Violation in Mixing

128 Measurement of Branching Fractions for � ¦ � Ã � ¦ decays
number of events / 0.0025 GeV
250
200
150
100
50
ALLCHAN 7332.
37.19 / 34
P1 498.1 12.91
P2 23.11 1.272
0
5.2 5.22 5.24 5.26 5.28 5.3
Mes (GeV)
Figure 5-9. ARGUS fit to the Ñ�Ë distribution in the on-resonance side-band region.
5.4.2 Parameterizations of Ñ�Ë Distributions
The background shape in Ñ�Ë is parameterized by the ARGUS function in Eq. 4.6.2. where we use
ÑÑ�Ü � �� ��� ��Î� 2 and where the parameter � is determined from a fit. A fit to the on-resonance
side-band region after applying the standard selection (see Sec. 4.2.1) gives � � � ¦ � (Fig. 5-9).
A similar fit performed on off-resonance grand side-band region gives � � � ¦ �� and we find � �
� ¦ � in continuum Monte Carlo events (Fig. 5-10). All the values obtained from these samples are
well compatible with each other and with the on-resonance fit. We use the value � � � ¦ � in the rest
of this analysis.
The Ñ�Ë PDF for the signal is parameterized as a Gaussian with mean of �� � ��Î� and width of
���� taken from the � � � � control sample (4.2.2.1).
5.4.3 Fisher Discriminant
The Fisher discriminant has already been defined in Sec. 4.3. For the parameterization of the Fisher variable
in signal events we have used signal Ã Ë � MC, while for the Fisher variable in the background events, we
have used the on-resonance Ñ�Ë side-band (�� �Ñ�Ë � �� � ��Î).
2 This parameter is determined in a mode independent way: see Sec.4.6.2
MARCELLA BONA