Speaker
Mr
Marc Grabalosa Gandara
(Depto. d' Estruc. i Cons. de la Mat-Facultad de Fisica-Universid)
Description
To do precise CP violation measurements, it is necessary a very accurate determination of the flavour of the B-meson. This contribution explains and summarizes the flavour tagging performances for the LHCb experiment. This is obtained through a combination of several methods, based on different signatures, as for example the charge of decay products or the vertex charge of the opposite B. The probability of a tag to be wrong, called wrong tag fraction "\omega", dilutes the observed asymmetry by a factor "1-2\omega", therefore is necessary to optimize for "\omega" along with the efficiency for one event to be tagged, what is usually referred to as the effective efficiency "E_{tag}(1−2\omega)^2". The use of control channels, which are decays to flavour-specific final states, will allow to determine "\omega", which is then used as an input for the determination of CKM angles. To improve the tagging algorithms, we have implemented multivariate analysis tools which improve the efficiency and purity of the tagging.
Author
Mr
Marc Grabalosa Gandara
(Depto. d' Estruc. i Cons. de la Mat-Facultad de Fisica-Universid)
