DOCSLIB.ORG

Neutrino Simulation 14 3.1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Neutrino Simulation 14 3.1 Analysis of neutrino event generators for KM3NeT/ORCA Bachelorarbeit vorgelegt von Patrick Heuer Erlangen Centre for Astroparticle Physics Physikalisches Institut 4 Friedrich-Alexander-Universität Erlangen-Nürnberg 1. Gutachter: Dr. Thomas Eberl 2. Gutachter: Prof. Dr. Gisela Anton Tag der Abgabe: 09. 07. 2018 Contents 1. Introduction 3 2. Neutrino detection5 2.1. Neutrino physics . .5 2.1.1. Elementary particles and fundamental forces . .5 2.1.2. Neutrino oscillation . .6 2.1.3. Neutrino-nucleus interactions . .7 2.1.4. Cross-sections . .9 2.2. Detection principles . 10 2.2.1. Cherenkov light . 11 2.2.2. Neutrino telescopes . 11 2.2.3. KM3NeT/ORCA . 12 3. Neutrino simulation 14 3.1. gSeaGen . 14 3.2. GiBUU . 15 3.2.1. Job card . 15 3.2.2. Output file . 16 3.2.3. Cross-sections . 17 3.3. Comparison . 17 3.3.1. yb-distributions . 19 3.3.2. yb-φν,µ distributions . 20 3.3.3. Mean yb ....................................... 22 3.3.4. Scatter type ratio . 23 3.3.5. Particle multiplicities . 26 3.3.6. Mean particle production . 26 3.3.7. Mean pion production . 26 3.4. Differences in GiBUU by changing the use of PYTHIA . 28 3.4.1. Cross-sections . 29 3.4.2. yb-distributions . 30 3.4.3. Mean yb ....................................... 30 1 2 Contents 3.4.4. Scatter type ratio . 32 3.4.5. Particle-production . 32 4. Summary and conclusion 34 List of Figures 36 List of Tables 39 Bibliography 40 A. example job card 43 B. yb distributions 45 C. yb-φν,µ distributions 53 D. Particle production 55 E. New PYTHIA settings 59 1 Introduction The detection of neutrinos is a challenge in experimental physics dating back to 1930, when Wolfgang Pauli postulated them. From there, it took over 20 years to finally prove the existence of the elusive particle in the Cowan?Reines neutrino experiment.[1] To learn about the properties of the neutrino, one has to detect the particles produced in interactions with matter. Once believed to be massless in the Standard Model of particle physics, we know today that neutrinos have a rest mass. This results in an effect called neutrino oscillation, where a neutrino changes its flavour during propagation. This is firmly established by a number of experiments measuring the corresponding squared mass differences and mixing angles occurring in the theory of neutrino oscillation.[2–7] One of the remaining questions is the hierarchy of the mass eigenstates or more 2 precisely the sign of the larger of the two mass-squared differences ∆m23. One approach to learn about the phenomenon of neutrino oscillations, is the detection of neutrinos created in air-showers, induced by cosmic rays in the atmosphere, after propagating through the Earth. This approach is pursued by KM3NeT/ORCA, a future multi-megaton underwater Cherenkov detector.[8, 9] To understand the measurements of ORCA and generally all neutrino telescopes, we rely on the use of simulations of the interaction of neutrinos, in the detector material. In the first step in such simulations, a so-called event generator is employed, simulating the first interaction and the final state particles of the reaction. Over the last decade it has become evident that the standard approach used in neutrino simulations, namely the Relativistic Fermi Gas Model (RFGM), conspicuously fails to account for the complexity of nuclear dynamics and the variety of reaction mechanisms contributing to the detected signals.[10] The currently used event generator in the KM3NeT collaboration is gSeaGen, a home-brew generator based on GENIE, which relies on the RFGM. An improvement of these simulations could be achieved using the new generator GiBUU. GiBUU was written over the last decades and is aiming to provide a unified theoretical transport framework in the MeV and GeV energy regimes for a wide array of reaction types like hadron-, photon-, electron-, neutrino- and heavy-ion-induced reactions on nuclei.