Independent determination of the Earth's orbital parameters with solar neutrinos in Borexino

TL;DR

Borexino's decade-long high-precision solar neutrino measurements enabled the first direct determination of Earth's orbital eccentricity through neutrino flux modulation, confirming solar neutrino origin and exploring frequency signatures.

Contribution

This work is the first to measure Earth's orbital parameters solely using solar neutrino data from Borexino, demonstrating the experiment's unique sensitivity.

Findings

Detected Earth's orbital eccentricity with >5σ significance

First direct measurement of Earth's orbital parameters via neutrinos

No additional significant modulation frequencies found

Abstract

Since the beginning of 2012, the Borexino collaboration has been reporting precision measurements of the solar neutrino fluxes, emitted in the proton-proton chain and in the Carbon-Nitrogen-Oxygen cycle. The experimental sensitivity achieved in Phase-II and Phase-III of the Borexino data taking made it possible to detect the annual modulation of the solar neutrino interaction rate due to the eccentricity of Earth's orbit, with a statistical significance greater than 5$\sigma$. This is the first precise measurement of the Earth's orbital parameters based solely on solar neutrinos and an additional signature of the solar origin of the Borexino signal. The complete periodogram of the time series of the Borexino solar neutrino detection rate is also reported, exploring frequencies between one cycle/year and one cycle/day. No other significant modulation frequencies are found. The present results were uniquely made possible by Borexino's decade-long high-precision solar neutrino detection.