# Presentation: 791908

## Probing the Standard Model Frontier with B Physics at CDF

- Alessandro Cerri

## Synopsis

- The Big Picture
- Why B physics at the TeVatron is a good bet
- Tools of the trade
- CDF: detector and DAQ
- SVT: the CDF key to B physics
- Selected examples
- Hadronic Moments in bcl (Vcb)
- Bs Mixing (Vtd and new physics)
- Perspectives
- Conclusions

**Notes:**
This is the synopsis of my talk: 
I will first highlight what the guiding theme of my discussion will be
I will then justify why and how B physics plays a key role in going beyond the SM
I will devote a small part of my discussion to the tools that make B physics possible at CDF
I will pick some of the results of our experiment that show the important things:
The evolution of our understanding of the detector and of the physics reach
The improvement of the tools needed for probing physics BSM
The current situation in this exploration
I will then move to give you my view of the perspectives on this topic
...and finally conclude

## Qualitative to Quantitative

- Like other areas, CKM physics can now precisely probe the Standard Model

**Notes:**
There have been other extremely successful instances of this process in the recent past. I just make three examples which I find particularly interesting:
Kaon physics has moved from a qualitative (is e’/e!=0) to a quantitative era, ruling out ad-hoc models and reaching precisions better than theory predictions
Astrophysics/cosmology moving from a qualitative to a quantitative approach (hubble constant, the really quantitative X-ray era, omega) here you see a brief history of the determination of H0, which follows some of the most important milestones in this process: the discovery of galaxies, HST, WMAP...
CKM physics [UT vertex vs time] has moved from a ‘qualitative’ assessment of CP violation to an era of precision constraints on the standard model
Transition: This will be my topic of choice in approaching the evolution of physics towards the edge of the SM 

## B physics: precision probe of SM and beyond!

- TeVatron contribution is critical!

**Notes:**
Here is the latest-greatest update of the knowledge on the CP violation parameters within the SM, showing all the constraints from the various measurements.
Nowadays this is dominated by B physics measurements.
Current ellipsoid major axis is along Delta m_s:
Tevatron experiments provide key contribution to this picture.

## The Tevatron as a b factory

- The Tevatron as a b factory

- B factories program extensive and very successful BUT limited to Bu,Bd
- Tevatron experiments can produce all b species: Bu,Bd,Bs,Bc, B**, b, b

- Compare to:
- (4S)  1 nb (only B0, B+)
- Z0 7 nb
- Unfortunately
- pp 100 mb

- b production in pp collisions is so large (~300 Hz @ 1032 cm-2 Hz) that we could not even cope with writing it to tape!

**Notes:**
Where does the key role of Tevatron come from?
Main focus is on complementarity of production: B factories cannot measure Dms
Production rate is also a major advantage
Unfortunately the background is several orders of magnitude larger. This led to the development of new tools for effectively selecting events, we will see later

Transition: what physics can we probe with this kind of environment?

## Path to New Physics

- CKM measurements could hint to new physics through discrepancies with SM predictions. How do we get there?
- Design/improve the “tools of the trade”
- Experimental (detector & techniques)
- Theoretical (phenomenological devices)
- Measure uncharted properties at the boundaries of our knowledge
- Masses
- Lifetimes
- Branching ratios
- Press further ahead and investigate beyond the boundaries:
- Mixing
- CP asymmetries

**Notes:**
Mention loop corrections here for the first time

## CDF and the TeVatron

- Renewed detector & Accelerator chain:
- Higher Luminosity     higher event rate
- Detector changes/improvements:
- DAQ redesign
- Improved performance:
- Detector Coverage
- Tracking Quality
- New Trigger strategies for heavy flavors: displaced vertex trigger

- COT

**Si Detector: L00,SVX II, ISL**

**Notes:**
CDF is a general-purpose detector, sitting in one of the two instrumented points of the TeVatron collider.
In order to cope with the higher luminosity and interaction rates, CDF has been upgraded and at the same time
Its performance has been improved. Nowadays we have more than 1fb-1 collected on tape [plot] with the upgraded detector.
I will not go into the details of the improvement. 
I want only to mention that the upgrade has played a key role in CDF B physics reach, especially in improving the tracking detectors
Performances, and in giving us the ability of selecting events based on high resolution tracking at trigger level with the Silicon Vertex Trigger.
Why, and how is that possible?

