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Violation in Mixing

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7.7 The maximum likelihood analysis 177<br />

Parameter Run 1 Breco Run 2 Breco MC Breco<br />

Scale (core) �� ¦ � �� � � ¦ � � � � ¦ �<br />

Æ ¡Ø lepton (core) � ¦ � � � �� ¦ � � � � ¦ �<br />

Æ ¡Ø kaon (core) � ¦ � �� � �� ¦ � �� � � ¦ � �<br />

Æ ¡Ø NT1 (core) � �� ¦ � �� � �� ¦ � � � � ¦ � �<br />

Æ ¡Ø NT2 (core) � �� ¦ � � � �� ¦ � � � � ¦ �<br />

Æ ¡Ø notag (core) � � ¦ � �� � �� ¦ � � � ¦ � �<br />

Scale (tail) � ¦ � � ¦ � �� �� ¦ � �<br />

Æ ¡Ø (tail) �� �� ¦ ���� ���� ¦ � � ���� ¦ � �<br />

�(tail) � � ¦ � � � � ¦ � � � � ¦ � �<br />

�(outlier) � ¦ � � ¦ � � � ¦ �<br />

Table 7-10. Parameters for Ê×�� obta<strong>in</strong>ed from the Run 1 and Run 2 Breco tagged + untagged samples. The<br />

Breco MC results are shown for comparison.<br />

7.7 The maximum likelihood analysis<br />

An unb<strong>in</strong>ned maximum likelihood fit is used to simultaneously extract yields and �È asymmetry parameters<br />

from comb<strong>in</strong>ed tagged and untagged � � sample. The only new feature of the fitt<strong>in</strong>g technique relative to<br />

the branch<strong>in</strong>g fraction analysis is the addition of a PDF describ<strong>in</strong>g the time dependence <strong>in</strong> each component<br />

and tagg<strong>in</strong>g category.<br />

7.7.1 Likelihood function<br />

The overall construction of the likelihood function Ä is similar to the branch<strong>in</strong>g fraction analysis. For this<br />

analysis, the sample consists of signal and background components for the three species (��,Ã�, and ÃÃ),<br />

separated by the flavor and category of the tag side. In addiction to the usual variables Ñ�Ë, ¡�, the Fisher<br />

discrim<strong>in</strong>ant � and the � ��Ö�Ò�ÓÚ angle, the ¡Ø measurement facilitates provides additional background<br />

rejection.<br />

The probability �� for a s<strong>in</strong>gle event � <strong>in</strong> tag category is the sum of probabilities over all components,<br />

�� � ��<br />

Æ � �� È ��<br />

��<br />

ÆÃÃ<br />

Æ �ÃÃÈ ÃÃ<br />

��<br />

ÆÃ�<br />

Æ �Ã�<br />

���<br />

Æ � ��� È ���<br />

��<br />

Æ�ÃÃ<br />

Æ � �ÃÃ È �ÃÃ<br />

��<br />

�Ã� È Ã �<br />

��<br />

�� ��<br />

�<br />

Æ<br />

��Ã� È �à �<br />

��<br />

(7.10)<br />

ANALYSIS OF THE TIME-DEPENDENT �È -VIOLATING ASYMMETRY IN � � � � DECAYS

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