Springer essentials Springer essentials provide up-to-date knowledge in a concentrated form. They aim to deliver the essence of what counts as "state-of-the-art" in the cur- rent academic discussion or in practice. With their quick, uncomplicated and comprehensible information, essentials provide:

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More information about this subseries at http://www.springer.com/series/16761 Claus Grupen

Neutrinos, Dark Matter and Co. From the Discovery of Cosmic Radiation to the Latest Results in Astroparticle Claus Grupen Department Physik Universität Siegen Siegen, Germany

ISSN 2197-6708 ISSN 2197-6716 (electronic) essentials ISSN 2731-3107 ISSN 2731-3115 (electronic) Springer essentials ISBN 978-3-658-32547-3 (eBook) https://doi.org/10.1007/978-3-658-32547-3

© Springer Fachmedien Wiesbaden GmbH, part of Springer Nature 2021 The translation was done with the help of artificial intelligence (machine translation by the service DeepL.com). A subsequent human revision was done primarily in terms of content. This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Responsible Editor: Margit Maly This Springer imprint is published by the registered company Springer Fachmedien Wiesbaden GmbH part of Springer Nature. The registered company address is: Abraham-Lincoln-Str. 46, 65189 Wiesbaden, Germany What You Can Find in This essential

The birth of astroparticle physics is the historic balloon flight of Victor Hess in 1912, when he discovered cosmic radiation with an ionization chamber. This cos- mic radiation was studied in many facets on the ground, under the earth, and in the atmosphere. It was soon discovered that cosmic rays were one way of stu- dying elementary particle processes. In order to understand the whole variety of phenomena in cosmic rays, one had to include many subareas of physics: Ther- modynamics, , physics, stellar physics, , and elementary particle processes, to name a few. Astroparticle physics is therefore multidisciplinary in every respect. Today, astroparticle physics is an active, inter- disciplinary field of research that includes and combines astronomy, cosmic rays, and elementary . In this essential, you will find a short historical outline of astroparticle physics and a description of the latest results without going into mathematical detail. This essential should be seen as an introduction to this new field of research. But you will get an overview of what is happening in the sky, between the stars and between the galaxies. By now, many things are quite well understood, but with every solution found, new questions arise. This range of questions with some answers can be found in this essential. A very detailed description of astroparticle physics, including a mathematical description of the relationships, especially in , can be found in the book “Entry into astro- particle physics” (“Einstieg in die Astroteilchenphysik”) by C. Grupen, published by Springer in 2018.

v vi What You Can Find in This essential

Muon showers in the ALEPH experiment 125 m below ground. (Picture credits: ALEPH experiment, https://home.cern/about/experiments/aleph, accessed on September 12, 2018. ALEPH experiment goes cosmic, https://cerncourier.com/1999/09/26/ and https://cernco urier.com/aleph-experiments-go-cosmic/, accessed on September 12, 2018. Avati, V. et al. (2003) Astropart. Phys. 19, pp. 513–523, Cosmic multi-muon events observed in the under- ground CERN-LEP tunnel with the ALEPH experiment; ALEPH experiment goes cosmic, https://www.hep.physik.uni-siegen.de/~grupen/, accessed on September 1, 2018) Preface

Whatever the final laws of nature may be, there is no reason to suppose that they are designed to make physicists happy (Steven Weinberg).

Cosmic rays have been falling on the Earth since the formation of the planets. The observation of auroras by Gassendi in 1621 and Halley in 1716 as aurora borealis (“northern dawn”) led Mairan to suspect in 1733 that this phenomenon was of extraterrestrial origin. The auroras are produced by electrons coming from the and entering the polar regions along magnetic field lines on helical orbits. Kant correctly assumed in 1775 that the “nebulae” observed in the sky were to be interpreted as an accumulation of individual stars into galaxies. At the beginning of the twentieth century, measurements of the recently dis- covered radioactivity led to the assumption that not all phenomena of ionizing radiation were of terrestrial origin. The proof of radiation from space was pro- vided by Victor Hess in his historic balloon flight to altitudes of over 5000 m. The “cosmic radiation” discovered in this way turned out to be a treasure trove of elementary particles to be newly discovered: antiparticles (positrons), muons, pions, and kaons were found in cosmic radiation experiments. With the advent of accelerators and storage rings, the particle zoo was greatly expanded until the quark model created an overdue order. The study of high-energy and rare processes led to a renaissance of cosmic rays—now renamed astroparticle physics. The measurement of solar neutrinos and neutrino oscillations, the discovery of gravitational waves and the simulta- neous measurement of cosmic catastrophes caused by electromagnetic radiation, particle radiation and gravitational waves (“multi-messenger astronomy”) provi- ded new insights into the universe. Nevertheless, there are still many unanswered questions: Where is dark matter hiding? Is a property of space? Do

vii viii Preface we live in a higher-dimensional space? And finally: Is our universe embedded in a multiverse?

Siegen October 2018 Acknowledgment

I would like to thank Dr. Tilo Stroh for a careful review of the manuscript and especially for his prompt and effective support in solving problems that may arise, which he was always able to solve professionally and quickly.

ix Contents

1 Historical Introduction to Astroparticle Physics ...... 1 1.1 Introduction ...... 1 1.2 TheLastCentury ...... 2 1.3 Contributions of Elementary Particle Physics ...... 7 1.4 Renaissance of Astroparticle Physics and Open Questions ...... 9 2 Charged Component of Primary Cosmic Radiation ...... 11 3 X-ray Astronomy ...... 17 4 Gamma Astronomy ...... 21 5NeutrinoAstronomy...... 25 5.1 SolarNeutrinos ...... 26 5.2 SupernovaNeutrinos ...... 28 5.3 High-EnergyNeutrinos ...... 29 6 Gravitational Waves ...... 35 7 Cosmology ...... 39 8 ...... 45 9 Outlook ...... 47

Literature ...... 51