## SVT: a specialized B physics triggerrequirements

- SVT: a specialized B physics triggerrequirements

- Good IP resolution
- ASAP (10 sec)
- No Dead Time

- @ earliest L2 where silicon data starts flowing
- Drop stereo info: 2D tracking
- Extensive custom design

**Notes:**
The idea behind this device is that one can in principle reconstruct tracks with silicon information during data taking and use such high resolution information to select events with long
Lived (heavy flavored) particles.
CDF has a 3 level DAQ system, and silicon information is readout in less than 10us, making it available in principle for L2 processing. 
This defines the constraints to the device that makes the success of B physics at CDF:
Good IP resolution
In a timely fashion
With a deadtimeless performance
These constraints led to a design of a device 
sitting at the input of level 2 (where the silicon data starts flowing)
Performing 2D tracking for improved speed
Making extensive usage of customized hardware

## ...and a successful endeavor!

- ...and a successful endeavor!

- SVT is capable of digesting >20000 evts/second to identifying tracks in the silicon

- CDFII has been running it since day -1

- The recipe uses specialized hardware:
- Clustering
-       Find clusters (hits) from detector ‘strips’ at full detector resolution
- Template matching
-       Identify roads: pre-defined track templates with coarser detector bins (superstrips)
- Linearized track fitting
-       Fit tracks, with combinatorial limited to clusters within roads

**Notes:**
The result is nowadays give for granted, even though we are talking about something able to digest several GB/s at 20000 events/second without a complaint!
SVT has been working since day 0 [Halloween night, 5 years ago!] (even before L2 was ready to accept its output)
The secret of the performance lies in a three-tiered structure where we perform 
first the identification of clusters of strips above threshold in the silicon detector
Then resample those clusters at coarser resolution and identify ‘roads’: combinations of these ‘superstrips’ which can correspond to physical tracks
Once this pattern recognition is performed, the combinatorial problem is reduced only to hit combinations sitting within a given road, which is therefore treatable with a linearized fit algorithm
The resulting performance is offline like, as it is demonstrated by the distribution of measured impact parameter with respect to the beamline in this histogram obtained in real-time from the actual SVT hardware.

A device allowing to select on the fly events based on their heavy flavor content opens up a large range of possibilities at an hadron collider. I want to describe now how we explored this physics potential,
moving from the preliminary design of our instruments to their refinement and then focusing on the attractive task of probing the SM boundaries.

## Benchmarks

## What was known about non--produced b (PDG’04)

**Notes:**
This is what the pre-CDFII landscape of our knowledge looked like for some of the b hadrons inaccessible at B factories: few very poorly known branching ratios and masses... a desert more than a well defined landscape!

## Measure: Branching Ratios

- http://www-cdf.fnal.gov/physics/new/bottom/031002.blessed-bs-br/

- http://www-cdf.fnal.gov/physics/new/bottom/030702.blessed-lblcpi-ratio_new/

- http://www-cdf.fnal.gov/physics/new/bottom/050310.blessed-dsd/

- http://www-cdf.fnal.gov/physics/new/bottom/050407.blessed-lbbr/

- http://www-cdf.fnal.gov/physics/new/bottom/050310.blessed-dsd/

- First-time measurement of many Bs and b  Branching Fractions

- Hep-ex/0502044

**Notes:**
With little effort (and integrated luminosity) CDF is able to competitively complement the current knowledge. Many more Branching ratios to come, but this – together with other basic achievements like lifetimes and masses - tells you already that our basic understanding of the system has been thoroughly tested. The basic tools are there for more advanced analyses!

Title & blue comment should make clear that we are exploring new exclusive decays at a level never probed before! (point out explicitely that this is the first time that these exclusive modes have been ‘measured’)

Use statistics as liaison

## Lifetimes: fully reconstructed hadronic modes

- (B+) = **1.661±0.027±0.013 ps **
- (B0) = **1.511±0.023±0.013 ps**
- (Bs) = **1.598±0.097±0.017 ps**

- Testbed for our ability to understand trigger biases
- Large, clean samples with understood backgrounds
- Excellent mass and vertex resolution
- Prerequisite for mixing fits!

