Cafe Scientifique Neutrinos Thomas Gajdosik Neutrinos and their Oscillations · Historical Context Thomas Gajdosik · Todays Understanding Faculty of Physics · Meaning of Oscillations Department of Theoretical Physics Cafe Scientifique Neutrinos Thomas Gajdosik Historical Context discoveries in particle physics Cafe Scientifique Neutrinos Thomas Gajdosik Radioactivity u u While working on phosphorescent mate- u u rials Antoine-Henri Becquerel discovers u Radioactivity. He finds traces on photo- u graphic plates that were not exposed to u u light. u u u u u u u u Becquerel u u u Henri Becquerel: Photographic plate showing effects of radioactivity. " u u 1896 u {w I Cafe Scientifique Neutrinos Thomas Gajdosik . u e− the electron . u u u u u u u u J.J. Thomson u u u u u u u u u u u u u u 1897 u {{w I Cafe Scientifique Neutrinos Thomas Gajdosik . e− Transmutation of Chemical Elements . u . u u γ u. u u u u u u u Soddy Rutherford u u u 1901 Frederick Soddy and Ernest Rutherford discovered u that radioactive thorium was converting itself into radium. u u At the moment of realization, Soddy later recalled, he shouted out: "Rutherford, this u is transmutation!" Rutherford snapped back, "For Christ’s sake, Soddy, don’t call it u transmutation. They’ll have our heads off as alchemists." u u 1896 1901 u {{ {w I Cafe Scientifique Neutrinos Thomas Gajdosik . e− Continuous electron spectrum . in radioactive -decay u β . u u γ u. u u u u u u u u u u u 1911 Otto Hahn and Lise Meitner u u observe a continuous spectrum of u electrons coming from radioactive u Meitner Hahn u β-decay. u 1896 1911 u {{ { {w I Cafe Scientifique Neutrinos Thomas Gajdosik . e− Radioactive displacement law . of Fajans and Soddy u . u u γ u. u u u u u u u u Fajans Soddy u u u u 1913 Frederick Soddy and Kazimierz Fajans u formulate independently the radioactive u u displacement law. u u 1896 1913 u {{ { { {w I Cafe Scientifique Neutrinos Thomas Gajdosik . u ep− the proton – the atomic nucleus . u u . u u γ THOMSON fluorescentscreen u. u gold foil u u alpha particle beam u u radiation source (radium) u Rutherford u RUTHERFORD u u u u u u u Geiger Marsden u u u 1896 1914 u {{ { { {{w I Cafe Scientifique Neutrinos Thomas Gajdosik . ep− Stern-Gerlach experiment ! Spin . u . u u γ u. u u u u u Gerlach Stern u u u u u u u u u Uhlenbeck Goudsmit u u u 1897 1922 1925 u {{ { { {{ {w {w I Cafe Scientifique Neutrinos Thomas Gajdosik . u eνp− the neutrino – theory prediction . u u . u u γ u. u . u u . n . Pauli: u u ”neutron” Fermi: ”neutrino” µ− . u u . π . + u e u . u u u u u u u u 1897 1930 1956 u {{{ { { {{ { { {wI ws Cafe Scientifique Neutrinos Thomas Gajdosik Fermi Theory • 1933 Enrico Fermi explained the radioactive beta decay – by coupling charged currents • the same coupling constant . −5 1:16637×10 e− G = describes . F GeV2 – radioactive beta-decay . .. + . ν¯e µ – muon decay . µ− . + . π – charged pion decay . νµ . νµ – neutrino interactions . F but it cannot work for energies bigger than ∼100 GeV 1897 1933 {{{ { { {{ { { { {w I Cafe Scientifique Neutrinos Thomas Gajdosik . u ep− the neutron . u u . u u γ u. u . u u n u. u u Chadwick u u . u u . u u u u u u u 1897 1932 u {{{{ {{{ {{ {{{w I Cafe Scientifique Neutrinos Thomas Gajdosik . u ep− the muon . u u Raby: ”Who ordered that one?” . u u γ u. u Cosmic . Rays u u (10km) . n u. Hess Anderson µ− u . u u u u u u u u u Spark Chamber u u u 1897 1936 u {{{{ {{{ {{ {{{{w I Cafe Scientifique Neutrinos Thomas Gajdosik . ep− Nuclear fusion cycle in the sun . u . u pp-chain u γ .u u 1H 1H 1H 1H . CNO-cycle u u n ν ν . 4 u He 1 H u 1H 2H 1H 1H 2H Weizsäcker u 12C u 15 N 13N γ γ u u 3He 3He 15 O 13C u 14 u N u 1H 1H 1H u 1H Proton Proton Gamma Ray u γ Gamma Ray 4 Neutron Neutron Neutrino u ν Neutrino He Positron Positron Bethe u u 1897 1937-1939 u {{{ { { {{ { { { {{ {{{{w w w I Cafe Scientifique Neutrinos Thomas Gajdosik . u eνp¯− antineutrino . u u Cowan–Reines neutrino experiment . u Savannah River Site u γ u. u . u u n u. u u u . ν¯e from + u reactor ep¯ u . u u used the antineutrino flux from the u nuclear reactors of the Savannah u River Site (South Carolina). u u u u ...1956 u {w I Cafe Scientifique Neutrinos Thomas Gajdosik . u eννp−µ muon neutrino . the Alternating Gradient Synchrotron (AGS) u u . 