A method to estimate the momentum and the decay proper time of the B mesons from their hadronic and semileptonic decays

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 302; no. 1; pp. 119 - 134
• Main Author: Defoix, Christian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.1991
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/0168-9002(91)90500-P

A method, which substitutes for the usual kinematical fit, is developed to estimate the momentum, and hence the decay proper time, of the B mesons produced in the Z 0 decay in the experimental context of LEP. This method tries to use the maximum information contained in the charged particle measurement for identification from such a device as DELPHI. Constrained and unconstrained final states involving a D meson are treated in a similar way. Monte Carlo simulation of the method shows that the resulting average uncertainty in the proper time, due to B momentum estimation, reaches 7% for the hadronic decay events and 13% for the semileptonic ones, for half the events processed by the method. From such results, analysis of topics such as B s 0- B s 0 oscillations can be reasonably envisaged at LEP.