**http://www-cdf.fnal.gov/physics/new/bottom/050303.blessed-bhadlife/**

- KK

- Systematics (m)

**Notes:**
Good mass resolution and understanding of the (mostly b) background

## Improving SM Tools

## Closing up on CKM

- 

- 

- 

- B+

- D0

- QCD corrections  uncertainty on the b wave function inside the meson
- This is something that can be constrained experimentally!

**Notes:**
Triangle
point out that the connection between the phenomenology and the quark-physics goes through QCD corrections which need to be kept under control
This is a job for experiments as well, since we can provide constraints on the QCD systematics
(drawing of the ‘dressed’ b->c transition & CKM?)

## Improving phenomenological tools: Hadronic Moments

- No room for everything... I will focus on one example:
- HQET/OPE is a fundamental tool for CKM physics with B mesons. For instance it relates:
- BXul to [bul]  Vub
- BXcl to [bcl]  Vcb
- OPE is “semi-empirical”: parameterizes any prediction in a series expansion of effective operators
- Expectation value of these operators is a “universal” property of the theory which can be assessed with concurrent measurements
- Example: Vcb (±1%exp±2.5%theo)  Hadronic Moments

**Notes:**
The tools we need to build and strengthen are not only our experimental techniques, but also the theoretical/phenomenological tools used to compare theory and experiment: this is especially important in approaching evidences of inadequacy of a model (e.g. the standard model).
As an example I will discuss in this talk one of the most precious phenomenological tools used to relate experimental B physics quantities to the CKM parameters: HQET and OPE

## Moments-ology

-   Hadronic moments: BXcl, recoil mass M(Xc)

-   Leptonic moments: BXcl, lepton E in B rest frame

-   Photonic moments: Photon energy in b  s 

- (CLEO, DELPHI, BABAR)

- (CLEO)

- (CLEO, DELPHI, BABAR, CDFII)

- Many inclusive observables can be written using the same expansion (same non-perturbative parameters).  The spectral moments:

-  Aim: Constrain the unknown non-pert. parameters and reduce |Vcb| uncertainty.
-  With enough measurements: test of underlying assumptions (duality...).

## What is Xc?

- ~25% of semi-leptonic width
-     is poorly known

- Higher mass states: D**

- Semi-leptonic widths (PDG 04):

|  |          Br (%) |
| --- | --- |
| B+  Xc l  |    10.99  0.31 |
| B+  D* l  |      6.04  0.23 |
| B+  D l  |      2.23  0.15 |

- (PDG b/B+/B0 combination, bu subtracted)

- Possible D’D(*) contributions neglected:
-   No BlD’ experimental evidence so far
-   DELPHI limit:
-                    We assume no D’ contribution in our sample

## Analysis Strategy

- Typical mass spectrum M(X0c) (Monte Carlo):

-  D0 and D*0 well-known
-  measure only f**
-  only shape needed

- 1) Measure f**(sH)
- 2) Correct for background,
- acceptances, bias
-  moments of D**
- 3) Add D and D*  M1,M2
- 4) Extract OPE parameters
- (******, ********1****)**

## D+/D*+ Reconstruction

-   D**0      D*+ **-
- 	      D0 *+                  (Br=67.7%)
- 	                K- +              (Br=3.8%)
-                                   K- + - +    (Br=7.5%)
-                                    K- + 0       (Br=13.0%)

- Exclusive reconstruction of D**:

- “D*+”

- B- D**0l-

- PV

- l-

- -  (aka **)

- +

- +

- K-

- D+

-   D**0      D+ **-
- 	      K- + +  (Br=9.2%)

- “D+”

- ~28K e/D Candidates in total!

