Solar Neutrinos (with a tribute to John. N. Bahcall)

TL;DR

This paper reviews the progress in solar neutrino physics, highlighting Bahcall's contributions, the discovery of neutrino oscillations, and discussing unresolved issues like the solar surface chemical controversy and recent experimental anomalies.

Contribution

It commemorates John Bahcall's pioneering work and summarizes recent advances and unresolved issues in solar neutrino research.

Findings

Confirmation of neutrino flavor oscillations.

Discussion of the solar surface chemical controversy.

Analysis of recent gallium radioactive source experiments.

Abstract

John N. Bahcall championed solar neutrino physics for many years. Thanks to his pioneering and long-lasting contributions, this field of research has not only reached maturity, but has also opened a new window on physics beyond the standard electroweak model through the phenomenon of neutrino flavor oscillations. We briefly outline some recent accomplishments in the field, and also discuss a couple of issues that do not seem to fit in the ``standard picture,'' namely, the chemical controversy at the solar surface, and possible implications of recent gallium radioactive source experiments.