# Presentation: 563683

## B Physics at CDFResults and Prospects

- Iván Vila
- Instituto de Física de Cantabria, Spain

- Lake Louise Winter Institute
***Lake Louise, Canada -  15******th****** -22******nd******   February 2003***

## In this talk 

- Introduction
- Cross-section
- Masses
- Lifetimes
- Spectroscopy
- Rare Decays
- CP Violation
- Bs Mixing

- DISCLAIMER: 1001 B and Charm physics analysis at CDF
- 		  Here not at all exhaustive summary

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## B physics at Tevatron

- Large b production cross-section
- (bb) ~ 50b (5kHz @ E32)
- (bX, |y(b)|≤1) ~ 30b            (3000Hz @ E32)
- compare: (bb) ~ 1nb at (4S) (    10Hz @ E34)
- Many  B hadrons states produced:
-  B0, B+, Bs, b, Bc, b
- But... HUGE inelastic cross section ~ 100mb
- A dedicated selective trigger needed vs. B factories inclusive trigger.

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## B Triggers

- Di-lepton -  dilepton sample
- pT(/e)>1.5/4.0 GeV/c
- J/ modes, masses, lifetime, x-section
-  Yield 2x Run I (low Pt threshold, increased acceptance)
- lepton + displaced track - semileptonic sample
-  pT(e/)>4 GeV/c 120 m<d0(Trk)<1mm, pT(Trk)>2 GeV/c
- Semileptonic decays, Lifetimes, flavor tagging.
- B Yields 3x Run I
- Two displaced vertex tracks - hadronic sample
-  pT(Trk)>2 GeV/c, 120 m<d0(Trk)<1mm, S pT>5.5 GeV/c
-  Branching ratios, Bs mixing, ...

- Hadronic mode sensitivity increased about five orders of magnitude !

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## B production – Cross Section

- RunI b cross-section ~ 3x NLO QCD
- theoretical approaches: new physics, Next-to-Leading-log resummations, non perturbative fragmentation function from LEP, new factorization schemes...
- Only top 10% in Pt  of the total       x-section measured
- New measurements to lower *p**T**(B)* :
- Inclusive J/Psi cross section up to PT(J/Psi)=0 (first time hadron collider)
- Bottom Quark Production cross-section

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## B Lifetimes and Masses

- Test of HQET predictions

- Inclusive measurements (J/ X dimuon sample)
- Still statistical limited ~ 138 pb-1

- First measurement of b using a exclusive reconstruc.

- Lifetime measurements using the inclusive semileptonic sample are still under progress (expect results soon)
- Mass fit using fully reconstructed B  J/ X decays

- B0, B+ competitive with PDG, and Bs and b the World’s best measurement

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## Spectroscopy – Exotic States X(3872)

- New narrow state observed first by Belle in            decay modes
- Charmonium state not expected near mass peak.
- D* Dbar deuteron-like molecule ?
- CDF confirms X in 220pb-1
- Preference for M( ) > 500MeV
- 670±90 candidates, sign.~ 12
- Mass scale using (2S) peak

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## Rare decays - Bs,Bd  

- BR(Bs  ) ~ 10-9 in SM (SUSY physics two orders of magnitude enhancement)
- Blind analysis optimized for 300-400 pb-1 (~ 1  0.3 expected bkg)

- Limits at 90% C.L.
- BR(Bs->MuMu) < 5.8 E-7
- BR(Bd->MuMu) < 1.5 E-7

- Bs factor 3 better than best published limit (Run I)
- Bd slightly better than Belle’s at LP03: 1.6 E-7@90%CL
- Still room for improvement:  Acceptance &  bkgs

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## CPV - Two body charmless decays B  h+h-

- 1. extracting the signal

- Time dependent asymmetry Bd    ( angle)  and Bs  KK ( angle)
- Direct CP asymmetry of the self tagging modes Bd  K and Bs  K

- Online hadronic selection
- + B pointing prim. vertex,
- displaced & isolated

- 2. Separation of the components

- dE/dx ~ 1.3 for K/ separation
- Statistical separation is still possible
- Unbinned log-likelihood fit defined including
- Kinematical variables M() and =(1-p1/p2)q1
- dE/dx

| Mode | Yield (65 pb-1) |
| --- | --- |
| B0  K | 14817(stat.)  17(syst) |
| B0    | 3914(stat.)  17(syst) |
| Bs  KK | 9017(stat.)  17(syst) |
| Bs  K | 311(stat.)  17(syst) |

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## First observation Bs  KK 

- First observation Bs  KK

- Direct ACP violation ~ 0

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## Bs mixing – Signal Reconstruction

- Bs mixing unique to CDF requires
- Event yield
- Clean signals (S/B)
- Vertexing resolution
- Tagging effectiveness: D2

-  For semileptonic decays

-  Fully reconstructed decays boost resolution

-  **CDF Golden Channel B****s**** ******** D****s******

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## Bs Mixing - Flavor tagging

- Flavor taggers optimized  on high statistics semileptonic sample
- Unbiased performance in high purity inclusive sample

- CDF Results:
- Same-side (B+)    	D2(2.10.7)%
- Muon tagging       	D2 (0.70.1)%
- JQT, SET 	  	almost there
- OSKT NEW! RunII          	on progress

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## Bs Mixing – Improvements

- Idealistic “Yellow Book” projections
- Detector acceptance and trigger efficiency very improved 2x Bs selection

- Under current conditions (BsDs )
- S = 1600 events/fb-1
- S/B = 2/1
- D2 = 4 % (SLT+SST+JQT)
-  t=67 fs

- Modest improvements
- Adding  Ds  K*K,KsK y Bs  Ds3
- 	S = 1600 events/fb-1  2000 events/fb-1
- L00 innermost silicon layer, event by event beam-line reconstruction
- D2 = 5 %

- t=67 fs  t=50 fs

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## Bs Mixing – Projections

- Short term 500 pb-1 (no improvement up to 2005)
- 2(for ms = 15 ps-1)
- Reach the current indirect limit.
- Cover the Standard Model favored range

- Beyond the SM favored range (conservative improvements up to 2008):
- 5  if ms = 18 ps-1 with 1.8 fb-1
- 5  if m = 24 ps-1 with 3.2 fb-1

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004

## Summary and Conclusions

- After 2003 fall shutdown the Tevatron is performing very well.
- CDF Run II accumulated over 290pb-1 of data (~ 2.5 larger than Run I).
- The new displaced track trigger has been a great success
- CDF is back in the game of producing world class results.
- (Unique Bs,b physics, competitive Bd, Bu physics in same cases)
- Benchmark lifetime and mass analysis probe excellent detector performance
- World best limits Bs and Bd 
- First observation of Bs  KK modes
- CPV in B  hh, CDF major player in this arena.
- Bs mixing:
- Reach current indirect limit  with 500pb-1 (end 2004)
- 5sensitivity over SM preferred range (up to 24 ps-1) in 3fb-1(end 2008)

- I. Vila                   Lake Louise Winter Institute 2004

- Feb 18th  2004