Low energy neutrino astrophysics with the large liquid-scintillator detector LENA

The large-volume liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) will cover a broad field of physics. Apart from the detection of terrestrial and artificial neutrinos, and the search for proton decay, important contributions can be made to the astrophysics of stars by high-precision spectroscopy of low-energetic solar neutrinos and by the observation of neutrinos emitted by a galactic supernova. Moreover, the detection of the diffuse supernova neutrino background in LENA will offer the opportunity of studying both supernova core-collapse models and the supernova rate on cosmological timescales (z < 2). Significant constraints can be derived after ten years of exposure, resulting in ∼ 100 V_e events in an almost backgroundfree energy window from ∼ 10 to 25MeV. The search for such rare low-energetic events takes advantage of the high energy resolution and excellent background rejection possible in the LENA detector.