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Violation in Mixing

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190 Analysis of the time-dependent �È -violat<strong>in</strong>g asymmetry <strong>in</strong> � � � � decays<br />

Fit # Æ�� ÆÃ� Ë�� ���<br />

1 �� �� ¦ � � ��� ¦ ���<br />

2 � � �� ¦ ��� � � ¦ ���<br />

3 � � � ¦ ��� � ¦ ���<br />

4 � � � � ¦ �� ��� ¦ ��<br />

5 � �� �� ¦ ��� � � ¦ ��<br />

6 �� � � ¦ � � � ¦ ���<br />

7 �� �� ¦ � � � ¦ ���<br />

8 �� ��� ¦ � � ��� ¦ ���<br />

9 � �� ��� ¦ � � � � ¦ ���<br />

10 � �� �� ¦ ��� ��� ¦ ���<br />

Average ��� ���� ����� � � ������ � ���<br />

Table 7-16. A set of ten �È fits on ��� fb equivalent cont<strong>in</strong>uum Monte Carlo with the correct proportion<br />

of �� and Ã� signal. The asymmetry <strong>in</strong>put values are Ë �� � �� and ��� � .<br />

7.8.4 Branch<strong>in</strong>g fraction fits<br />

Hav<strong>in</strong>g validated the analysis on toy and fully simulated Monte Carlo events, we fit without ¡Ø to validate<br />

the branch<strong>in</strong>g fraction portion of the likelihood. Table 7-17 summarizes fits to the Run 1, Run 2, and<br />

comb<strong>in</strong>ed samples. The yields for both Run 1 and Run 2 are consistent with the PRL branch<strong>in</strong>g fractions,<br />

and the background parameters for Ñ�Ë, ¡�, and � are consistent between the two datasets. To evaluate<br />

the effect of float<strong>in</strong>g the background PDF parameters we also show a fit where the parameters are fixed to<br />

theÕvalues obta<strong>in</strong>ed from the float<strong>in</strong>g fit. The contribution to the error on the �� yield can be estimated<br />

as �­Ó�Ø � ¬Ü � �� events, which is significantly less than the systematic error derived from the<br />

conservative procedure used for the PRL analysis.<br />

7.8.5 Lifetime and mix<strong>in</strong>g fits<br />

As a cross-check on the signal and background ¡Ø parameterizations we perform �È bl<strong>in</strong>d fits to the lifetime<br />

�, mix<strong>in</strong>g frequency ¡Ñ�� , and �È asymmetries <strong>in</strong> Run 1 and Run 2 data. When fitt<strong>in</strong>g only � and ¡Ñ��<br />

we fix Ë�� � ��� � <strong>in</strong> order to be <strong>in</strong>sensitive to �È asymmetry. For the �È fit we bl<strong>in</strong>d by add<strong>in</strong>g a<br />

random offset between ¦� and randomly flipp<strong>in</strong>g the sign of the asymmetries.<br />

Table 7-18 summarizes the fit results. We obta<strong>in</strong> values of � and ¡Ñ�� consistent with the PDG and fitt<strong>in</strong>g<br />

for these parameters does not significantly change the yields. Table 7-19 summarizes fits float<strong>in</strong>g �, ¡Ñ�� ,<br />

and the bl<strong>in</strong>ded �È asymmetries Ë�� and ���. Aga<strong>in</strong>, all results for � and ¡Ñ�� are consistent with the<br />

PDG.<br />

MARCELLA BONA

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