LAUSR

First, we briefly review the solar abundance problem and its current status. We start with the description of the existing theoretical model of the Sun and its main uncertainties and proceed with the discussion of the observational evidence for the anomaly. We conclude the review part by outlining the main approaches to solving the solar abundance problem investigated before. In the second part of the paper we consider the poorly studied before non-diffusive energy transport solutions to the problem. We calculate the additional energy flux inside the Sun evidenced by the combined data from helioseismology, spectroscopy and solar neutrino detection experiments. Our findings suggest that the solar abundance problem can be solved by a localized loss of energy near the radiative zone boundary and a gain of approximately the same amount of energy inside the solar core ($0.1R_{\odot} \lesssim r \lesssim 0.3R_{\odot}$). We show that if the localized loss of energy is associated with the resonant emission of transversely polarized hidden photons, the kinetic mixing parameter required does not contradict any of the existing constraints, the ones from the Sun being relaxed as long as the energy loss is compensated by energy deposition inside the core. We introduce then the light dark fermions coupled to hidden photons and discuss their interactions with the solar plasma. We find the distribution of these dark particles inside the inner part of the radiative zone which is required to provide the necessary heating of the core.