F. TASNÁDI LINKÖPING UNIVERSITY THEORETICAL PHYSICS NEUTRINO OSCILLATIONS & MASS the fundamental discoveries in physics con4nues 1
CONGRATULATIONS - NOBEL PRIZE IN PHYSICS 2016 the secrets of exotic matter /quantum physics becomes visible in the cold/ David J. Thouless F. Duncan M. Haldane J. Michael Kosterlitz 2
ONE WAY OF DOING FUNDAMENTAL PHYSICS LHC 27 KM Higgs boson the God particle 125 GeV 4 July 2012 STANDARD MODEL 3
ANOTHER WAY OF DOING FUNDAMENTAL PHYSICS SUSY supersymmetry fermions bosons (super)string theory 4
PARTICLE WORLD - THE STANDARD MODEL /1970 -???/ neutrinos flavours 5
METAMORPHOSIS IN THE PARTICLE WORLD - NOBEL 2015 The Nobel Prize in Physics 2015 recognises Takaaki Kajita in Japan and Arthur B. McDonald in Canada, for their key contributions to the experiments which demonstrated that neutrinos change identities (flavours). This metamorphosis requires that neutrinos have mass. The discovery has changed our understanding of the innermost workings of matter and can prove crucial to our view of the universe. http://www.nobelprize.org Takaaki Kajita Arthur B. McDonald 6
SOURCES OF NEUTRINOS Trillions of neutrinos passing through our bodies every second almost all of these are produced in fusion reactions in the Sun's core. Solar neutrinos Atmospheric neutrinos Other sources: Big Bang cosmic rays Supernovas 7
WHAT IS A NEUTRINO? - THE POLTERGEIST PARTICLE beta decay: energy conservation: 1929, Niels Bohr: possible limitation of the conservation theorems 1930: W. Pauli s letter: Dear Radioactive Ladies and Gentlemen there could exist electrically neutral particles, which I will call neutrons, that have spin 1/2 and obey the exclusion principle and that further differ from light quanta in that they do not travel with the velocity of light. The mass of the neutrons should be of the same order of magnitude as the electron mass and in any event not larger than 0.01 proton mass. 8
WHAT IS A NEUTRINO? - THE REAL PARTICLE 1931: The name neutrino by E. Fermi the Italain little neutral one 1934: The theory of beta decay by E. Fermi - (anti)neutrinos are included, produced! 1934, Niels Bohr: I don t yet feel fully convinced of the physical existence of the neutrino. 1956: Poltergeist is OVER F. Reines & C. Cowan detect the trace of (anti)neutrino scintillation detector Reines & Cowan 1958: neutrinos are ALWAYS left-handed 9
THE HANDEDNESS - THE VAMPIRE NEUTRINO PARTICLE momentum vs. spinning = handedness ~p ~p ~S~S ~ S neutrino mirror 1957, Abdus Salam: On reflecting a neutrino in a mirror, one sees nothing. 10
THE MASS - NO AGE OF THE NEUTRINO special relativity: massive particle can NEVER travel at the speed of light left-handed A two-handed v A MASSLESS NEUTRINO B right-handed Using massless particles in Dirac s equations violates left-right symmetry and results in two components equation - neutrino (left) & antineutrino (right). 11
THE FLAVOURS- THE DIFFERENT NEUTRINOS 1937: the muon or heavy electron from cosmic ray 1949: pion, Yukawa s particle Bruno Pontecorvo in Dubna - investigate the muon decay: µ! e + µ! e +2 conserve the muon-ness n! p+e + TWO TYPES OF NEUTRINO e, µ conserve the electron-ness 1975: a new lepton was found: the tau conserve tau-ness THREE FLAVOURS OF NEUTRINO e, µ, 12
WHAT IS A NEUTRINO? - IN THE STANDARD MODEL MASSLESS & LEFT-HANDED VAMPIRE standard model NEUTRINO ei µi i electron-flavour muon-flavour tau-flavour 13
