ALEPH's published measurement of R-b = Gamma(Z --> b (b) over bar)/Gamma(Z --> hadrons) using a lifetime tag is updated using the full LEP 1 data sample. Considerable effort has been devoted to understanding systematic effects. Charm background is better controlled by combining the lifetime tag with a tag based on the b/c hadron mass difference. Furthermore, the algorithm used to reconstruct the event primary vertex is designed so as to reduce correlations between the two hemispheres of an event. The value of R-b is measured to be 0.2167 +/- 0.0011(stat) +/- 0.0013(syst). (C) 1997 Published by Elsevier Science B.V.
|Autori interni:||CREANZA, Donato Maria|
MAGGI, Giorgio Pietro
|Titolo:||A measurement of R-b using a lifetime-mass tag|
|Rivista:||PHYSICS LETTERS. SECTION B|
|Data di pubblicazione:||1997|
|Digital Object Identifier (DOI):||10.1016/S0370-2693(97)00406-1|
|Appare nelle tipologie:||1.1 Articolo in rivista|