Hunting up low-mass bosons from the Sun using HPGe detector

Abstract In this experiment we aim to look for keV-mass bosons emitted from the Sun, by looking at a process analogous to the photoelectric/Compton effect inside the HPGe detector. Their coupling to both electrons and nucleons is assumed. For masses above 25 keV, the mass dependence of our limit on the scalar-electron coupling reveals a constraint which proves stronger than that obtained recently and based on the very good agreement between the measured and predicted solar neutrinoflux from the 8 B reaction. On the other hand, the mass dependence of our limit on the scalar-proton/electron coupling together entails a limit on a possible Yukawa addition to the gravitational inverse square low. Such a constraint on the Yukawa interactionsproves much stronger than that derived from the latest AFM Casimir force measurement.