Borexino experiment: analysis of ten years of neutrino signals

Researchers from the Borexino collaboration have published the hitherto most comprehensive analysis of neutrinos from the Sun's core processes. The results confirm previous assumptions about the processes inside the sun.

According to the standard solar model, around 99 percent of the Sun's energy stems from a sequence of fusion processes in which hydrogen is converted to helium. It begins with the fusion of two protons into a heavy hydrogen nucleus, a process aptly called the pp chain.

In some of these processes, neutrinos of characteristic energies are also released, allowing the progression of the pp chain to be reconstructed very accurately.

First overall assessment of the Sun's neutrino spectrum
Buried deep in the mountains of the Italian Gran Sasso massif, the Borexino experiment, which focusses on detecting these solar neutrinos, has been running since 2007.

The Borexino scientists are now presenting, for the first time, a comprehensive investigation of the fusion processes in the pp chain via neutrinos. They determined the interaction rates of the individual processes with unprecedented precision.

The results substantiate the solar model
"All in all, the results confirm our theoretical perceptions of what goes on inside the Sun," says Prof. Stefan Schonert, Professor of Experimental Astroparticle Physics and Co-Spokesperson of the Collaborative Research Center 1258 at the Technical University of Munich and member of the new ORIGINS Cluster.

The Borexino scientists also calculated the Sun's energy production rate and compared this to the well-known estimate based on the Sun's electromagnetic radiation. The two values are in good agreement.

This shows that solar activity has been constant for at least one hundred thousand years, which is how long it takes sunlight to leave the energy production zone inside the Sun. Neutrinos, in contrast reach the Earth in only 8 minutes.

What is the chemical composition of the Sun?
The Borexino results also provide an interesting clue to a previously unresolved solar mystery: What is the concentration of nuclei heavier than hydrogen and helium, the so-called metallicity? The higher the concentration of heavy nuclei, the more light is absorbed. This influences the temperature, size, brightness and life of the Sun.

To date, the Sun was assumed to have low metallicity. "Our results now indicate a solar temperature profile that suggests high metallicity," summarizes Prof. Lothar Oberauer of TUM and one of the founding members of the Borexino experiment.

Research Report: "Comprehensive measurement of pp-chain solar neutrinos"

Related Links
Technical University of Munich (TUM)
Stellar Chemistry, The Universe And All Within It

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

CREDO's first light: The global particle detector begins its collection of scientific data
Warsaw, Poland (SPX) Oct 05, 2018
Now everyone can become co-creator and co-user of the largest detector of cosmic ray particles in history - as well as a potential co-discoverer. All you need is a smartphone and the CREDO Detector application turned on overnight. Under development for over two years, the CREDO project is entering the era of its maturity. This week, at the Institute of Nuclear Physics of the Polish Academy of Sciences in Cracow, the "first light" of the detector was presented, that is, the first data of scientific value ... read more