## Backgrounds

- _Combinatorial background_
- under the D(*) peaks:
-  sideband subtraction

- _Physics background:_
- BD(*)+Ds-, D(s)Xl
-  MC,  subtracted

- _Prompt pions faking ____**:_
-  **fragmentation**
-  **underlying event**
**separate B and primary vertices**
-     (kills also prompt charm)
-  use impact parameters to discriminate
-  model: wrong-sign **+* *-* *combinations

- _Feed-down in signal:_
- D**0 D*+( D+0)-
- irreducible background to
- D**0 D+-.
- subtracted using data:
- shape from D0- in
-  D**0 D*+( D0+)-
- rate:
- 1⁄2 (isospin) x eff. x BR

## Corrected Mass and D** moments

- Procedure:

-  Unbinned procedure using weighted events.
-   Assign negative weights to background samples.
-   Propagate efficiency corrections to weights.
-   Take care of the D+ / D*+ relative normalization.
-    Compute mean and sigma of distribution.

- Results (in paper):

- No Fit !!!

**Notes:**
Don’t go through the weighting
Point out that there is enough data that you don’t have to perform a fit before extraCTING THE MOMENTS	

## Systematic Errors

|  | m1 (GeV2) | m2
(GeV4) | M1
(GeV2) | M2
(GeV4) | 
(GeV) | 1
(GeV2) |
| --- | --- | --- | --- | --- | --- | --- |
| Stat. | 0.16 | 0.69 | 0.038 | 0.26 | 0.078 | 0.057 |
| Syst. | 0.08 | 0.22 | 0.068 | 0.13 | 0.091 | 0.082 |
| Mass resolution | 0.02 | 0.13 | 0.005 | 0.04 | 0.012 | 0.009 |
| Eff. Corr. (data) | 0.03 | 0.13 | 0.006 | 0.05 | 0.014 | 0.011 |
| Eff. Corr. (MC) | 0.06 | 0.05 | 0.016 | 0.03 | 0.017 | 0.006 |
| Bkgd. (scale) | 0.01 | 0.03 | 0.002 | 0.01 | 0.003 | 0.002 |
| Bkgd. (opt. Bias) | 0.02 | 0.10 | 0.004 | 0.03 | 0.006 | 0.006 |
| Physics bkgd. | 0.01 | 0.02 | 0.002 | 0.01 | 0.004 | 0.002 |
| D+ / D*+ BR | 0.01 | 0.02 | 0.002 | 0.01 | 0.004 | 0.002 |
| D+ / D*+ Eff. | 0.02 | 0.03 | 0.004 | 0.01 | 0.005 | 0.002 |
| Semileptonic BRs |  |  | 0.065 | 0.10 | 0.064 | 0.022 |
| 1 |  |  |  |  | 0.041 | 0.069 |
| Ti |  |  |  |  | 0.032 | 0.031 |
| s |  |  |  |  | 0.018 | 0.007 |
| mb, mc |  |  |  |  | 0.001 | 0.008 |
| Choice of pl* cut |  |  |  |  | 0.019 | 0.009 |

## Results & Comparison with other experiments

| Good agreement with HQET  previous determinations.
First measurement at hadron machines: different environment and experimental techniques.
Competitive with other experiments. | Little model dependency. No assumptions on shape or rate of D** components.
Through integration with other experiments and other “moments” we can seriously probe HQET/QHD
 |
| --- | --- |

- Pole mass scheme

**(Correlated uncertainties)**

**(Correlated uncertainties)**

**(Correlated uncertainties)**

**(Correlated uncertainties)**

## Extraction of the HQE Parameters

- Combination of all the experimental measurements of the hadronic moments
- Effective determination of the two OPE operators relevant at order 1/mB () 1/mB2 (1)
- CDF contributes as much as the B factories in this determination!

**Notes:**
Show lambda1 lambda constraint from our measurement and show how that improves our knowledge of HQET

## Bs Mixing

## Working our way on CKM sides

- 

- 

- 

- Vtd  is derived from mixing effects
- QCD uncertainty is factored out in this case resorting to the relative Bs/Bd mixing rate (Vtd/Vts)
- Beyond the SM physics could enter in loops!

