Neutrino shortage may signal new force. (Physics).When the subatomic particles called neutrinos slam into atomic nuclei, the invisible missiles don't behave quite as expected, new findings indicate. While the discrepancy is small, researchers say its significance could be great. It may point to a previously unrecognized fundamental force of nature.
So far, physicists have identified only four such forces: gravity, electromagnetism electromagnetism
Branch of physics that deals with the relationship between electricity and magnetism. Their merger into one concept is tied to three historical events. Hans C. , and the weak and strong forces. An analysis unveiled late last month at Fermi National Accelerator Laboratory Fermi National Accelerator Laboratory (Fermilab), physical science research center located near Batavia, Ill., est. 1968 as the National Accelerator Laboratory, renamed 1974 in honor of Enrico Fermi. It was built on the site of the former village of Weston. (Fermilab) in Batavia, Ill., suggests that another type of weak force may have influenced neutrinos in an experiment conducted there in 1996 and 1997.
During that time, experimenters fired an extraordinarily intense beam of the highest-energy neutrinos ever produced in a lab at steel plates in a 700-ton detector. The beam consisted solely of muon neutrinos, one of the three types of neutrinos. On the rare occasion when a muon neutrino struck an iron nucleus in the steel, the neutrino neutrino (ntrē`nō) [Ital.,=little neutral (particle)], elementary particle with no electric charge and a very small mass emitted during the decay of certain other particles. either would transform into a muon muon (my`ŏn), elementary particle heavier than an electron but lighter than other particles having nonzero rest mass. , which is a heavy cousin of an electron, or remain a neutrino.
After years of analysis of the neutrino-nucleus collisions, a surprise emerged: About 1 percent fewer collisions produced neutrinos than predicted by the standard model of particle physics.
If not just a fluke or evidence of some unexpected trait of neutrinos, the disparity may be the handiwork of a previously proposed extra force (SN: 1/15/00, p. 39), says Kevin S. McFarland of the University of Rochester The University of Rochester (UR) is a private, coeducational and nonsectarian research university located in Rochester, New York. The university is one of 62 elected members of the Association of American Universities. (N.Y.), a member of the research team that conducted the experiments. A heavy particle known as Z' would transmit the force, which would be about one-hundredth as strong as the weak force.
Recent upgrades to Fermilab's particle collider col`lid´er
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