[11] The goal of this thesis is to understand the usage of GiBUU for KM3NeT/ORCA and compare its output to the one of gSeaGen. To do this it will first introduce the physical principles involved in neutrino detection, following with an introduction of the two generators and a comparison of the 3 4 1. Introduction respective output. It will end with an evaluation, summarizing the found contradictions between the generators and search for explanations of these. 2 Neutrino detection Neutrinos are electrically neutral, extremely light particles with spin 1/2 that only have weak and gravitational interaction. They were postulated in 1930 by Wolfgang Pauli as a remedy to conserve energy in the beta decay. First assumed to be massless, neutrinos have the ability to change their flavour, in a process called neutrino oscillation. This behaviour can only be explained if neutrinos have mass. To better understand this phenomenon and to determine the mass hierarchy of neutrino masses, neutrino telescopes, like the future KM3NeT/ORCA, measure atmospheric neutrinos in the few-GeV range. 2.1. Neutrino physics Covering all physical principles involved in neutrino physics is beyond the scope of this thesis. A short summary of relevant principles will be given with a focus on those most relevant for the thesis. 2.1.1. Elementary particles and fundamental forces Elementary particles are particles that have no known constituents. These particles and their fundamental interactions are explained in the Standard Model of particle physics. The current elementary particles are grouped into three classes: quarks, leptons and gauge bosons. There are six known quarks: up, down, charm, strange, top and bottom. They are the only particles to carry a fractional electric charge and are the constituents of hadrons, held together by the strong force. These are grouped into baryons (three quarks) and mesons (two quarks). The most commonly known baryons are protons, consisting of two up and one down-quark and neutrons, consisting of two down and one up-quark. Mesons are unstable products of particle interactions involving quarks. The lightest meson is the pion (π) consisting of a quark-anti-quark pair. Leptons can be categorized into two groups, electrically charged (with a charge of -1e, where e is the elementary charge) and electrical-neutral leptons. The best-known charged lepton is the electron (e−), whereas muons (µ−) and taus (τ −) can be described as heavier versions of the e−. Every charged lepton has a corresponding neutral lepton, the neutrino (νe, νµ, ντ ). The correspondence of the 5 6 2. Neutrino detection Family Name Charge (e) Interaction Quark up 3/2 em, strong, weak, gravitation down -1/2 em, strong, weak, gravitation charm 3/2 em, strong, weak, gravitation strange -1/2 em, strong, weak, gravitation top 3/2 em, strong, weak, gravitation bottom -1/2 em, strong, weak, gravitation Lepton e− 1 em, weak, gravitation νe 0 weak, gravitation µ− 1 em, weak, gravitation νµ 0 weak, gravitation τ − 1 em, weak, gravitation ντ 0 weak, gravitation Family Name Charge (e) Force carrier of Gauge boson γ 0 em gluon 0 strong W ± ±1 weak Z0 0 weak Table 2.1.: Elementary particles and the force carriers of the fundamental forces. neutrino to one of the charged lepton is called flavour. Each of these particles interact only via certain fundamental forces. There are four known fundamental forces: the electromagnetic (em) force, the strong force, the weak force and the gravitational force. While the electromagnetic and the gravitational force