The time dependence of B-d(-)(B) over bar(d)(-0) oscillations is measured by the ALEPH experiment at LEP, using three techniques; two of which are updates of previous measurements. In all cases the charge of the decaying b quark and its decay time are measured in one hemisphere of the event; the quark charge at production is tagged mainly using the opposite hemisphere. The first method uses the charge correlation between a D*(-) and a lepton in the opposite hemisphere; if no lepton is present, the produced quark charge is determined from the hemisphere charges. In the second method, the decay time is measured using a lepton in one hemisphere and the initial state is inferred from the opposite-hemisphere jet charge. The third method uses a lepton in each hemisphere. The data used were collected from 1991 to 1994. The combined result is Delta m(d)=0.446+/-0.032 ps(-1).
Improved measurement of the B-d(0)-(B)over-bar(d)(0) oscillation frequency
TRICOMI, Alessia Rita;
1997-01-01
Abstract
The time dependence of B-d(-)(B) over bar(d)(-0) oscillations is measured by the ALEPH experiment at LEP, using three techniques; two of which are updates of previous measurements. In all cases the charge of the decaying b quark and its decay time are measured in one hemisphere of the event; the quark charge at production is tagged mainly using the opposite hemisphere. The first method uses the charge correlation between a D*(-) and a lepton in the opposite hemisphere; if no lepton is present, the produced quark charge is determined from the hemisphere charges. In the second method, the decay time is measured using a lepton in one hemisphere and the initial state is inferred from the opposite-hemisphere jet charge. The third method uses a lepton in each hemisphere. The data used were collected from 1991 to 1994. The combined result is Delta m(d)=0.446+/-0.032 ps(-1).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
