The STORY of the Neutrino 19 30 1956 1958 1968 1975 1989 1998 2001 2005 In a letter to the Two American Maurice Goldhaber, An experiment deep A new lepton, tau, Experiments at CERN Using a detector with MINOS will begin the attendees of a physics scientists, Frederick Lee Grodzins, and underground in the is discovered by a and at Stanford show Physicists from the 1000 tons of heavy detailed study of the conference in Tübingen, Reines and Clyde Andrew Sunyar at Homestake mine in group led by physicist that there exist only SuperKamiokande water, the SNO neutrino oscillations Germany, Wolfgang Cowan, report Brookhaven National South Dakota makes Martin Perl at the three species of light experiment in Japan experiment in Sudbury, previously observed present data on the Pauli proposes as a the first direct evidence Laboratory demonstrate the first observation of Stanford Linear (or massless) neutrinos. Ontario demonstrates from atmospheric deficit in muon “desperate remedy” for neutrinos. They use that the new neutrino neutrinos from the sun. Accelerator Center. Thus , , and must that the deficit in solar neutrinos. Using 120 νe νµ ντ neutrinos produced in the existence of a a fission reactor as has left-handed helicity, But experimenters see Experiments performed complete this class of the Earth’s atmosphere. neutrinos is due to GeV protons from the new neutral particle to a source of neutrinos meaning that it spins far fewer neutrinos shortly afterward particles. This direct The data suggest that neutrino oscillations. Fermilab Main Injector explain the apparent and a well-shielded along the direction of than solar models provide strong evidence measurement verifies the deficit varies ▼ as its source, MINOS energy nonconservation 1933 scintillator detector 1957 its motion in the sense 1962 had predicted. In 2002 1973 that there also exists a 1987 strong suggestions 1990 depending on the 19 99 2002 will send a beam in radioactive decays. nearby to detect them. of a left-handed screw. Ray Davis wins the third species of neutrino, previously deduced distance the neutrinos of muon neutrinos Enrico Fermi proposes An Italian physicist, A group of scientists An international team Large underground Two experiments, The neutrino oscillation During the next few Thirty-nine years later The experiment helps Nobel Prize for this the tau neutrino, ντ. from the cosmological travel—an indication The Main Injector through the earth to years, scientists “neutrino” as the name Reines’s work is Bruno Pontecorvo, living to distinguish among from Columbia University pioneering work. working at CERN, the In 1995, Perl wins the water detectors in the measurements. SAGE in the USSR that neutrinos oscillate at Fermilab begins parameters measured by the Soudan mine in elaborate Pauli’s theory for Pauli’s postulated recognized with the in the USSR, formulates different forms of weak and Brookhaven National European Laboratory Nobel Prize for this Kamioka mine in Japan and GALLEX in Italy, and have mass. In operation. The the SNO experiment are northern Minnesota. and conclude that the particle. He formulates Nobel Prize. a theory of neutrino interactions. Laboratory perform for Particle Physics, discovery. and in the Morton salt are set up to look at 2002, Masatoshi combination of its confirmed by the ▼ new particle must be a quantitative theory ▼ “oscillations.” He shows the first accelerator in Geneva, Switzerland, ▼ mine in the U.S. detect neutrinos from the Koshiba wins the 2002 high-intensity particle KamLAND experiment, very weakly interacting of weak particle that if different species neutrino experiment uses a bubble chamber the first neutrinos from sun. The detection Nobel Prize for his beam and an energy of which observes a deficit and extremely light. interactions in which of neutrinos exist, they and demonstrate the to observe the first a supernova, SN1987A. of these neutrinos in leadership in the 120 GeV allows a new of neutrinos from ▼ the neutrino plays an might be able to existence of two example of a “neutral subsequent years is the SuperKamiokande generation of neutrino Japanese reactors. integral part. oscillate back and species of neutrinos, current” event. first proof of energy experiment. experiments that will ▼ forth between the electron neutrino, Observation of this production by fusion ▼ continue to probe some of nature’s most different species. νe, and the muon new interaction lends of hydrogen in the fundamental questions. neutrino, νµ. In 1988, strong support to a sun—but still, far fewer Jack Steinberger, Leon unified theory of weak neutrinos are detected Lederman, and Mel and electromagnetic than expected. Schwartz win the Nobel interactions proposed ▼ Prize for this discovery. a few years earlier ▼ by Sheldon Glashow, Abdus Salam, and Steven Weinberg. Shortly afterward, scientists at Fermilab confirm the discovery. ▼ GALLEX Soudan The SNO experiment under construction Stanford Linear Minn. Accelerator Center Wis. Frederick Reines Wolfgang Pauli J. Steinberger, K. Goulianos, J. Gaillard, N. Mistry, G. Danby, Fermilab W. Hayes, L. Lederman, M. Schwartz Ill. December 4, 1930 MINOS collaboration Dear Radioactive Ladies and Gentlemen, As the bearer of these lines, to whom I graciously ask you to listen, will explain to you in more detail, how because of the “wrong” statistics of the N and Li6 nuclei and the continuous beta spectrum, I have hit upon a desperate remedy to save the “exchange theorem” of statistics and the law of conservation of energy. Namely, the possibility that there could exist in the nuclei electrically neutral particles, that I wish to call neutrons*, which have spin 1/2 and obey the exclusion principle and which 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 masses. The continuous beta spectrum would then become understandable by the assumption that in beta decay a neutron is emitted along with the electron such that the sum of energies of neutron and electron is constant. I admit that my remedy could seem improbable because one should have seen those neutrons much earlier if they really exist. But only the one who dares can win and the difficult situation, due to the continuous structure of the beta spectrum, is lighted by a SuperKamiokande experiment remark of my honored predecessor, Mr. Debye, who told me recently in Bruxelles: “Oh, it’s best therefore, not to think about this at all, like new taxes”. Therefore, every solution to the issue must be discussed seriously. Thus, dear radioactive people, examine and judge. Unfortunately, I cannot appear in Tübingen personally since I am indispensable here in Zurich because of a ball on the night from 6 to 7 of December. With my best regards to you, and also to Mr. Back. Your humble servant, A neutral current event observed in the W. Pauli * Pauli originally called the new particle the Gargamelle bubble chamber at CERN neutron. Later, Fermi renamed it the neutrino. Enrico Fermi electron neutrino muon neutrino tau neutrino A 1930 letter from Wolfgang Pauli to colleagues in Tübingen, Germany described a “desperate remedy” –the neutrino. MINOS collaboration This is a 2004 update and modification of a poster prepared in 2000 by Fermilab..