Английский язык: Аннотирование и реферирование текста

203 Текст 6. A Hint of Axions An experiment may have seen an elusive new particle By Graham P . Collins ( Scientific American , July 2006 . P. 13 ) Named after a laundry detergent and originally proposed to clean up a problem with particle physics, axions are curious critters. Axions produced during the big bang could be lurking all around us, contribut- ing to the dark matter that constitutes 22 percent of the universe. Other axions, freshly formed inside the sun, could be streaming through us. And according to a paper published in March, laboratory-made axions might have been detected for the first time by an experiment in Italy known as PVLAS (polarization of the vacuum with a laser). Axions are posited to have exceedingly low mass – less than a millionth that of an electron – and are electrically neutral. They interact only very weakly with other particles, making detection difficult. But physicists predict that a tiny fraction of any photons passing through a magnetic field will change into axions. (That is how the sun is pre- dicted to produce them.) Indeed, the Italian experiment, based at the National Laboratories of Legnaro and led by Emilio Zavattini and Gio- vanni Cantatore of the INFN Trieste, saw evidence for axions in the behavior of a laser beam. The beam's polarization was rotated by 10 millionths of a degree after transiting 44,000 times back and forth through an extremely strong magnetic field. Such rotation is just the fingerprint expected if some photons converted to invisible axions, or more precisely, what physicists call axion-like particles. From its data, the PVLAS group infers the mass of the putative axions and how strongly they interact. Puzzlingly, however, the results contradict other observations and do not fit with constraints deduced from astrophysics. In particular, the CERN Axion Solar Telescope (CAST) ran for six months in 2003 and failed to detect any axions ar- riving from the sun. That result would seem to rule out a large swath of possible masses and interaction strengths, including the values seen by PVLAS. Furthermore, if axions interact as strongly as PVLAS indi-