Masses, lifetimes and production rates of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msup><mml:mi>Ξ</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"><mml:msup><mml:mover accent="true"><mml:mi>Ξ</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mo>+</mml:mo></mml:msup></mml:math> at LEP 1
Physics letters. B