Recent Borexino results and perspectives of the SOX measurement

¹ Institute of Physics and Excellence Cluster PRISMA, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
² Gran Sasso Science Institute (INFN), 67100 L'Aquila, Italy
³ Physik-Department and Excellence Cluster Universe, Technische Universität München, 85748 Garching, Germany
⁴ National Research Centre Kurchatov Institute, 123182 Moscow, Russia
⁵ IKP-2 Forschungzentrum Jülich, 52428 Jülich, Germany
⁶ RWTH Aachen University, 52062 Aachen, Germany
⁷ Dipartimento di Fisica, Università degli Studi e INFN, 20133 Milano, Italy
⁸ Chemical Engineering Department, Princeton University, Princeton, NJ 08544, USA
⁹ Institut für Experimentalphysik, Universität Hamburg, 22761 Hamburg, Germany
¹⁰ INFN Laboratori Nazionali del Gran Sasso, 67010 Assergi (AQ), Italy
¹¹ Physics Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
¹² Physics Department, Princeton University, Princeton, NJ 08544, USA
¹³ Dipartimento di Fisica, Università degli Studi e INFN, 16146 Genova, Italy
¹⁴ Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, 119234 Moscow, Russia
¹⁵ Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822, USA
¹⁶ Commisariat à l'Énergie Atomique et aux Énergies Alternatives, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette, France
¹⁷ St. Petersburg Nuclear Physics Institute NRC Kurchatov Institute, 188350 Gatchina, Russia
¹⁸ Joint Institute for Nuclear Research, 141980 Dubna, Russia
¹⁹ AstroParticule et Cosmologie, Université Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, 75205 Paris Cedex 13, France
²⁰ Kepler Center for Astro and Particle Physics, Universität Tübingen, 72076 Tübingen, Germany
²¹ Department of Physics, University of Houston, Houston, TX 77204, USA
²² Laboratorio Subterráneo de Canfranc, Paseo de los Ayerbe S/N, 22880 Canfranc Estacion Huesca, Spain
²³ Commisariat à l'Énergie Atomique et aux Énergies Alternatives, Centre de Saclay, DEN/DM2S/SEMT/BCCR, 91191 Gif-sur-Yvette, France
²⁴ M. Smoluchowski Institute of Physics, Jagiellonian University, 30059 Krakow, Poland
²⁵ Kiev Institute for Nuclear Research, 03680 Kiev, Ukraine
²⁶ National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409 Moscow, Russia
²⁷ Physics Department, University of California, San Diego, CA 92093, USA
²⁸ Department of Physics, Technische Universität Dresden, 01062 Dresden, Germany
²⁹ Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi e INFN, 06123 Perugia, Italy
³⁰ Amherst Center for Fundamental Interactions and Physics Department, University of Massachusetts, Amherst, MA 01003, USA
³¹ Physics and Astronomy Department, University of California Los Angeles (UCLA), Los Angeles, California 90095, USA

^a e-mail: aporcell@uni-mainz.de

Published online: 3 August 2018

Abstract

Borexino is a liquid scintillator detector sited underground in the Laboratori Nazionali del Gran Sasso (Italy). Its physics program, until the end of this year, is focussed on the study of solar neutrinos, in particular from the Beryllium, pp, pep and CNO fusion reactions. Knowing the reaction chains in the sun provides insights towards physics disciplines such as astrophysics (star physics, star formation, etc.), astroparticle and particle physics. Phase II started in 2011 and its aim is to improve the phase I results, in particular the measurements of the neutrino fluxes from the pep and CNO processes. By the end of this year, data taking from the sun will be over and a new project is scheduled to launch: Short distance Oscillation with boreXino (SOX), which uses a Cerium source for neutrinos (100÷150 kCi of activity) and aims to confirm or rule out the presence of sterile neutrinos. This particle is hypothesised to justify the reactor, Gallium and LSND anomalies found and can reject extensions to the standard model. The work presented is a summary of the solar neutrino results achieved so far, which lead not only to a precise study of the processes in the sun, but also to more Standard Model oriented measurements (such as the stability of the charge, i.e. the life time of the electron). Furthermore, the perspectives of the SOX program are discussed showing the experiment sensitivity to a fourth neutrino state covering almost entirely 3σ of the preferred region of the anomalous neutrino experiments, and additional applications of the detector such as the study of geo-neutrinos.