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)
-
2D0 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
3Experimental 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
4FCNC 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
? -
5D(s)? ??? selection
- Cuts separately optimized for D and Ds
- where
- Isolation
6D??? ????-
26 9 D 6511 DS
- Expected value is 1.77?10?6 from the product b.f.
7Continuum D????-
- ? ? mass window excluded
- ? 1.8 0.4 DS events
8Comparisons
- D0 results
- Predictions
- Other results
- Best limits so far and improved version of
analysis in paper submission stages (not public
yet)
9Bs ????
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
10Analysis 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
11B ?J/?K
Small correction to account for Bd decays
- Normalize to B?J/?(????)K
12Results 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
13Bs?????
- In Standard Model, B(Bs????)10-6
- Analysis is similar to Bs ????
- Look for ??KK?
14Bs????? 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
15Results for Bs?????
- Based on 450pb-1 of data - PRD 74, 031107 (2006)
- Normalization Bs ? J/? ?
- B(Bs ?
J/? ?) -
(9.3 ? 3.3) ? 10-4
16Bs ??(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?
17B??(2S) K
B? ? ???
B??(2S) K
18Bs ??(2S) ? Results
??
?(2S)?
19Coming soon
- Bs ??(2S) ?
- Working on a publication with 1.3fb-1 for c?u??
- Bs??? updated result with 2fb-1
20Conclusions
- Have observed
- Limit lt
0.46 _at_ 90 - Bs ??(2S)?
- From 300pb-1 B(Bs????) lt 3.7?10-7 _at_ 95 CL
- Bs?????