Violation in Mixing
Violation in Mixing
Violation in Mixing
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1.5 Determ<strong>in</strong>ation of « 37<br />
1.5 Determ<strong>in</strong>ation of «<br />
The angle « can be extracted from decays � � �ÙÙ, for example decays with two pions <strong>in</strong> the f<strong>in</strong>al state.<br />
The measurement of « is expected to be complicated if the pengu<strong>in</strong> contribution is not negligible.<br />
1.5.1 �È <strong>Violation</strong> us<strong>in</strong>g � decays <strong>in</strong>to non �È eigenstates and Extraction of « ignor<strong>in</strong>g<br />
pengu<strong>in</strong>s<br />
The angle « can be obta<strong>in</strong>ed by the measurements of �È -violat<strong>in</strong>g asymmetries <strong>in</strong> decays to f<strong>in</strong>al states that<br />
can be either �È eigenstates or not. In case of a �È eigenstate, Sec. 1.3 shows the relation between the<br />
asymmetry and the CKM elements. If a s<strong>in</strong>gle weak amplitude contributes to the decay taken <strong>in</strong>to account<br />
and if the pengu<strong>in</strong>s are negligible, then ����È<br />
����È � � and so:<br />
���È � ÁÑ���È ×�Ò ¡Ñ�Ø � (1.58)<br />
Then, ÁÑ� is cleanly related to one of the angle of the unitary triangle. In the particular case of � � ��,<br />
ÁÑ��� � ×�Ò «.<br />
In case the f<strong>in</strong>al state is not a �È eigenstate, four separate amplitudes can be def<strong>in</strong>ed [30]:<br />
� � � � � �� � ����� ��� � � � � � �� � ����� ���<br />
� � � � � � � � �� � �� �� � � � � � � � � � �� � �� �� �<br />
(1.59)<br />
Us<strong>in</strong>g the expressions <strong>in</strong> 1.24 and 1.25 for the physical states � Ô�Ý× Ø and � Ô�Ý× Ø together with the<br />
expressions of the coefficients � Ø and � Ø , one can evaluate the amplitudes:<br />
�<br />
���À��Ô�Ý× Ø � � �<br />
Ø� �ÅØ ¡Ñ�Ø ¡Ñ�Ø ��Å Ó× ���À�� � � ×�Ò � ���À�� �<br />
� �<br />
���À��Ô�Ý× Ø � � �<br />
Ø� �ÅØ ¡Ñ�Ø ¡Ñ�Ø ��Å Ó× ���À�� � � ×�Ò � ���À�� �<br />
where �Å is the phase of � -� mix<strong>in</strong>g com<strong>in</strong>g from Õ�Ô � � ��Å � ��È � . From these time-dependent<br />
amplitude and substitut<strong>in</strong>g Eq. 1.59 one can obta<strong>in</strong> the rates for � Ô�Ý× Ø and � Ô�Ý× Ø decay<strong>in</strong>g <strong>in</strong>to �:<br />
where<br />
� �<br />
�Ô�Ý× Ø � � � � Ø Ò<br />
� ¢<br />
Ó<br />
Ê Ó× ¡Ñ�Ø � ×�Ò �Å �� �� ×�Ò ¡Ñ�Ø<br />
�Ô�Ý× Ø � � � � Ø � ¢<br />
Ò Ó<br />
Ê Ó× ¡Ñ�Ø �×�Ò �Å �� �� ×�Ò ¡Ñ�Ø<br />
� ��� � ����<br />
�<br />
Ê � ��� � ����<br />
���� ����<br />
��<br />
��������<br />
��� � ��� �<br />
�<br />
(1.60)<br />
� (1.61)<br />
�È VIOLATION IN THE �� SYSTEM