act on infinite scales the strong and the weak force only act on subatomic levels. All these forces interact via the exchange of gauge bosons. Every force is mediated via another one of these bosons. The boson mediating the electromagnetic force is the photon (γ), the ones mediating the weak force are the Z0, W + and W −, the ones mediating the strong force are gluons and the one mediating the gravitational force, called graviton, is, to this day, still hypothetical. An overview of the different particles, their charge and their interactions can be found in Table 2.1. Every particle has one corresponding anti-particle with same mass but opposite charge. For example, the anti-particle of the e− is the positron e+, with same mass but a positive charge. For further reading about the Standard Model of particle physics see [12] and [13]. 2.1.2. Neutrino oscillation In the last decade a number of experiments were conducted that showed neutrinos change their flavour over time. This can be explained with neutrino oscillations, resulting from the flavour eigenstates (νe, νµ and ντ ) being linear combinations of the mass eigenstates (ν1, ν2 and ν3). If we only consider the 2.1. Neutrino physics 7 eigenstates νµ, ντ , ν2 and ν3 the linear combinations would be νµ = ν2 cos θ23 + ν3 sin θ23 ντ = −ν2 sin θ23 + ν3 cos θ23 with θ23 the so-called mixing angle. If the eigenstates are evolved in time, one can show the probability of a νµ staying in its flavour is 2 ! 2 2 1.27∆m23L P (νµ → νµ) = 1 − sin (2θ23) sin , Eν 2 2 2 with m23 = m3 − m2 the difference in the squared masses, L the distance the neutrino travelled and Eν the energy of the neutrino.[14] In the 3-ν framework the mixing between the states is given in the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix U: −iδ 1 0 0 c13 0 e s13 c12 s12 0 U = 0 c23 s23 × 0 1 0 × −s12 c12 0 iδ 0 −s23 c23 −e s13 0 c13 0 0 1 with δ, the complex CP phase, cij = cos θij and sij = sin θij. Contradictory to the Standard Model of particle physics, the existence of neutrino oscillations imply a non-zeo neutrino rest mass.
Load more

Recommended publications
  • First International Four Seas Conference
    CERN 97-06 31 July 1997 XC98FK266 ORGANISATION EUROPEENNE POUR LA RECHERCHE NUCLEAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH FIRST INTERNATIONAL FOUR SEAS CONFERENCE Trieste, Italy 26 June-1 July 1995 PROCEEDINGS Editors: A.K. Gougas, Y. Lemoigne, M. Pepe-Altarelli, P. Petroff, C.E. Wulz GENEVA 1997 CERN-Service d'information scientifique-RD/975-200O-juiUet 1997 d) Copyright CKRN, Genève. IW7 Propriété littéraire et si'icnlirii|iic réservée Literary and scientific copyrights reserved in all pour tous les pays du monde. Ce document ne countries of the world. This report, or any part peut être reproduit ou traduit en tout ou en of it, may not be reprinted or translated partie sans l'autorisation écrite du Directeur without written permission of the copyright général du CHRN. titulaire du droit d'auteur. holder, the l)irector-(ieneral of CHRN. Dans les cas appropriés, et s'il s'agit d'utiliser However, permission will he freely granted for le document à des lins non commerciales, cette appropriate noncommercial use. autorisation sera volontiers accordée. II any patentable invention or registrable design l.c CHRN ne revendique pas la propriété des is described in the report, (T!RN makes no inventions hrevclablcs et dessins ou modèles claim to properly rights in it but offers it for the susceptibles de dépôt qui pourraient être free use of research institutions, manu- décrits dans le présent document; ceux-ci peu- facturers and others. CHRN, however, may vent être librement utilisés par les instituts de oppose any attempt by a user to claim any recherche, les industriels et autres intéressés.
