AN elusive member of the meson family of particles may at last have been
detected.
Mesons contain a quark and an antiquark. Of the 15 ordinary types thought to
exist, physicists had found 14 in the debris of collisions in particle
accelerators.
Now the last of the family鈥攎ade of a charm quark and an antibottom
quark鈥攕eems to have turned up in collisions at Fermilab near Chicago.
Shin-Hong Kim at Tsukuba University in Japan says the particle, which weighs
more than six protons, lives for 0.46 picoseconds.
