Английский язык: Аннотирование и реферирование текста

204 cates, they should be produced in large quantities in stars, causing stars to grow old much faster than they are known to. Such considerations "put the bar pretty high before one can accept the PVLAS results," says axion expert Pierre Sikivie of the University of Florida and CERN. On the other hand, he adds, "these people are very competent, and they have worked on it a long time." By all accounts, the PVLAS research- ers have been careful to exclude effects that could be confounding the data; moreover, in work that is not yet published, the group has also obtained consistent results with a different laser. Some theorists have already proposed ways to reconcile the PVLAS results with those of CAST and other astrophysical limits. Only further experiments will determine the truth. If the PVLAS results are correct, then axions should appear in an experiment known as "shining a light through a wall." The idea is this: A laser beam is sent through a strong magnetic field at an opaque wall. Some of the photons in the beam are converted to axions, which pass through the wall. On the other side, another magnetic field induces a small fraction of the axions to convert back to photons, which can be detected. Such an ex- periment, using a large, strong magnet and sensitive photon detectors, would convincingly confirm (or refute) the PVLAS results in a matter of minutes. Research groups, including the PVLAS team, are gearing up to perform that experiment. By the end of the year the axion could be a firm addition to the particle menagerie – or back on physicists' most-wanted list. Saving Symmetry Physicists originally proposed the axion as part of a scheme to explain why the strong nuclear force preserves so-called CP symmetry, which relates the properties of particles and antiparticles. Calculations using the Standard Model of particle physics showed that the strong force could preserve CP only if a certain parameter in the theory was zero, and yet quantum effects tend to make the parameter nonzero. In 1977 Helen R. Ouinn and Roberto D. Peccei, then at Stanford Univer-