    [Show full text]
  • Detection of Geoneutrinos: Can We Make the Gnus Work For
    Detection of Geoneutrinos: Can We Make the Gnus Work for Us? John G. Learned Department of Physics and Astronomy, University of Hawaii, 2505 Correa Road, Honolulu, HI 96822 USA The detection of electron anti-neutrinos from natural radioactivity in the earth has been a goal of neutrino researchers for about half a century[21, 22, 23, 24, 25, 26]. It was accomplished by the KamLAND Collaboration in 2005[27], and opens the way towards studies of the Earth’s radioactive content, with very important implications for geology. New detectors are operating (KamLAND[3] and Borexino[2]), building (SNO+[4]) and being proposed (Hanohano, LENA, Earth and others) that will go beyond the initial observation and allow interesting geophysical and geochemical re- search, in a means not otherwise possible. Herein we describe the approaches being taken (large liquid scintillation instruments), the experimental and technical challenges (optical detectors, direc- tionality), and prospects for growth of this field. There is related spinoff in particle physics (neutrino oscillations and hierarchy determination), astrophysics (solar neutrinos, supernovae, exotica), and in the practical matter of remote monitoring of nuclear reactors. PACS numbers: I. INTRODUCTION: GEONEUTRINO STUDIES tivity required demands employment of expensive liquid STARTED scintillators in order to produce significant light (yielding 30-50 times that from a Cherenkov detector) and further, The preceding paper, “Why Geoneutrinos are almost all neutrino directionality is lost. Further, delicate Interesting”[1], really sets the stage for this contribu- care must be taken for radiopurity, now well understood tion to NU2008. McDonough explains that the flux of but not easy. geoneutrinos coming mainly from the natural radioactive The process employed for detection of the anti- decay chains of Uranium and Thorium from throughout neutrinos is the inverse beta decay, used by researchers the earth, serves as a tag for the abundance and loca- since the initial observations of these neutrinos by Cowan tion of these rare isotopes.
    [Show full text]
  • History of High-Energy Neutrino Astronomy
    History of high-energy neutrino astronomy C. Spiering DESY, Platanenallee 6, D-15738 Zeuthen, Germany This talk sketches the main milestones of the path towards cubic kilometer neutrino telescopes. It starts with the first conceptual ideas in the late 1950s and describes the emergence of concepts for detectors with a realistic discovery potential in the 1970s and 1980s. After the pioneering project DUMAND close to Hawaii was terminated in 1995, the further development was carried by NT200 in Lake Baikal, AMANDA at the South Pole and ANTARES in the Mediterranean Sea. In 2013, more than half a century after the first concepts, IceCube has discovered extraterrestrial high-energy neutrinos and opened a new observational window to the cosmos { marking a milestone along a journey which is far from being finished. 1 From first concepts to the detection of atmospheric neutrinos The initial idea of neutrino astronomy beyond the solar system rested on two arguments: The first was the expectation that a supernova stellar collapse in our galaxy would be accompanied by an enormous burst of neutrinos in the 5-10 MeV range. The second was the expectation that fast rotating pulsars must accelerate charged particles in their Tera-Gauss magnetic fields. Either in the source or on their way to Earth they must hit matter, generate pions and neutrinos as decay products of the pions. The first ideas to detect cosmic high energy neutrinos underground or underwater date back to the late fifties (see 1 for a detailed history of cosmic neutrino detectors). In the 1960 Annual Review of Nuclear Science, K.