1962 u u γ Leon Lederman u. u Melvin Schwartz . u Jack Steinberger u n u. u use the pions and kaons of the u u AGS. These dacays produce also . ν¯(anti)neutrinos;e from with a similar setup + u reactor ep¯ u like the Cowan–Reines experiment they . u u detect muons, but no electrons u ) the neutrinos coming from pions and u u kaons have to differ from the neutrinos u coming from the reactors. u u . 1956 1962 u {{w I Cafe Scientifique Neutrinos Thomas Gajdosik . eνp− Solar neutrino flux . the standard solar model (SSM) u . u u γ Around 1964 John Bahcall starts u. u to calculate the flux of neutrinos . u from the nuclear fusion processes in u n u. the sun, searching for all physical u processes that have an impact on u u the possibility to measure their flux . + u in an experiment on earth. ep¯ u . u ) the standard solar model (SSM) u u u u u u u . 1956 1964+ u {{{w I Cafe Scientifique Neutrinos Thomas Gajdosik . epartonsνp¯− / parton model . u Richard Feynman 1969 . u u γ u. u . u u n u. u u u . + u u a hadron is composed of point- ep¯ . u like constituents, called ”par- u tons”. The number of partons de- u pends on the probing energy u u ) parton distribution functions u u u . 1965 1969 u {{{{w I Cafe Scientifique Neutrinos Thomas Gajdosik . ν Homestake experiment . solar neutrino deficit u . u From 1970 to 1994 u γ u. Raymond Davis, Jr., u . measures the flux of u u τ− solar neutrinos using u. u the radio-chemical re- . u action u u . 37 37 − u ν + Cl ! Ar + e u . u but he only finds 1/3 of the flux u d predicted by John Bahcall ! u. u ) solar neutrino deficit u u u u . 1956 1970 till 1994 u { { { {{w {w I Cafe Scientifique Neutrinos Thomas Gajdosik . u ν τ lepton . u u . u u γ u. Martin Perl u . (SLAC-LBL) u u − 1975 τ u. u • using Mark I . (SLAC-LBL Magnetic Detector) u u u . – first 4π-detector u u . • comparing signal u u to background d u. u u u u u . 1956 1975 u { { { {{w {{ I Cafe Scientifique Neutrinos Thomas Gajdosik . u u ± eν− Zp hints for W - and Z-boson . u u u p p . u p u γ u. W u p u pu p u p u . u u . u Weak charged currents were known from u. u neutrino detection. g . u CERN announced the experimental obser- u d vation of weak neutral currents, shortly u. u after they were predicted by the electro- u weak theory of Abdus Salam, Sheldon u Glashow and Steven Weinberg. u u . 1956 1973 u { { { {{u {{{ I Cafe Scientifique Neutrinos Thomas Gajdosik . eν− neutrinoZ oscillations . p 1957 predicted by B. Pontecorvo u p p . u Super Kamiokande (SK) u γ p . announces first experimental u u evidence for atmospheric W p u neutrino oscillations in pu p 1998 u p u . Sudbury Neutrino Ob- u u servatory (SNO) pro- . u u. vides clear evidence of u g . neutrino flavor change in . u solar neutrinos in 2001 u d u. only then the solar neu- u trino puzzle was solved u u Nobel Price 2015 u u . 1957 1998 2001 2015 u {w { { {{ {{{{ {{{w w w I Cafe Scientifique Neutrinos Thomas Gajdosik u tau neutrino Zp Discovery by the DONUT collaboration (E872 Fermilab) u u p p . u p u νγτ u. u W . p u pu p τ− u. p u . u u . t u. u g . u u b u. u u u u u . 1956 2000 u { { { {{ {{{{ {w {{ { I Cafe Scientifique Neutrinos Thomas Gajdosik ”Todays” Understanding in the context of particle physics Cafe Scientifique Neutrinos Thomas Gajdosik How do we distinguish particles? • according to Special Relativity with mass and spin – particles with the same mass and the same spin are the same particles • by spin: a boson is different from a fermion – 4He behaves differently than 3He • by mass: a muon has a differnt mass than an electron – proton and neutron have nearly the same mass ∗ π+ and π− have exactly the same mass • by charge: – proton has a positive charge, the neutron is neutral ∗ π+ and π− have opposite charge F for neutrinos this is all (approximately) the same ! Cafe Scientifique Neutrinos Thomas Gajdosik . eν− Ordering principle: . discreet symmetries • Parity P . u u − − eL eR . – left-handed or right-handed . u u . τ− . • Charge Conjugation C µ− . u u . – particle or antiparticle . u u u . + e . 2 -.1 • Charge Q or Flavour 0 -1 3 3 d .