**Notes:**
Simpler triangle
We dealt with Vcb, the next logical step is Vtd -> Bd mixing, which suffers from hadronic uncertainties -> xs/xd as a way of going around them
Box diagram with Bd and Bs mixing
Analogy with K mixing: frequency depends on DeltaM like kaons!
Beyond the standard model: the things going around the box are W, but could be replaced by anything that couples to HF, and could change the value of what I expect
Analogy with lep precision measurements where weak radiative corrections were so well under control that they could check for new physics

## B production at the TeVatron

- Production: ggbb
- NO QM coherence, unlike B factories
- Opposite flavor at productionone of the b quarks can be determined to assess the flavor of the other at production
- Fragmentation products have some memory of b flavor as well

**Notes:**
pp->bb how b are produced and how flavor is identified using the ‘other’ b

Unlike B factories mixing here is incoherent (many particles produced betweent he b and the bbar)

Flavor at production is determined using the away B

## Bs Mixing 101

- ms>>md
- Different oscillation regime        Amplitude Scan

- Perform a ‘fourier transform’ rather than fit for frequency

- ms [ps-1]

- 

- B lifetime

- A

**Notes:**
Start from difference in oscillations
Indicate what the lifetime is with a bar ontop of the histogram (show how many oscillations there are per lifetime)
Approach is then doing a fourier transform
Then point out actual formula
Point out that lifetime resolution is a critical factor
Put a picture of how the amplitude plot looks like, next to the time-dependent plot

## Amplitude Scan

**Just an example: Not based on real data!**

- Mixing amplitude fitted for each (fixed) value of m
- On average every m value (except the true m) will be 0
- “sensitivity” defined for the average experiment [mean 0]
- The actual experiment will have statistical fluctuations
- Actual limit for the actual experiment defined by the systematic band centered at the measured asymmetry

**Notes:**
Explain how to read an amplitude scan, using one of the blinded plots

## Bs Mixing Ingredients

- Event yield

- Flavor tagging

- Signal-to-noise

- Proper time resolution

## Flavor Tagging

- Several methods, none is perfect !!!

- Fragmentation
- product

- B meson

- Reconstructed decay

- “Same Side”

## Bs Mixing: tagging performance

- Summer ‘04

- Fall ’05 (mostly re-optimize existing taggers):
- 1.12±0.18     1.55±0.16
- 1.43±0.093  1.55±0.085

- Measured from Bd data!

## Proper time resolution

- Semileptonic modes: momentum uncertainty
- Fully reconstructed: Lxy uncertainty  improve reconstruction

**Notes:**
Change convolution to sum in quadrature

## Bs Mixing: semileptonic

- ms> 6.8 ps-1 @ 95% CL
- Sensitivity: 10.6 ps-1

- BsDsl
- Ds    (4350100 3.1   )
- DsK*K  (175080  0.42 )
- Ds   (157090  0.32)

- Reach at large ms limited by incomplete reconstruction (ct)!

**Summer ‘04**

- Yield     s/b

## Bs Mixing: hadronic

- ms> 0.0 ps-1 @ 95% CL
- Sensitivity: 9.8 ps-1

- BsDs
- Ds    (55040 ~1.8)
- DsK*K  (24040 ~1.7)
- Ds    (11025 ~1.0)
- Using also BsDs [about 1/3 more statistics]

- Low statistics, but promising!

- Yield    s/b

## Combined Bs mixing limit

- ms> 8.6 ps-1 @ 95% CL
- Sensitivity: 13.0 ps-1

- ms> 16.6 ps-1 @ 95% CL
- Sensitivity: 20.0 ps-1

**Competitive in precision with best experiment at large ********m****s**

- More statistics and improvements to come...

**Notes:**
Point out that the WA includes D0
Point out that D0 has a result with a similar sensitivity

## Bs Mixing Perspectives

- Analysis is pretty much defined! We know where we can improve:

- Statistics
- Data (lumin.: 350pb-1600pb-1??)
- New Modes (e.g. BsDs* >2x?)
- D2 :
- Additional taggers (SSK, OSK...)
- Improve existing algorithms
- Proper time resolution
- Refine event-by-event reconstruction
- Optimal usage of kinematics for non-closed modes

- With the March 2006 data sensitivity~SM value

## What happens for large xs?

- Indirect Measurement of ms:
- SM s/s=0.120.06 (Dunietz, Fleischer & Nierste)

## Probing at large ms: /

- Probing at large ms: /

- BsJ/
*B *VV, mixture of CP even/odd separate by angular analysis
- Combine two-lifetime fit + angular s=H-L

- PRL 94, 101803 2005

- few ps-1 in ms !