    [Show full text]
  • Characterizing the Diffuse Neutrino Flux with the Future Km3net/ARCA
    Characterizing the diffuse neutrino flux with the future KM3NeT/ARCA detector Charakterisierung des diffusen Neutrinoflusses mit dem zukunftigen¨ KM3NeT/ARCA-Neutrinoteleskop Der Naturwissenschaftlichen Fakultat¨ der Friedrich-Alexander-Universitat¨ Erlangen-Nurnberg¨ zur Erlangung des Doktorgrades Dr. rer. nat. vorgelegt von Thomas Gerhard Georg Heid aus Roth Als Dissertation genehmigt von der Naturwissenschaftlichen Fakultat¨ der Friedrich-Alexander-Universitat¨ Erlangen-Nurnberg¨ Tag der mundlichen¨ Prufung:¨ 13.12.2018 Vorsitzender des Promotionsorgans: Prof. Dr. Georg Kreimer Gutachter: Prof. Dr. Gisela Anton Dr. Paschal Coyle Contents 1 Introduction 6 2 Neutrino physics8 2.1 Neutrino properties...................................8 2.2 Neutrino production...................................8 2.2.1 Neutrinos from astrophysical sources.....................9 2.2.2 Neutrinos produced in the Earth’s atmosphere................. 11 2.3 Neutrino Oscillation................................... 12 2.4 Neutrino interaction................................... 13 2.4.1 Interactions of neutrinos of all kinds of flavor in the neutral current..... 15 2.4.2 Interaction of νe in the charged current..................... 15 2.4.3 Interaction of νµ in the charged current..................... 15 2.4.4 Interactions of ντ in the charged current.................... 16 3 KM3NeT: A worker for neutrino astronomy 18 3.1 KM3NeT........................................ 18 3.2 Future prospects of neutrino astronomy........................ 20 4 Detector Simulation 21 5 Atmospheric
    [Show full text]
  • Improving Event Classification at Km3net with Orcanet
    Improving event classification at KM3NeT with OrcaNet A thesis submitted in fulfillment of the requirements for Master in Experimental Physics at Universiteit Utrecht Author Enrique Huesca Santiago July, 2019 2 Abstract Neutrino telescopes such as KM3NeT are being built to detect these tiny, elusive particles. In the case of KM3NeT ORCA the aim is to determine the currently unknown neutrino mass hierarchy, which has far reaching implications for scientific research. Distinguishing between the different types of neutrino flavour interactions seen in the detector is critical for this goal. In order to achieve this, Deep-Learning algorithms such as the OrcaNet framework for KM3NeT are being developed and tested. This work consists of an exploration of the performance of this tool for the concrete case of event identification in KM3NeT, and its implications for determining the neutrino mass hierarchy. Here, clear evidence is presented that there is potential for event classification and identification beyond the current binary track-shower scheme, including up to 40% separation for electron neutrino charged current events. Para mamá y papá, los mejores científicos que nunca han sido. Student number: 6310141 Thesis Research Project: 60 ECTS Contact: [email protected] Supervisor: Paul de Jong First Examiner: Raimond Snellings Second Examiner: Alessandro Grelli Word Count: 24966 3 Contents 1 Introduction6 1.1 Motivation.................................6 1.2 Neutrino classification.......................... 10 1.3 Cherenkov Radiation........................... 11 2 Neutrino Physics 12 2.1 Neutrino Discovery............................ 12 2.2 Neutrino Oscillations........................... 14 2.2.1 Neutrino Mixing Formalism................... 14 2.2.2 The Solar Neutrino Problem................... 16 2.2.3 3 flavour neutrino oscillations.................
    [Show full text]
  • Origin and Propagation of Extremely High Energy Cosmic Rays
    To appear in Physics Reports E-Print astro-ph/9811011 Origin and Propagation of Extremely High Energy Cosmic Rays Pijushpani Bhattacharjee1 Indian Institute of Astrophysics, Bangalore-560 034, India. G¨unter Sigl2 Astronomy & Astrophysics Center, Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA Abstract Cosmic ray particles with energies in excess of 1020 eV have been detected. The sources as well as the physical mechanism(s) responsible for endowing cosmic ray particles with such enormous energies are unknown. This report gives a review of the physics and astrophysics associated with the questions of origin and propagation of these Extremely High Energy (EHE) cosmic rays in the Universe. After a brief review of the observed cosmic rays in general and their possible sources and acceleration mechanisms, a detailed discussion is given of possible “top-down” (non-acceleration) scenarios of origin of EHE cosmic rays through decay of sufficiently massive particles originating from processes in the early Universe. The massive particles can come from collapse and/or annihilation of cosmic topological defects (such as monopoles, cosmic strings, etc.) associated with Grand Unified Theories or they could be some long- lived metastable supermassive relic particles that were created in the early Universe and are decaying in the current epoch. The highest energy end of the cosmic ray spectrum can thus be used as a probe of new fundamental physics beyond Standard Model. We discuss the role of existing and proposed cosmic ray, gamma-ray and neutrino experiments in this context. We also discuss how observations with next generation experiments of images and spectra of EHE cosmic ray sources can be used to obtain new information on Galactic and extragalactic magnetic fields and possibly their origin.
