Measurement of the B⁰B̅⁰ oscillation frequency using l^-D^*+ pairs and lepton flavor tags

Authors

T. Affolder, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California
Kenneth A. Bloom, University of Nebraska-LincolnFollow
Collider Detector at Fermilab Collaboration

Date of this Version

12-1-1999

Comments

Published by American Physical Society. Phys. Rev. D 60, 112004 (1999). http://prd.aps.org. Copyright © 1999 American Physical Society. Permission to use.

Abstract

The oscillation frequency Δm_d of B⁰B̅⁰ mixing is measured using the partially reconstructed semileptonic decay B̅⁰→l^- ν̅ D^*+X. The data sample was collected with the CDF detector at the Fermilab Tevatron collider during 1992–1995 by triggering on the existence of two lepton candidates in an event, and corresponds to about 110 pb^-1 of p̅p collisions at √s =1.8 TeV. We estimate the proper decay time of the B̅⁰ meson from the measured decay length and reconstructed momentum of the l^-D^*+ system. The charge of the lepton in the final state identifies the flavor of the B̅⁰ meson at its decay. The second lepton in the event is used to infer the flavor of the B̅⁰ meson at production. We measure the oscillation frequency to be Δm_d=0.516 ±0.099_-0.035^+0.029ps^-1, where the first uncertainty is statistical and the second is systematic.