Violation in Mixing

110 Strategy and Tools for Charmless Two-body � Decays Analysis
Figure 4-8. Left plots: Ã-efficiency identification and �-contamination for SMS Loose selector as a
function of the momentum for tracks within �ÁÊ� acceptance. Right plots: ¯ ��� for low momenta
(� ����Î� ) and high momenta (� ����Î� ) as a function of Ó× �) for SMS Loose selector.
¯ Very Loose: Ä � �ÄÃ
¯ Loose: Ä Ã �ÖÄ� and Ä Ã � Ä Ô
¯ Tight and Very Tight: Ä Ã �ÖÄ� and Ä Ã �ÄÔ
¯ NotAPion: Ä � �ÖÄÃ and Ä � �ÖÄÔ,
where parameterization of Ö as function of momentum depends on the criteria. The counting analysis used
here as a cross check has been performed using the Loose selection. In the momentum region of interest
(above ����Î� ) this selection uses only the �ÁÊ� with two different Ö values: Ö � for momenta
� ����Î� and Ö � � for momenta � ����Î� . A track is considered a kaon when it satisfies the
Loose selection, otherwise it is considered to be a pion. To eliminate protons, an additional cut on the
���Ö�Ò�ÓÚ angle � � Ô �� � � is applied, where � Ô is the expected angle for a proton.
In order to measure the branching fraction of the Ã� and �� decays the efficiency and contamination of Ãidentification
need to be well known. These quantities are obtained using the � £ control sample described
in Sec. 4.4.1.
Left plots in Fig. 4-8 show the efficiencies ¯ ��� and ¯ ��� for the Loose selector as a function of the
momentum for tracks inside the �ÁÊ� acceptance. Table 4-4 reports the integrated efficiencies assuming a
flat momentum distribution between �� and �� ��� .
MARCELLA BONA