    [Show full text]
  • An Overview of the Experimental High Energy Activities in Greece Chara
    An overview of the Experimental High Energy Activities in Greece Chara Petridou, Aristotle University of Thessaloniki, Greece [email protected] The Activities An overview of the Experimental High Energy Activities in Greece Greek Experimental HEP Activities Chara Petridou Aristotle University of Thessaloniki Accelarator Non-Accelerator Detector/Acceleratotor Experiments Experiments R&D PhD's 44 PhD's 12 PhD's 3 PhD-students 30 PhD-students 4 PhD-students 2 Accelerator Physics Experiments Accelerator Physics Activities CERN Fermilab Experiments DESY Experiments LHC Exper imen ts nTOF Tevatron-CDF Neutrino Physics HERA-H1/ZEUS PhD's 1 ATLAS CMS ALICE PhD's 1 PhD's 3 PhD-students 2 PhD's 18 PhD's 17 PhD's 3 PhD-students 1 PhD-students 1 PhD-students 10 PhD-students 10 PhD-students 5 Non-Accelerator Physics The Greek ATLAS Project Experiments NKUoA, NTUA, AUTh all three institutes collaborated for the construction of the BIS chambers of the ATLAS Muon sSpectrometer, consisting of 128 MTD Muon chambers Experiments in Greece Experiments at CERN All chambers installed in the ATLAS pit since Dec 2006 NESTOR HELYCON CAST PhD's 4 PhD's 3 PhD's 4 PhD-students 2 PhD-students 2 All chambers commissioned with cosmic rays Ready for data taking C. Kourkoumelis This Conference 3 Demokritos University National Center for University The Greek ATLAS Project CMS in Greece of Athens Scientific Research of Ioannina Preshower • Muon studies: 2008: 17 PhD physicists Participation: Endcap • CMS Preshower (DEMOKRITOS-UoI) ECAL DCS and HV/LV, Bfield control
    [Show full text]
  • A Neutrino Universe
    Quick Review of HE Neutrino Detectors Neutrino Physics is Blossoming, Neutrino Telescopes are Coming into Reality and New Techniques are Pioneered. We are about to begin regular neutrino astronomy! John Learned at ASHRA Meeting in Hawaii, 8 January 2004 ν Outline Projects, old and new: Underground (SK, Soudan, INO, HyperK, UNO….) Underwater and Ice (ANTARES, AMANDA, Baikal, Icecube, NEMO,NESTOR) Radio from the Moon and Earth (GLUE, RICE, ANITA, SALSA) Hearing Neutrinos (AUTEC, SADCO) GZK EAS Projects are ν detectors too (AGASA, HiRes, AUGER, EUSO, OWL, ASHRA) And this in not even mentioning the explosion in neutrino experiments at or associated with accelerators (K2K, Minos, MiniBOONE, ICARUS, JHF …) and at lower energies (KamLAND, SNO, GNO, Gallex,….) For review see J. Learned and K. Mannheim, Ann. Rev. Nucl. Part. Sci. 2000, 50:679-749 2 8 January 2004 John Learned at ASHRA mtg Super-Kamiokande ν BiggestBiggest CurrentCurrent UndergroundUnderground νν DetectorDetector rebuiltrebuilt inin 20022002 toto ½½ densitydensity ofof PMTsPMTs Since Apr. ’96, >1400 days 22,500 ton fiducial Vol. 1,200 m2 muon area 4 MeV – 200 GeV evts ~20,000 Solar ν’s >11,000 FC atm ν’s >2000 upcoming µ’s Strong evidence for νµ↔ντ oscillations ▫ also from K2K, Soudan & MACRO ICRR, U-Tokyo 3 8 January 2004 John Learned at ASHRA mtg SuperK Upcoming Muon Cosmic ν Limits ν EEμ>1.4>1.4 GeV;GeV; <E<Eν>~100>~100 GeVGeV ButBut SadlySadly nono SignalsSignals YetYet Preliminary others from CWRU, KGF, Baksan, Frejus, IMB, Kam, Baikal, MACRO, AMANDA…. Matsuno, UH 4 8 January 2004 John Learned at ASHRA mtg ButBut NeutrinoNeutrino AstronomyAstronomy BeganBegan withwith ν Solar Neutrinos 30 Yrs Ago! • SK Portrait of the Sun in Neutrinos • Data from Homestake, SAGE, GALLEX/GNO, Kamioka, SuperK, SNO • But Flux Only ~1/2-1/3 of Expectations R.
