28.12.2012 Views

Violation in Mixing

Violation in Mixing

Violation in Mixing

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

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

Sample � ¡Ñ�� Ë�� (bl<strong>in</strong>d) ��� (bl<strong>in</strong>d)<br />

Run1 �� ¦ � � ��� ¦ � �� �� ¦ ��� ��� ¦ ���<br />

Run2 ��� ¦ � �� � ¦ � � ��� ¦ � � �� ¦ ��<br />

Run1 + Run2 �� ¦ � ��� ¦ � �� ��� ¦ ��� �� ¦ ���<br />

Table 7-19. Summary of fits float<strong>in</strong>g �, ¡Ñ��, and the bl<strong>in</strong>ded �È asymmetries Ë�� and ���. Units are<br />

Ô× for � and �� Ô× for ¡Ñ��.<br />

-2 (log L - log L 0 )<br />

7.9 Results<br />

4<br />

3<br />

2<br />

1<br />

BABAR<br />

0<br />

-1 -0.5 0 0.5 1<br />

Sππ -2 (log L - log L 0 )<br />

4<br />

2<br />

0<br />

BABAR<br />

-1 -0.5 0 0.5<br />

Cππ Figure 7-15. Scans of the likelihood function vs. Ë ��, ���, and �Ã�.<br />

-2 (log L - log L 0 )<br />

25<br />

20<br />

15<br />

10<br />

5<br />

BABAR<br />

0<br />

-1 -0.5 0 0.5 1<br />

ACP The unbl<strong>in</strong>ded fit results are shown <strong>in</strong> Tab. 7-20 Figure 7-15 shows scans of the likelihood function with<br />

respect to the �È parameters. To estimate how likely the error obta<strong>in</strong>ed on the full dataset is, we generated<br />

�� toy experiments with yields given by the data fit (no Poisson fluctuations). Figure 7-16 shows the<br />

pull distributions for �� and ���. Figure 7-17 shows the error distribution from the ensemble of toy<br />

experiments, with the data results <strong>in</strong>dicated by the arrows.<br />

Figure 7-18 shows distributions of Ñ�Ë and ¡� for events enhanced <strong>in</strong> signal �� and Ã� decays us<strong>in</strong>g<br />

likelihood ratio cuts. The curves represent projections of the fit result scaled by the efficiency of the<br />

additional cuts. Figure 7-19 shows the ¡Ø distribution for ��-selected events, with a looser selection than<br />

the one applied <strong>in</strong> Fig. 7-18. We f<strong>in</strong>d that the background resolution function describes the tails of the ¡Ø<br />

distribution well, and the core is consistent with � decay.<br />

7.9.1 Cross-checks<br />

Table 7-21 summarizes several tests to cross-check the stability of the result. We fit separately the Run 1<br />

and Run 2 datasets and f<strong>in</strong>d the weighted averages are consistent with the results for the entire dataset. We<br />

also fit the � and � tag samples separately, aga<strong>in</strong> with consistent results. To test the stability of the fit<br />

MARCELLA BONA

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!