Particle physics confronts the solar neutrino problem

This review has four parts. In Part 1, we describe the reactions that produce neutrinos in the sun and the expected flux of those neutrinos on the earth. We then discuss the detection of these neutrinos, and how the results obtained differ from the theoretical expectations, leading to what is known as the solar neutrino problem. In Part 2, we show how neutrino oscillations can provide a solution to the solar neutrino problem. This includes vacuum oscillations, as well as matter enhanced oscillations. In Part 3, we discuss the possibility of time variation of the neutrino flux and how a magnetic moment of the neutrino can solve the problem. We also discuss particle physics models which can give rise to the required values of magnetic moments. In Part 4, we present some concluding remarks and an outlook for the near future.