    [Show full text]
  • Periodic Table of the Elements
    Appendix A Periodic Table of the Elements Source From K.A. Olive et al. (Particle Data Group), Chin. Phys. C 38 (2014) 090001 © Springer-Verlag Italia 2015 647 A. De Angelis and M.J.M. Pimenta, Introduction to Particle and Astroparticle Physics, Undergraduate Lecture Notes in Physics, DOI 10.1007/978-88-470-2688-9 Appendix B Properties of Materials Source From K.A. Olive et al. (Particle Data Group), Chin. Phys. C 38 (2014) 090001 © Springer-Verlag Italia 2015 649 A. De Angelis and M.J.M. Pimenta, Introduction to Particle and Astroparticle Physics, Undergraduate Lecture Notes in Physics, DOI 10.1007/978-88-470-2688-9 Appendix C Physical and Astrophysical Constants Source From K.A. Olive et al. (Particle Data Group), Chin. Phys. C 38 (2014) 090001 © Springer-Verlag Italia 2015 651 A. De Angelis and M.J.M. Pimenta, Introduction to Particle and Astroparticle Physics, Undergraduate Lecture Notes in Physics, DOI 10.1007/978-88-470-2688-9 652 Appendix C: Physical and Astrophysical Constants Index Symbols ATLAS experiment, 152 0 K 0 − K Mixing, 310 Aurorae, 624 CDM model, 468, 477, 486 Avalanche photodiodes (APD), 131 αi matrices, 260 Axion, 385, 491 β matrix, 260 Axion-like-particle (ALP), 491, 610 τ-θ puzzle, 95 γ μ matrices, 260 B Baikal NT-200 detector, 181 A Barn, 28 Abelian symmetry groups, 324 Baryon Acoustic Oscillations, 428, 485 Accelerators, 189 Baryons, 190, 214 ACE experiment, 157 baryonic quantum number, 191 Acoustic peaks, 437 Beauty, see Bottom Active galactic nuclei (AGN), 576 BESS experiment, 157 AGASA experiment, 159 β decay,
    [Show full text]
  • The Saga of Atmospheric Neutrinos
    The Saga of Atmospheric Neutrinos John Gregory Learned University of Hawaii A Saga? Yes, a great scientific tale of persistence, dead ends, serendipitous discovery, re- demption and glory. Dictionary definition of a Saga: \a long story of heroic achievement, especially a medieval prose narrative in Old Norse or Old Icelandic." (OED). Indeed the tale of atmospheric neutrino studies has much of this. 1 Neutrino Sources From whence do neutrinos originate? The dominant sources we know are: • Nuclear Reactors (power stations, ships, test reactors), known and observed since the 1950's. • Particle Accelerators make them from collisions of beams of protons into targets and subsequent mesons decaying to muons and those allowed to decay in flight, as at Fermilab, CERN, KEK and Tokai. • Atmospheric Neutrinos from GeV to TeV energies, produced by incoming cosmic rays colliding with air nuclei in the high atmosphere and then the secondary pions and kaons decaying in flight through the atmosphere. • Geo-neutrinos from throughout Earth's mass from primordial Uranium, Thorium and Potassium decay chains, long predicted but hard to detect, and first observed in 2005. • The Sun and indeed all stars produce vast numbers of electron neutrinos, bathing the Earth day and night. The flux of solar neutrinos at earth totally overwhelms the summed flux from all the rest of the Universe. • Supernova (SN) neutrinos are the exception where a huge bursts may be seen from SN not much further away than out neighbor galaxies (SN1987A), with detectors in the class of < 100 kT. Attempts have been made to see the sum of all SN neutrinos, but that flux has been beyond reach as yet (maybe in a few years in Hyper-Kamiokande).
