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Violation in Mixing

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

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Offset (mrad) vs K cosθ<br />

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Offset (mrad) vs π cosθ<br />

BaBar Data (2001)<br />

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Sigma (mrad) vs K cosθ<br />

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Sigma (mrad) vs π cosθ<br />

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θ-θ exp K (1.75,1.875)<br />

BaBar (2001)<br />

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θ-θ exp K (1.875,2.0)<br />

θ-θ exp π (1.75,1.875) θ-θ exp π (1.875,2.0)<br />

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Figure 7-8. Left plots: distributions of � offsets (left) and resolutions (right) <strong>in</strong> the Run 2 � control<br />

sample as functions of track polar angle. Top plots are for kaons, bottom plots are for pions. Right plots:<br />

distributions of � � �ÜÔ Ó«×�Ø for kaons (top) and pions (bottom) <strong>in</strong> the Run 2 � control sample.<br />

The left (right) plots correspond to the momentum b<strong>in</strong> ���– ���� ��Î� ( ����– � ��Î� ).<br />

for the coefficients �� and ��� of the s<strong>in</strong>e and cos<strong>in</strong>e terms, respectively. Although the à à f<strong>in</strong>al state<br />

is a �È eigenstate, we treat this component as a pure lifetime. The functional form for the Ã� component is<br />

given by Eq. 7.9. We fix the parameters � and ¡Ñ�� to their PDG values [14] and take the error <strong>in</strong>to account<br />

as a systematic uncerta<strong>in</strong>ty. The background ¡Ø PDF is given by the triple-Gaussian resolution function<br />

Ê���, with the parameters def<strong>in</strong>ed <strong>in</strong> Table 7-7. The ¡Ø parameterization is summarized <strong>in</strong> Table 7-12, and<br />

the f<strong>in</strong>al set of free parameters <strong>in</strong> the maximum likelihood fit are listed <strong>in</strong> Table 7-13.<br />

7.7.2.1 Correlations between PDF variables<br />

An implicit assumption <strong>in</strong> the construction of the likelihood function is that the PDF dependent variables<br />

are uncorrelated. Table 7-14 summarizes the l<strong>in</strong>ear correlation coefficients for all pairs of Ñ�Ë, ¡�, �, � ,<br />

� , ¡Ø, and �¡Ø. Correlations greater than are highlighted.<br />

The correlation between Ñ�Ë and ¡� is not thought to have any significant impact on the fit (mostly because<br />

the MC correlation is <strong>in</strong>flated by the better ¡� resolution compared with data). The correlations between<br />

the � ��Ö�Ò�ÓÚ angles, and between � and ¡�, <strong>in</strong>Ã� and Ãà events is due to the underly<strong>in</strong>g momentum<br />

MARCELLA BONA

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