Speaker
Prof.
David London
(Universite de Montreal)
Description
The decay Bs -> J/psi phi is used for measuring 2beta_s, the phase of Bs-Bsbar mixing. The amplitude for this decay is dominated by the colour-suppressed tree diagram, but also contains "penguin pollution" (PP) due to gluonic and electroweak penguin diagrams. The PP leads to a theoretical error in the extraction of 2beta_s from the data. In the SM, it is estimated that the PP is negligible, but there is some uncertainty as to its exact size. Now, the measured value of 2beta_s is small, in agreement with the SM, but still has significant experimental errors. When these are reduced, if one hopes to be able to see clear evidence of new physics, it is crucial to have the theoretical error under control. In this talk, I describe how a modification of the angular analysis currently used to measure 2beta_s in Bs -> J/psi phi can be used to reduce the theoretical error due to PP.
Author
Prof.
David London
(Universite de Montreal)
