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Anomalons Counting Neutrinos Muonium in a Vacuum

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Anomalons Counting Neutrinos Muonium in a Vacuum The Cabibbo picture is only sup­ search for anomalon alpha particles, and examined for the presence of posed to be approximate, but the without success. More anomalon three isotopes of technetium, includ­ emergence of a result so drastically evidence comes from a Minnesota ing two that result directly from the different to the predicted value is cosmic ray group using samples interaction of neutrinos with molyb­ puzzling. flown from balloons. denum. These isotopes, with half- Spin-related hyperon measure­ There is no shortage of theoretical lives ranging from 200 000 to four ments have a habit of giving unex­ candidate mechanisms. Many of million years, should provide a re­ pected results from time to time. these involve unusual quark configu­ cord of neutrino abundances over Hyperons produced in unpolarized rations, such as a 'demon' deuteron the millenia. hadron collisions tend to be polar­ involving three quark pairs instead of As well as finding any 'missing' ized. Some of the observed hyperon the conventional deuteron of two neutrinos emitted by the sun, such a magnetic moments do not fit other­ nucleons, each containing three study could reveal systematic varia­ wise successful theoretical models. quarks. tions in the sun's activity. Another possibility now receiving attention is the construction of direc- Anomalons Counting neutrinos tionally sensitive neutrino detectors Evidence continues to accumulate A new experiment by Los Alamos containing large amounts of material for 'anomalons' — some interesting researchers could go on to provide with polarized nuclear spins. and as yet unexplained behaviour ob­ new clues in the study of the neutri­ served in nuclear collisions. A num­ nos emitted by the sun. Muonium in a vacuum ber of experiments have found ex­ An appreciable flux of neutrinos tremely reactive secondary nuclear should be produced by the intense Muonium is an atomic state consist­ fragments close to the collision thermonuclear reactions deep in the ing of a positive muon and an 'orbital' point. The lifetime of these states is sun's interior which attain the enor­ electron. For atomic and chemical of the order of 10~~11 seconds, cer­ mous temperatures able to resist the purposes it is aptly described as a tainly stable against strong nuclear huge gravitational compression. The light isotope of hydrogen with about decays and long-lived by any nuclear flux of these neutrinos, which should one ninth of the hydrogen mass. Be­ standards. be measurable on earth, provides in cause it is composed of (supposedly) Anomalons (the name arose after principle a useful thermometer to pointlike particles with no strong in­ a mistyping of the word anomalous) measure the temperature of the teractions, it is a potentially useful are an order of magnitude more reac­ sun's interior. way of testing exact predictions. tive than ordinary nuclear matter of For many years, a Brookhaven ex­ Muonium is usually formed by the same mass. Nuclear excitations periment led by Ray Davis has been slowing down beams of positively which could produce such behaviour using a neutrino detector 5000 feet charged muons in matter. The inter­ typically live for 10~23 to 10-16 se­ below ground in a South Dakota lead action of this muonium with the tar­ conds. The 10"11 second anomalon mine to intercept these solar parti­ get material is exploited in the muon lifetimes defy comprehension. cles. But this study has only inter­ spin rotation technique (see, for ex­ Hints of such behaviour had been cepted a fraction of the expected ample, March issue, page 64). How­ seen in cosmic ray events some thir­ neutrino level. ever this interaction can be undesir­ ty years ago. Now it has been ob­ The Brookhaven experiment looks able if precision measurements on served by a number of teams using for neutrino-induced reactions more muonium itself are required. Recent heavy ion beams with energies or less as they occur. However the developments at LAMPF and at around 2 GeV/nucleon at the Berke­ Los Alamos study plans to look for TRIUMF have succeeded in produc­ ley Bevalac. A Berkeley/Ottawa col­ signs of neutrino interactions in fossil ing muonium in a vacuum by passing laboration has evidence from the in­ ores in which the products of millions low energy muon beams through thin teractions of iron and oxygen ions in of years of exposure to solar neutri­ foils. emulsion targets, and a Buffalo (New nos would be stored. According to relativistic (Dirac) York) group has examples from iron Residues from molybdenum ore electron theory, certain excited and argon beams. This team reports mined a mile below the earth's sur­ atomic states should have exactly no anomalons with iron beams at half face in Colorado's Red Mountain will the same energy. However this is not the energy, and has made a special be brought back to the Laboratory the case, and the tiny energy differ- 226 CERN Courier, July/August 1982 Around the Laboratories ence — the Lamb shift — is used as anticipated effect of the intermediate one of the standard tests of modern FERMILAB vector boson. The production of quantum electrodynamics. Because Tevatron II heavy quarks is greatly enhanced at it avoids the complications of pro­ higher energies. At the same time the tons, muonium provides a potentially gets under way combination of higher beam energies good laboratory for making precise and new detector technology will measurements. Preliminary measu­ This spring Fermilab was given the make it possible to study particles rements of the Lamb shift in muon­ go-ahead for Tevatron II, the project with lifetimes as short as 10~13 se­ ium have been made at TRIUMF, and to upgrade the Laboratory beam conds. As a result, it may be possible are consistent with theory. switchyard and experimental areas to study charm and bottom mesons In the most easily accessible ex­ for operation at 1000 GeV (1 TeV). in detail, and to start to look at tau ample of the Lamb shift, the lower of Broad unexplored energy regimes neutrinos. the two adjacent energy levels can­ will open for fixed target physics. For Tevatron II is one leg of the overall not decay directly and is thus me- example, the gain in the event rate of Tevatron triangle. The base is the tastable. This state has been ob­ energetic interactions and the dou­ Energy Saver/Doubler — the con­ served at TRIUMF. When a strong bled energy of the proposed muon struction of a superconducting accel­ electric field is applied, it is partially beam will allow expanded measure­ erator ring in the present main ring converted through the Stark effect to ments of the quark structure func­ tunnel. A fair fraction of the installa­ an adjacent state, which radiates tions of the nucleons and sensitive tion of the Energy Doubler is com­ down to the ground state. The inten­ tests of quantum chromodynamics plete. The remainder will continue sity of the emitted radiation depends predictions. Careful measurement of this summer. The second part of the on the degree of conversion high energy neutrino interactions will overall project, Tevatron I, is the achieved, and gives an indication of test the unified description of lep- construction of an antiproton source the Lamb shift. tons, including the predicted damp­ and other associated facilities to per­ Measurements of the muonium ing of the total event rates from the mit proton-antiproton collisions in flux from a variety of different foils are under way at TRIUMF and meth­ ods are being considered for precise measurements of muonium Lamb shifts. Tom Kirk (left), Project Manager of Fermilab's Tevatron II, seen with Deputy Project Manager Roger Dixon. (Photo Fermilab) CERN Courier, July/August 1982 227 .
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