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D0 Results on FCNC charm and rare B decays

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Title: D0 Results on FCNC charm and rare B decays


1
  • D0 Results on FCNC charm and rare B decays
  • Alice Bean for the D0 Collaboration
  • University of Kansas
  • D0 Experiment
  • c ? u??-
  • Bs ? ??-
  • Bs ? ???-
  • Bs ? ? ?(2S)

2
D0 Experiment
Located at Fermilab (near Chicago) in the
Tevatron - proton/antiproton collider at 1.96
TeV center of mass energy Data reported from Run
II sample with Luminosity of over 1 fb-1
Silicon Microstrip Tracker Scintillating Fiber
Tracking inside of 2 Tesla solenoid ? lt
3 Muon triggers for B physics ? lt 2 Good
electron/muon ID
3
Experimental Tools
  • ?Muon identification ? lt 2 with pTgt2 GeV
  • ? Hits in both the Silicon and Fiber tracker
  • Good ?2 for B (D) vertex
  • Collinearity or pointing angle (?D)
  • Decay length significance of B (D) vertex (SD)
  • Isolation variable (ID)
  • Impact parameter of track (i.e. S?)

D ???? analysis
4
FCNC c ? u??-
  • - FCNC decays forbidden at tree level in SM
  • - Some scenarios SUSY R parity violation /
    little Higgs models only see FCNC in up quark
    sector
  • We look for Ds??????-?, D??????-? and
    continuum production of ??- above and below the
    ?

5
D(s)? ??? selection
  • Cuts separately optimized for D and Ds
  • where
  • Isolation

6
D??? ????-
26 9 D 6511 DS
  • Expected value is 1.77?10?6 from the product b.f.

7
Continuum D????-
  • ? ? mass window excluded
  • ? 1.8 0.4 DS events

8
Comparisons
  • D0 results
  • Predictions
  • Other results
  • Best limits so far and improved version of
    analysis in paper submission stages (not public
    yet)

9
Bs ????
Standard Model Expectations B(Bs???) 10-9 In
MSSM, BF is enhanced by 3 orders of
magnitude Results are published in PRL 94, 071802
(2005) Luminosity of 300pb-1 results with
sensitivity study for 700pb-1 Normalize to
B?J/?(????)K
10
Analysis variables
  • Blind Analysis with cut optimization based on MC
    signal with background from data sidebands
  • Final event selection based on
  • pointing angle, isolation, and decay length
    significance

11
B ?J/?K
Small correction to account for Bd decays
  • Normalize to B?J/?(????)K

12
Results for Bs????
  • After selection cuts, Bs????
  • The analysis has not been unblinded for 700pb-1
  • B(Bs????) lt 3.7?10-7 (95 CL) 300pb-1
  • Combined sensitivity 2.3 ?10-7 700pb-1
  • Results for 2fb-1 expected for Moriond

13
Bs?????
  • In Standard Model, B(Bs????)10-6
  • Analysis is similar to Bs ????
  • Look for ??KK?

14
Bs????? Selection
  • Cuts
  • Di-muon trigger
  • Two muons pTgt2.5 GeV/c, ?lt2.0
  • Muons form common sec. vertex ?2lt10, pT(???)gt5
    GeV/c
  • Kaons have pTgt0.7GeV/c, 1.008 lt m? lt1.032
    GeV/c2
  • Opening angle lt0.1 rad
  • Decay Length Significance gt10.3
  • Isolation gt0.72
  • Main Errors
  • B(Bs?J/??) - 35 B(J/????) -
    1.7
  • ?J/?? / ???? - 7.5 of Bs?J/??
    - 13.7
  • MC weighting - 1.1 pre-Geant weight -
    3.5
  • CP odd-even lifetime differences - 8.0

15
Results for Bs?????
  • Based on 450pb-1 of data - PRD 74, 031107 (2006)
  • Normalization Bs ? J/? ?
  • B(Bs ?
    J/? ?)

  • (9.3 ? 3.3) ? 10-4

16
Bs ??(2S) ?
  • Studies provide info on the interplay of strong
    and weak interactions.
  • Do Bs decays agree with 60 of the rate from
    B0/B decays to ?(2S) as compared to ??
  • Results presented here based of 300pb-1 of data
  • Bs ? ?(2S) ?
  • ? ??? ?KK?

17
B??(2S) K
  • ?Use as control channel

B? ? ???
B??(2S) K
18
Bs ??(2S) ? Results
??
?(2S)?
19
Coming soon
  • Bs ??(2S) ?
  • Working on a publication with 1.3fb-1 for c?u??
  • Bs??? updated result with 2fb-1

20
Conclusions
  • Have observed
  • Limit lt
    0.46 _at_ 90
  • Bs ??(2S)?
  • From 300pb-1 B(Bs????) lt 3.7?10-7 _at_ 95 CL
  • Bs?????
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