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A measurement of B0-B0 mixing in e+e- annihilation at 29 GeV


Weir, Andrew J. (1990) A measurement of B0-B0 mixing in e+e- annihilation at 29 GeV. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/v1j6-2c14.


This thesis describes a measurement of B0- B0 mixing in events produced by electron-positron annihilation at a center of mass energy of 29 GeV. The data were taken by the Mark II detector in the PEP storage ring at the Stanford Linear Accelerator Center between 1981 and 1987, and correspond to a total integrated luminosity of 224pb-1.

We used a new method, based on the kinematics of hadronic events containing two leptons, to provide a measurement of the probability, x, that a hadron, initially containing a b (b) quark decays to a positive (negative) lepton to be X = 0.17+0.15-0.08, with 90% confidence level upper and lower limits of 0.38 and 0.06, respectively, including all estimated systematic errors. Because of the good separation of signal and background, this result is relatively insensitive to various systematic effects which have complicated previous measurements.

We interpret this result as evidence for the mixing of neutral B mesons. Based on existing B0d mixing rate measurements, and some assumptions about the fractions of B0d and B0s mesons present in the data, this result favors maximal mixing of B0s mesons, although it cannot rule out zero B0s mixing at the 90% confidence level.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Physics
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Barish, Barry C.
Thesis Committee:
  • Unknown, Unknown
Defense Date:31 October 1989
Record Number:CaltechTHESIS:03182015-110658435
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8784
Deposited By: Bianca Rios
Deposited On:18 Mar 2015 20:03
Last Modified:09 Nov 2022 19:20

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