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Kobzarev and Lev Okun in Russia, transitions are possible analogues of greatly contributed to the understand­ and by Tom Kibble of London's cosmic seeds. ing of the nucleon structure in terms Imperial College, is that the initial of quarks, antiquarks and gluons. phase transition in the proto-Universe P.C. Hendry etal, Nature, Vol. 368, Furthermore, because of the low could have contained defects - tiny p. 315 (24 March 1994) event rate at the low neutrino energy, regions of space trapped in the 'old' most of the E-734 results have been high energy phase. These defects superseded by the more precise re­ could have gone their own way, Bookshelf sults obtained by higher energy neu­ developing into separate structures trino experiments at CERN and which helped to seed the subsequent Neutrino Interactions with Electrons Fermilab, however with the excep­ evolution of galaxies into clusters and and Protons - Edited by Alfred K. tions of the limits on neutrino mixing sheet-like 'superclusters'. Mann, published by the American and of the measurement of the neu­ When this happened just 10~34 Institute of Physics (ISBN 1-56396- tral current cross-section for neutrino second after the Big Bang, the 228-4) and antineutrino elastic scattering. It energy densities were out of reach of is not clear to me why the American anything that can ever be recreated Subtitled 'an account of an Experi­ Institute of Physics has chosen to directly on Earth, and scientists, for mental Program in Particle Physics in publish this book in a series 'Key whom ingenuity is an everyday tool, the 1980s', this book is a collection of Papers in Physics'. have to be especially resourceful. 13 reprinted papers presenting In 1985 W.H. Zurek of Los Alamos experimental results from experiment Luigi Di Leila suggested experiments to look for E-734 originally proposed in 1978 to signs of such defects in model measure the elastic scattering of systems, for example the delicate neutrinos and antineutrinos from phase transitions of superfluid electrons and protons using the helium-4 transforming into a normal neutrino beam at the Alternating fluid at about 2K. In this way labora­ Gradient Synchrotron (AGS) at tory studies could be used as models Brookhaven National Laboratory. for the infant Universe. This experiment took data during Subsequent experiments saw the 1980s and the apparatus was suggestions for such defects in dismantled in 1990. Its main results another delicate system, the rod-like cover measurements of the weak molecules of liquid crystals. Now a mixing angle, and some measure­ British group (Lancaster/Exeter) has ments which were not in the original seen signs in a liquid helium-4 proposal, such as limits on the system. With a sample of highly pure electromagnetic properties of the (possibly perfect) helium-4, the team muon neutrino and on the mixing hoped to avoid problems with defects between electron- and muon-neutri- from nucleation around impurities. nos. The collaboration, with 35 One problem with such cryogenic physicists participating, included experiments is that any defects are Osaka and KEK and was the earliest not easy to spot. The trick is to detect formal collaboration in high energy them through the attenuation of physics between American and sound waves across the 4-millimetre Japanese institutions. space of the experiment. The ob­ This book gives only a very partial served strong attenuation suggests account of neutrino physics in the the creation of an excess of vortex- 1980s. Because of the relatively low type activity, difficult to explain by neutrino energy of only few GeV, E- hydrodynamics alone. 734 physics did not include the study These defects induced by phase of deep inelastic scattering which has

28 CERN Courier, June 1994