Spectroscopy of geoneutrinos from 2056 days of Borexino data
Phys. Rev. D 92, 031101(R) – Published 7 August 2015
[doi:10.1103/PhysRevD.92.031101] (preprint on arXiv)
This paper have been been highlighted with a Focus story:
“Neutrinos Detected from the Earth’s Mantle”.
We report an improved geoneutrino measurement with Borexino from 2056 days of data taking. The present exposure is (5.5±0.3)×1031 proton×yr. Assuming a chondritic Th/U mass ratio of 3.9, we obtain 23.7+6.5−5.7(stat)+0.9−0.6(sys) geoneutrino events. The null observation of geoneutrinos with Borexino alone has a probability of 3.6×10−9 (5.9σ). A geoneutrino signal from the mantle is obtained at 98% C.L. The radiogenic heat production for U and Th from the present best-fit result is restricted to the range 23–36 TW, taking into account the uncertainty on the distribution of heat producing elements inside the Earth.
In 2015, the Borexino collaboration reported (Physical Review D 92, 031101, 2015) an improved geoneutrino measurement from 2056 days of data taking, with an actual exposure of (5.5 ± 0.3) × 1031 proton-per-year. The null observation of geoneutrinos with Borexino alone was excluded at 5.9.
- bin number (from 0 to 14);
- point central position on the x axis;
- point central position on the y axis;
- error size on the x axis (left and right same values);
- error size on the y axis (bottom and top different values since we used Poisson).
If instead you are looking for the properties of the points used to plot all the curves in the same figure, here you find:
- bin number (from 0 to 356),
- position on the x axis;
- tot = black line, sum of all the components;
- geo = blue dashed line;
- U = blue;
- Th = cyan;
- react = red dashed line;
The data related to all but the geoneutrino curves describe the result of the fit with U and Th kept as free fit parameters. The geoneutrino component instead is the result of a fit in which U and Th were fixed to the chondritic mass ratio.
All fit were performed with an unbinned maximal likelihood.
The energy, expressed in units of photo-electrons p.e. (about 500 p.e./MeV), of all the 77 candidates used in the analysis is instead available here.