Physicists have long wondered why no elementary particle discovered so far contains more than three of the fundamental building blocks known as quarks. Several recent findings have suggested particles with greater quark numbers (SN: 12/13/03, p. 381: Available to subscribers at Hints emerge of a four-quark particle), but other data haven't supported some of those findings.
Now, some physicists at the HERA particle collider at Germany's Deutsches Electronen-Synchrotron (DESY) laboratory in Hamburg have unveiled evidence for a five-quark particle—only the third such pentaquark tentatively sighted. But other researchers at DESY looking at other data say they detect no trace of the purported pentaquark.
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