Wuppertal 2015 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 53: Niederenergie Neutrinophysik III

T 53.6: Vortrag

Dienstag, 10. März 2015, 18:10–18:25, I.12.01 (HS 30)

First direct detection of solar pp neutrinos by Borexino — •Werner Maneschg on behalf of the Borexino collaboration — Max-Planck-Institut für Kernphysik, Heidelberg

According to the Standard Solar Model (SSM) the radiative energy of our Sun is produced by a series of nuclear reactions that convert hydrogen into helium. In 99% of cases these processes are supposed to start with a fusion of two protons and the emission of a positron and a low-energy neutrino. These so-called pp neutrinos vastly outnumber those emitted in other sub-reactions, but only the large volume organic liquid scintillator detector Borexino has recently succeeded to perform a spectroscopic and direct measurement of them.

The present talk reviews the procedure adopted by the Borexino collaboration to detect pp neutrinos. The key requirements, i.e. unprecedented radiopurity levels at low energies and a precise spectral description of the main background arising from 14C decays, and their fulfillment are discussed. The measured pp neutrino flux is then compared with the predictions of the SSM including neutrino oscillation mechanisms, and with the solar luminosity constraint deduced from photospheric observations.