**Notes:**
Add reference to ferminews (Konstantint got the URA thesis award for this... somebody else made a thesis out of this?)
Be less incisive on our deficiency, move to deltagamma
Point out that D0 uses our polarization in order to fix some of their fit parameters

Point out that KK can integrate this information

## Beyond the SM

- Analyses like this have laid down the path and the tools and techniques for the exploration of the SM boundaries:
- Non SM effects:
- bd ?
- bs
- Rare decays (bs)
- Bs, etc.
- BK
- Bs
- xs

**Notes:**
Check Bd->mu mu compared to the current BaBar results!

## Rare decays

- Exploit the large B production rate
- Measure relative BR (e.g.  to J/K)  to factor out absolute  and luminosity measurements
- SM: BR(Bs) <3.8E-9
- Sensitive to new physics!

- Publ: PRL 93, 032001 2004   Update: Hep-ex/0502044

- PRD 68, 091101 2003

## CP: sss

- bsss transitions are ‘misbehaving’ at B factories
- ...CDF II can look at them too. We started from K:

- hep-ex/0502044

- ...With the advantage of being able to look at Bs too:

**Notes:**
First measurement of this mode (phiphi) add at the end of the slide

Add the phi phi result here, relate them together, have a reference to the psi ks thing

## Perspectives

- Exciting times ahead:
- Most analyses sensitive to BSM physics are statistically limited
- Significant improvements can be made including new modes and techniques
- Bs results will be an important complementary addition to the CKM mapping!

## Conclusions

- We are living an exciting transition era of more and more quantitative results in the CKM sector
- BSM physics could be around the corner, but hard to discern models without direct evidences
- With LHC we will soon jump in the completely uncharted territory!
- Living this constant exploration of new discoveries puts us at the forefront of human knowledge, but this is not news!
- “Modern science did not spring perfect and complete, as Athena from the head of Zeus, from the mind of Galileo and Descartes”

## Slide 46

## Purgatory

## A guiding theme

- Exploring the boundaries of knowledge is a recurrent theme in history
- Geographical explorations exemplify the paradigm:

- Question
- (Why? Where? What? When? Who?)

- Development of tools
- (ships, telescope, microscope...)

- Explore the boundaries of knowledge
- (ships, telescope, microscope)

- Jump in! (the unknown)
- (America, planets, atoms...)

- G. Galilei

**Notes:**
Analogy with geographical explorations: first map the territory coarser, then narrow in
Key ingredients: CuriosityToolsExplorationDiscovery
Our fantasy, when applied to the unknown often generates an incredible zoology!
I want to recall here two great examples of our history: Colombo, who was the pioneer of this process in geographical discoveries, and Galileo who made the transition from observation to measurement, building the foundations of modern science. 
It is only natural for us to find this process of discovery replicated over and over in our activity at the forefront of knowledge: I will use it as a guide in my discussion on approaching the next frontier of particle physics.
Our field is moving towards the edge of the standard model of elementary particles and will soon jump into the unknown sea of new phenomenology [with all its monsters]!

## Hadronic Moments, HQET and Vcb

*F**theory** * evaluated using OPE in HQET: expansion in s and 1/mB  powers:
- O(1/mB)   1 parameter:                      (Bauer et al., PRD 67 (2003) 071301)
- O(1/mB2)  2 more parameters:  1, 2
- O(1/mB3)  6 more parameters:  1, 2, T1-4

- (4S), LEP/SLD, CDF measurements.       Experimental  |Vcb|~1%

- Theory with pert. and non-pert.  corrections.  |Vcb|~2.5%

- Most precise determination of *V**cb* comes from *sl* (“inclusive” determination):

