Violation in Mixing

138 Measurement of Branching Fractions for � ¦ � Ã � ¦ decays
We find good agreement between the SMS selector and the global likelihood fit using the �ÁÊ� PDF’s.
We have also checked that the asymmetries are compatible with zero in the on-resonance upper and lower
side bands, in the off-resonance data and in continuum Monte Carlo.
In on-resonance lower side-band, we have 4529 events: fitting not using ¡� PDF and fixing the signal
asymmetries, we get
Æ Ë
Ã Ë �
� ��
Æ Ë
Ã Ë Ã �
Æ �
Ã Ë �
Æ �
Ã Ë Ã
� �
Ã Ë �
� �
Ã Ë Ã
���
�� ×Ø�Ø
��
×Ø�Ø
� �� �� ����
��� ×Ø�Ø
� ����� ���
���� ×Ø�Ø
� � ¦ � ×Ø�Ø
� � � ¦ � � ×Ø�Ø
We see no asymmetry in the background and no statistically significant signal. To evaluate the cross-feed of
background into signal events, we check on off-resonance data in the signal band, using ¡� PDF too: we
get
Æ Ë
Ã Ë � �
Æ Ë
Ã Ë Ã �
Æ �
Ã Ë �
Æ �
Ã Ë Ã
� �
Ã Ë �
� �
Ã Ë Ã
�
�
� � �
� �
×Ø�Ø
×Ø�Ø
���
��� ×Ø�Ø
���
��� ×Ø�Ø
� � ¦ � �� ×Ø�Ø
� � �� ¦ � �� ×Ø�Ø
Finally, we have built samples of continuum Monte Carlo events with different amounts of signal and
background and predefined asymmetries (including in the sample different amount of positive and negative
charged candidates) and we have checked that the fit returns the correct yields and asymmetries.
Table 5-6 shows that the fit always returns the correct number of signal events within � and that there is
less than cross-feed to the other Ã Ë � channel or to background events. Table 5-7 shows tests on samples
of continuum MC with fixed charge asymmetry: the fit returns the value of the asymmetry with very good
agreement.
5.5.4 Systematic uncertainties
The amount of background and signal are both allowed to fluctuate within Poissonian statistics in the fit
itself. Thus it is not necessary to estimate a systematic uncertainty from the background normalization. The
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