Cyg X-3: photinos, quark nuggets?
The exotic radiation was not found by equipment actively looking at Cyg X-3. It turned up in experiments set up to look for radioactive decay of the proton. (Some of the latest theories of physics require that the proton, contrary to previous belief, should decay radioactively.) Such decays would be extremely rare, so experiments to search for them consist of large masses of water, put deep underground to shield them from ordinary cosmic rays and other ambient radiation.
None of the proton decay experiments has yet seen proton decay, but the strange radiation from Cyg X-3 has appeared in two of them. One of these is a collaboration between the University of Minnesota in Minneapolis and Argonne (Ill.) National Laboratory and is located in the Soudan mine in northern Minnesota. The other, located in a tunnel under Mont Blanc, Europe's tallest mountain, is under the aegis of the CERN laboratory in Geneva and goes under the interesting acronym NUSEX.
What appear in these water tanks are actually muons, a well known variety of particle. Muons have too short a lifetime to have come themselves from Cyg X-3 but rather something that decays into muons near the earth has come from there. By their properties these muons cannot come from any decay of the ordinarily known progenitors. To come straight from Cyg X-3, the progenitor of the muons has to be electrically neutral -- if it were charged, the magnetic field of the galaxy would curve its path -- but for reasons of energy, neither neutrons nor gamma rays will fit.
"Such observations would require a new particle or a new physical process," write M.V. Barnhill Ill., T.K. Gaisser and Todor Stanev of the University of Delaware at Newark and Francis Halzen of the University of Wisconsin at MAdison in the Oct. 3 NATURE. They go on to suggest a new particle, quark nuggets. Quarks are supposed to be the elementary building blocks out of which most known particles are made. Theory also predicts that quarks could stick together in lumps that do not make up particles of the ordinary sort. The nuggets could be made in processes associated with a quark star, a star made up of a lot of quarks stuck together -- if such a thing happens to be at the heart of Cyg X-3. The quark nuggets would be produced in a charged form and accelrated by electromagnetic fields near the quark star and then neutralized on the way.
Another suggestion for the exotic radiation is photinos. One of the attempts to unify all of physics in a single theory are the supersymmetry theories, which propose that every known particle has a supersymmetric partner. The photino is the partner of the photon or particle of light. In the same issue of NATURE, V.J. Stenger of the University of Hawaii in Honululu suggests photinos. These photinos would be produced in very high energy processes that start with energetic protons produced by the source in Cyg X-3.
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|Author:||Thomsen, Dietrick E.|
|Date:||Oct 12, 1985|
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