Picture - Prof. Dr. Lothar Oberauer.
The Borexino Experiment research team has succeeded in detecting neutrinos from the sun's second fusion process, the Carbon Nitrogen Oxygen cycle (CNO cycle) for the first time. This means that all of the theoretical predictions on how energy is generated within the sun have now also been experimentally verified. The findings are the result of years of efforts devoted to bringing the background sources in the energy range of the CNO neutrinos under control.
The sun generates its energy through the fusion of hydrogen to helium. This occurs in two ways: The majority of the energy, approximately 99 percent, comes from a process of fusion and decay which begins with two hydrogen nuclei and ends with one helium nucleus.
This process is referred to as the pp (proton-proton) chain.
The rest of the energy results from a cycle in which a total of four hydrogen nuclei ultimately combine to form a helium nucleus with the help of carbon, nitrogen and oxygen as catalysts and intermediate products.
In stars larger than our sun the majority of energy generated is generated by this second process, referred to as the CNO process because of the involvement of carbon, nitrogen and oxygen.
[Read more: "Sun model completely confirmed for the first time"]
We interviewed Prof. Dr. Stefan Schönert and Prof. Dr. Lothar Oberauer.
Question #1. What are the discoveries that have lead up to your current work?
Answer: discovery of neutrino oscillations.
Q #2. Why is your research important? What question or challenge were you setting out to address when you started this work?
A.: I think our research is interesting. Whether it is important is not my task to judge.
It is interesting because it connects the smallest with the largest: neutrinos as elementary particles, extremely weakly interacting with matter, tell us about large objects and structures in the universe. In case of Borexino we can see into the heart of our Sun, we understand how it generates energy in detail. In addition we learn about neutrino properties. We learn how they oscillate, which means, that they change their flavour during flight. This is not explained in standard physics, it shows us the way to physics beyond the standard model.
Q #3. What do you want to achieve with your research?
A.: We would like to contribute to solve some of the most urgent questions in astroparticle physics.
Q #4. What happens next in the process of discovery?
A.: We are working on different projects in the field of astroparticle physics. There are several open questions still to be answered in neutrino physics. Just a few examples: What is the nature of neutrinos? What is their absolute mass scale? Can they show us the way to solve the mystery, why there is the matter- antimatter asymmetry in our universe? And there are many other open questions.