The gallium anomaly

Abstract

The Gallium detectors are one of the low energy radiochemical neutrino detectors using 71Ga . They are used to detect the low energy solar (pp) neutrinos. In order to check the overall efficiency of the detectors the calibration experiment were performed using the known neutrino sources. However these calibration experiments results in the anomaly known as ”The Gallium Anomaly” which states that the event rates measured are lower than the expected in the neutrino detection experiment by gallium detectors. We will try to tackle the problem by considering the Neutral current channel in neutrino detection experiment by gallium detectors. The motivation for doing this is because of the lower measured event rate than expected. It means there is a problem for missing neutrinos. The idea is there could be the possibility that may be huge flux of neutrinos are scattered by the nucleus via elastic scattering. Here event rate refers to the germanium counting rate. We first try to understand the problem and tried to look for several reasons that could be the reason for the anomaly. We first try to find the cross-section for elastic neutrino nucleon scattering. However in the real problem we have to deal with the whole nucleus but not only with single nucleon. In order to deal with whole nucleus we used the ”Coherent Elastic Neutrino Nucleus interaction”. We used the coherent elastic channel because the neutrinos produced by source in gallium experiments are of keV range. At these low energy neutrino the coherent elastic scattering dominates.