- Constrained from pseudo-scalar/vector B and D mass differences

## How can CDF look at it?

- D**0  D+-  OK
- D**0  D00    Not reconstructed. Half the rate of D+ -
- D**0  D*+-
- D*+  D0+  OK
- D*+  D+0   Not reconstructed. Feed-down to D+ -
- D**0 D*00   Not reconstructed. Half the rate of D*+ -

- Must reconstruct all channels to get all the D** states.
-  However CDF has limited capability for neutrals

-  B0D**-l+ always leads to neutral particles  ignore it
-  B- D**0l- better, use isospin for missing channels:

## How to solve the problem in practice

- Correct for (m**), (D+)/(D*)

- Selection:
- Optimize on MC+WS combinations
- Cross check on *
- ** Background
- Combinatorial
- D’
- BDD
- cc
- ...

- Collect as many modes as possible:
- (K)*
- (K)*
- (K0)*
- K
- Check yields
- Validate MC

- Measure selection bias on m** from:
- MC
- D* candidates
- Rely on MC (& PDG) for:
- (D+)/(D*)
- Unseen modes (Isospin)
- Lepton spectrum acceptance

- Subtract backgrounds
- Use PDG to go m**m**
- Compute <m**2> & <m**4>
- Include D(*)0
- Extract , 1
- Systematics

## ** Selection

- Based on topology:
-  impact parameter significances w.r.t. primary, B and D vertices

- pT > 0.4 GeV
- R < 1.0

- |d0PV/| > 3.0
- |d0BV/| < 2.5

- |d0DV/| > 0.8
- Lxy BD > 500m

- Cuts are optimized using MC and background (WS) data:

- Additional cuts only for D+:

## Raw m** distributions

- Measured in m**, shifted by M(D(*)+), side-band subtracted.

**D****2*********,D****0*******

**Feed-down**

**D****1****,D****1*********,D****2*******

## Efficiency Corrections

- 1) Correct the raw mass for any dependence of reco on M(D**):
-   Possible dependence on the D** species (spin).
-   Monte-Carlo for all D** (Goity-Roberts for non-resonant), cross-checked with pure phase space decays.
- Detector simulation shortcomings cause residual data/MC discrepancy: derive corrections from control samples (D* and D daughters)
- 2) Cut on lepton energy in B rest frame:
-   Theoretical predictions need well-defined pl* cut.
-   We can’t measure pl*, but we can correct our measurement to a given cut:
-     pl* > 700 MeV/c.

## Final Result

- Pole mass scheme

- 1S mass scheme

- (m1,m2)=0.61

- (M1,M2)=0.69

## Systematics

- Input parameters
- D(*)+ Masses, in combining D(*) with D** mM [PDG errors]
- BR (BD+/D*+ mM) [PDG errors]
- Experimental
- Detector resolution [re-smear satellite sample by full resolution: 60MeV]
- Data/MC Efficiency discrepancies [measure Pt and m dependency on control sample, probe different fit models]
- Decay models in MC [full kinematic description vs pure phase space]
- Pl* cut correction [repeat measurement at various Pl* thresholds]
- Backgrounds
- Scale [charge correlation WS/RS from fully reconstructed B: 4%]
- Optimization Bias [repeat optimization procedure on bootstrap copies of the sample]
- Physics background [vary 100%]
- BXc [estimate / yield and kinematic differences using MC]
- Fake leptons [no evidence in WS D+l+, charge-correlated negligible]

## CP: hh modes

- http://www-cdf.fnal.gov/physics/new/bottom/040722.blessed-bhh/

- Good agreement with B factories
- First measurement ever of BsKK

- http://www-cdf.fnal.gov/physics/new/bottom/040624.blessed_Lb_hh_limit/

**Notes:**

Emphasize that one of the most important results to come is the Bs->kk lifetime
See how you measure gamma from this!
Be prepared with a backup on how you measure gamma this way (outstanding issue with fs/fd uncertainty?) 
       [paper from mathias etc from BR , and the standard fleisher method to extract gamma]

Comparison with world average with / without cdf
Add the BaBar results for comparison

Bd modes in good agreement
First ever mesaurement of Bs-> KK
Potentially measure gamma