1. Studies of EPR-type flavor entangled states in Y(4s)->B0B0
Summary:
- We use Time Dependent Asymmetry (TDA) to test alternative
models to QM.
- We provide a fully corrected TDA distribution which can be
directly compared to (a large class of) models.
Models examined in the note:
1) QM
2) Pompili and Selleri "Local Realism" model (LR)
3) Home made Spontaneous & immediate Disentanglement (SD)
4) Possible contamination of QM events by a fraction l of SD
i.e. Data = (1-l)QM + lSD
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2. The models for AQM(Dt)=cos(Dmd Dt)
Pompili and Selleri (Local Realism):
Home made (Spontaneous Decorrelation at time~0):
the non-QM models contain information on the decay
time of the individual B mesons.
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3. Time dependent asymmetry for the 3 models
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4. Experimental study collect events with B mesons decaying with
Opposite Flavor (OF) and Same Flavor (SF)
Measure Dt (from Dz)
Asymmetry function of Dt:
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5. Using D*ln events "B0 side": B0 -> D* l n D* -> D0 + slow pion
D0 -> Kp Kpp0 K3p
"Tag side":
remaining particles to standard BELLE procedure.
Select only the subset with highest purity.
see next presentation
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6. Event selection summary
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7. Background subtraction Wrg flavor correction
see next presentation
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8. Raw time dependent asymmetry1 -1
After event selection
syst
stat
Background subtracted ps
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9. Data deconvolution
Data correction is done by a program based on a Singular
Value Decomposition (SVD) of the deconvolution matrices.
The matrices are constructed from a MC set of events
which are supposed to reproduce detector effects.
Problems:
MC is not perfect. Main problem: reproduction of Dz resolution
(we add an extra smearing of 46 ± 40 mm)
2) Unfolding contains regularization/filtering to get rid of
elements which are statistically non significant, with the
MC shapes used as a priori => can discard Data information
3) We have MC events generated only with QM hypothesis,
given Dmd, B0 lifetime (solution: mix OF and SF sets)
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10. Corrected time dependent asymmetryQM
for QM we use Dmd= hbar/s
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11. Systematic errors Sytematic errors in the time dependent asymmetry can
originate from
1) errors in background subtraction (in the note)
2) intrinsic behaviour of deconvolution procedure (in appendix A)
3) imprecision of the Belle full MC
Point 3): we can data-MC discrepancy in the following
- resolution on Dz (appendix A)
- wrong flavour correction (note)
- observables on which we apply a cut (note and appendix B)
AB 6-Feb-06

12. Systematics: selection, backgrd, wrong tag
fit gives a
B± fraction
3.11±0.22%
cuts (appendix B)
 M(D*)-M(D0)
 cos(q(D*,l))
±1s variation
in SF/OF distrib
w = 1.5±0.5%
±1 %
 ±1s variation
in SF/OF distrib
M(D*)-M(D0)
different sidebands
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13. Other control: B0 lifetime
Plot of Deconvolved(SF) + Deconvolved(OF)
fit: 1.532±0.017 ps
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14. Sensitivity to models Generated: QM (analysis errors not included)
lambda from fit LR SD
chi2/11
lambda generated
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15. Results QM: chi2 = 5 for 11 bins LR: 112 " SD: 330 "
lambda = 0.02±0.05
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16. Using pre-Y(4s) Dmd value 0.484 +- 0.012
chi2 ~9/11 bins
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17. using Dm=0.484 +- 0.12 LR SD chi2=76/11bins chi2=277/11 bins
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