Limits...
Antineutrino science by KamLAND.

Suzuki A - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2007)

Bottom Line: KamLAND measured the ν̄ e's flux from distant nuclear reactors, and found fewer events than expected from standard assumptions about ν̄ e propagation at the 99.998% confidence level (C.L.).The total observed number of 4.5 to 54.2, assuming a Th/U mass concentration ratio of 3.9 is consistent with 19 predicted by geophysical models.This detection allows better estimation of the abundances and distributions of radioactive elements in the Earth, and of the Earth's overall heat budget.

View Article: PubMed Central - PubMed

Affiliation: Director General, High Energy Accelerator Research Organization, Ibaraki, Japan . ; Director General, High Energy Accelerator Research Organization, Ibaraki, Japan .

ABSTRACT
KamLAND measured the ν̄ e's flux from distant nuclear reactors, and found fewer events than expected from standard assumptions about ν̄ e propagation at the 99.998% confidence level (C.L.). The observed energy spectrum disagrees with the expected spectral shape at 99.6% C.L., and prefers the distortion from neutrino oscillation effects. A two-flavor oscillation analysis of the data from KamLAND and solar neutrino experiments with CPT invariance, yields [Formula: see text] eV(2) and [Formula: see text]. All solutions to the solar neutrino problem except for the large mixing angle (LMA) region are excluded. KamLAND succeeded in detecting geoneutrinos produced by the decays of (238)U and (232)Th within the Earth. The total observed number of 4.5 to 54.2, assuming a Th/U mass concentration ratio of 3.9 is consistent with 19 predicted by geophysical models. This detection allows better estimation of the abundances and distributions of radioactive elements in the Earth, and of the Earth's overall heat budget.

No MeSH data available.


Related in: MedlinePlus

Energy distributions of the expected ν̄e’s from 238U, 232Th and 40K decay chains. The vertical dotted line indicates E = 1.8 MeV,the threshold energy of inverse β-decay.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3756737&req=5

f11-83_027: Energy distributions of the expected ν̄e’s from 238U, 232Th and 40K decay chains. The vertical dotted line indicates E = 1.8 MeV,the threshold energy of inverse β-decay.

Mentions: The 238U and 232Th decays via a series of well established α and β− processes emit 6 and 4 ν̄e’s, respectively. The 40K decays through two branching modes, 89.28% of a β− decay and 10.72% of an electron capture, accompanying ν̄e or νe. The expected ν̄e energy distributions of these decay chains are shown in Fig. 11. KamLAND detects ν̄e’s with E > 1.8 MeV due to the reaction threshold energy of the inverse β-decay, resulting to be sensitive to ν̄e’s from 238U and 232Th.


Antineutrino science by KamLAND.

Suzuki A - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2007)

Energy distributions of the expected ν̄e’s from 238U, 232Th and 40K decay chains. The vertical dotted line indicates E = 1.8 MeV,the threshold energy of inverse β-decay.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756737&req=5

f11-83_027: Energy distributions of the expected ν̄e’s from 238U, 232Th and 40K decay chains. The vertical dotted line indicates E = 1.8 MeV,the threshold energy of inverse β-decay.
Mentions: The 238U and 232Th decays via a series of well established α and β− processes emit 6 and 4 ν̄e’s, respectively. The 40K decays through two branching modes, 89.28% of a β− decay and 10.72% of an electron capture, accompanying ν̄e or νe. The expected ν̄e energy distributions of these decay chains are shown in Fig. 11. KamLAND detects ν̄e’s with E > 1.8 MeV due to the reaction threshold energy of the inverse β-decay, resulting to be sensitive to ν̄e’s from 238U and 232Th.

Bottom Line: KamLAND measured the ν̄ e's flux from distant nuclear reactors, and found fewer events than expected from standard assumptions about ν̄ e propagation at the 99.998% confidence level (C.L.).The total observed number of 4.5 to 54.2, assuming a Th/U mass concentration ratio of 3.9 is consistent with 19 predicted by geophysical models.This detection allows better estimation of the abundances and distributions of radioactive elements in the Earth, and of the Earth's overall heat budget.

View Article: PubMed Central - PubMed

Affiliation: Director General, High Energy Accelerator Research Organization, Ibaraki, Japan . ; Director General, High Energy Accelerator Research Organization, Ibaraki, Japan .

ABSTRACT
KamLAND measured the ν̄ e's flux from distant nuclear reactors, and found fewer events than expected from standard assumptions about ν̄ e propagation at the 99.998% confidence level (C.L.). The observed energy spectrum disagrees with the expected spectral shape at 99.6% C.L., and prefers the distortion from neutrino oscillation effects. A two-flavor oscillation analysis of the data from KamLAND and solar neutrino experiments with CPT invariance, yields [Formula: see text] eV(2) and [Formula: see text]. All solutions to the solar neutrino problem except for the large mixing angle (LMA) region are excluded. KamLAND succeeded in detecting geoneutrinos produced by the decays of (238)U and (232)Th within the Earth. The total observed number of 4.5 to 54.2, assuming a Th/U mass concentration ratio of 3.9 is consistent with 19 predicted by geophysical models. This detection allows better estimation of the abundances and distributions of radioactive elements in the Earth, and of the Earth's overall heat budget.

No MeSH data available.


Related in: MedlinePlus