Constraint on the Majorana nature of neutrino using solar neutrinos

We propose to probe the Majorana nature of electron neutrinos by searching the neutrino type inverse $\beta$ decay. The intense solar neutrino flux makes such experiments practical. We estimate that a liquid scintillator detector with practical scale can collect statistically significant data within about one year of operation and address the question of whether neutrinos are Majorana particles. We examine the public results from the Borexino experiment and find the results reject the Majorana hypothesis of electron neutrinos with a significance of much greater than $5\sigma$ (five standard deviations).