Updated Geoneutrino Measurement with the Borexino Detector

Geoneutrinos are electron antineutrinos and neutrinos emitted in the radioactive decays from theEarth’s interior. Due to the intrinsic dependence of the geoneutrino flux and the heat producedin the radioactive decays, geoneutrinos contribute uniquely to our knowledge about the Earth.The main goal of neutrino geophysics is to use the obtained geoneutrino signals in estimating theabundance and distribution of the heat producing elements such as 238U, 235U, 232Th and 40K.The radiogenic heat contribution, especially the mantle contribution to the total surface heat fluxand the nature of the mantle still remain as open questions. The combination of the total geoneutrino flux (≈106cm−2s−1) and the weak interaction cross section (≈10−42 cm−2s−1) lead to hugestatistical uncertainties in the current measurements. This has made the study of geoneutrinosquite challenging and so far, only two detectors, namely KamLAND and Borexino, have measuredgeoneutrinos.The Borexino Detector located at the Laboratori Nazionali del Gran Sasso (LNGS), Italy firstobserved geoneutrinos in 2010 followed by two measurements in 2013 and 2015. The latest geoneutrino measurement included a 5.9σ evidence of geoneutrinos and the rejection of the null hypothesisof the mantle signal at a 98% C.L. The uncertainty in the latest published result is 26.2%. Thiswork concentrates on the further improvement of the geoneutrino measurement. The increasedstatistics and the optimised selection cuts used for the analysis have made it possible to reduce theuncertainty to 20.6%. An uncertainty of less than 20% can be achieved by the further optimisationof the selection cuts and needs more investigation