Xi-c Baryon Definition

zīsē, sī-, ksē-
noun
Either of two subatomic particles in the baryon class, having a charm quark, a neutral or positive charge, masses of 4,834 and 4,826 times that of an electron, and average lifetimes of 3.5 × 10−13 and 9.8 × 10−14 second, respectively.
American Heritage