    [Show full text]
  • For Many Years, Physicists Searching for and Studying Delicate Physics Effects Have Been Working in the Shelter of Large Underground Installations
    ^EEF^ANEOTmN^ElESCOPES^^^ Between neutrinos a For many years, physicists searching for and studying delicate physics effects have been working in the shelter of large underground installations. Now the ocean too is the scene of new physics developments. Where do cosmic rays come from? What mechanisms can acceler­ ate particles to ultrahigh energies? What happens around a super- massive black hole? What kind of phenomenon is responsible for the mysterious gamma-ray bursts? Have dark matter particles gath­ ered in the centre of the Earth or of the galaxy? These questions and many others now motivate ambitious experiments in high- energy astrophysics. Astronomy with high-energy neutrinos may soon be able to answer some of these questions and drastically change our point of view on the universe. If one wants to understand the sources of high-energy cosmic rays, one faces a fundamental difficulty: at high energy the tradi­ tional messenger, the photon, is absorbed by the radiation and mat­ ter that it encounters along its path from the sources to the detectors - the universe is actually opaque to high-energy gamma Immersion of a protoype module for the ANTARES underwater rays. Primary cosmic rays are electrically charged so they are neutrino observatory. deflected by galactic and intergalactic magnetic fields, and it is hard to identify their sources. To look at the high-energy sky, one is thus forced to use another messenger that is electrically neutral and basi­ cally insensitive to obstacles. The neutrino is the ideal messenger. Underwater observatories However, because of these essential qualities, neutrinos are also dif­ ficult to detect: one needs a big target to catch them - bigger than the already huge existing underground detectors.
    [Show full text]
  • Neutrino Telescopes in the Mediterranean Sea
    Neutrino Telescopes in the Mediterranean Sea Juan José Hernández-Rey1 IFIC – Instituto de Física Corpuscular, CSIC-Universitat de València, apdo. 22085, E-46017 Valencia, Spain [email protected] Abstract. The observation of high energy extraterrestrial neutrinos can be an invaluable source of information about the most energetic phenomena in the Universe. Neutrinos can shed light on the processes that accelerate charge particles in an incredibly wide range of energies both within and outside our Galaxy. They can also help to investigate the nature of the dark matter that pervades the Universe. The unique properties of the neutrino make it peerless as a cosmic messenger, enabling the study of dense and distant astrophysical objects at high energy. The experimental challenge, however, is enormous. Due to the weakly interacting nature of neutrinos and the expected low fluxes very large detectors are required. In this paper we briefly review the neutrino telescopes under the Mediterranean Sea that are operating or in progress. The first line of the ANTARES telescope started to take data in March 2006 and the full 12-line detector was completed in May 2008. By January 2009 more than one thousand neutrino events had been reconstructed. Some of the results of ANTARES will be reviewed. The NESTOR and NEMO projects have made a lot of progress to demonstrate the feasibility of their proposed technological solutions. Finally, the project of a km3-scale telescope, KM3NeT, is rapidly progressing: a conceptual design report was published in 2008 and a technical design report is expected to be delivered by the end of 2009.
    [Show full text]