Following [29], we take…”

Section: Global Fits and Survival Probabilitymentioning

confidence: 99%

“…(4) is also an integral over antineutrino energy. The quantity N is a normalization constant obtained from the total number of events in the absence of antineutrino disappearance above the energy cut at 2.6MeV [21] S(E)dE = 365.2.…”

Section: Global Fits and Survival Probabilitymentioning

confidence: 99%

See 1 more Smart Citation

Two gallium data sets, spin flavour precession and KamLAND

Chauhan¹,

Pulido²,

Picariello

2007

J. Phys. G: Nucl. Part. Phys.

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We reexamine the possibility of a time modulation of the low energy solar neutrino flux which is hinted by the average decrease of the Ga data in line with our previous arguments. We perform two separate fits to solar neutrino data, one corresponding to 'high' and the other to 'low' Ga data, associated with low and high solar activity respectively. We therefore consider an alternative to the conventional solar+KamLAND fitting, which allows one to explore the much wider range of the θ 12 angle permitted by the KamLAND fitting alone. We propose a solution with parameters ∆m 2 21 = 8.4 × 10 −5 eV 2 , tan 2 θ = 0.27 in which the 'high' and the 'low' Ga rates lie far apart and are close to their central values, in contrast to the global best fit solution where these rates lie close to each other. This is an indication that the best fit in which all solar and KamLAND data are used is not a good measure of the separation of the two Ga data, as the information from the low energy neutrino modulation is dissimulated in the wealth of data. Furthermore for the parameter set proposed one obtains an equally good fit to the KamLAND energy spectrum and an even better fit than the 'conventional' LMA one for the reactor antineutrino survival probability as measured by KamLAND.

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Measurement of Neutrino Oscillation with KamLAND: Evidence of Spectral Distortion

Cited by 1,022 publications

References 17 publications

On the impact of systematical uncertainties for the CP violation measurement in superbeam experiments

On the impact of systematical uncertainties for the CP violation measurement in superbeam experiments

MSW Oscillations – LMA and Subdominant Effects

Two gallium data sets, spin flavour precession and KamLAND

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