MASS EIGENSTATES - SHORT QUANTUM MECHANICS special relativity, energy & momentum conservation: particle mie i m(t) particle stays in this mass eigenstate NO OSCILLATION between different E 2 = p 2 c 2 + m 2 c 4 E,p! m mi states. f 1 i particle spontaneously f 1 i, f 2 i ARE NOT MASS EIGENSTATES! f 2 i It is nonsense to speak about the mass if the particle is characterised by f i quantum numbers! 14
BECAUSE ONLY PARTICLE WITH MASS CAN OSCILLATE /1957, B. Pontecorovo suggests neutrino oscillation/ neutrino µi ei spontaneously ei, µi ARE NOT MASS EIGENSTATES! ei = P e µi = P j j m jie i m j (t) µ j j m jie i m j (t) /coherent superposition/ Flavour oscillation can happen only if the mass eigenvalues are different! The zero eigenvalue is excluded by the fact that all neutrinos are oscillating. W e = coherent superposition of mass states NEUTRINOS e + HAVE MASS 15
SOLAR (E-)NEUTRINO PROBLEM (1968) - HOMESTAKE EXP. SK: Super Kamiokande SNO: Sudbury Neutrino Observatory deficit of solar neutrinos theoretical rate: 8.5 ± 0.9 SNU Standard Solar Model experimental rate: 2.56 ± 0.32 SNU SNU: Solar Neutrino Unit 1 SNU = 1 reaction per 10 36 target per second) p+p! 2 H+e + + e 8 B! 8 Be +e + + e NEUTRINO OSCILLATION? 16
EXPENSIVE DEEP & DARK SCIENCE IN JAPAN & CANADA SUPER KAMIOKANDE: - operational in 1996 (started 1991) - zinc mine - 1000 m below Earth surface - 50,000 tonnes of pure water (light beam can travel 70 m before intensity is 1/2) - more than 13,000 light detectors to detect Cherenkov radiation - 8 B solar neutrinos - muon neutrinos (atmospheric) SUDBURY NEUTRINO OBSERVATORY: - operational in 1999-1,000 tonnes heavy-water and for extra shielding ultra-pure water - 9500 light detectors - all flavours of neutrinos (including 8 B solar neutrinos) 17
SUPER KAMIOKANDE (SK) KAMIOKA, JAPAN 18
SUDBURY NEUTRINO OBSERVATORY (SNO) CANADA, ONTARIO photo: Lawrence Berkeley Nat'l Lab 19
ICECUBE - ANTARCTICA 20
ICECUBE - THE LABORATORY 21
ATMOSPHERIC NEUTRINOS IN SK - YEAR 1998 x +e! x +e ISOTROPIC FLUX long( µ ) short( µ ) 50% The nobel prize in physics 2015, Popular science background 22
NEUTRINOS IN SNO - YEAR 2001 reaction-1: reaction-2: x +e! x +e e + 2 H! e +p+p x + 2 H! x +p+n reaction-1 1( e, Sun) reaction-2 2(all, Sun) 2(all, Sun) = theory ( e, Sun) The nobel prize in physics 2015, Popular science background 23
NEUTRINO MASS - CONTRADICTIONS! STANDARD MODEL? Contradiction between left-handedness and mass! Solution? 1) right-handed neutrinos are not detected 2) extremely weak weak-interaction Dirac neutrino 6= superstring theory (11 dimensions) mass by Higgs mechanism experimentalists Majorana neutrino = matter=antimatter mass by Higgs mechanism theorists supersymmetry (SUSY), string theory, etc 24
FUNDAMENTAL PHILOSOPHY 25
WE NEED THE TECHNOLOGY TO MAKE IT 26
CMS DETECTOR THANK YOU 27
MUON AND TAU NEUTRINOS (SNO WITH SK) reaction-1 3.26 reaction-2 28
THE AMAZING NEUTRINOS - PROPERTIES - In our Universe what we see are stars, galaxies, but what we do not see that the Universe is filled with neutrinos, the second most abundant particles in the Universe after photons; every cm 3 of space contains around 300 neutrinos. - Trillions of neutrinos are passing through our bodies every second almost all of these are produced in fusion reactions in the Sun's core - interact only with the weak force. H 2 O 1.7 10 17 m 10 6 d(sun-earth) Pb 1.5 10 16 m - Direct mass measurements: massless? 5 10 5 m e m e m p 1840 - Indirect mass measurements: m > 0 29