# Presentation: 943215

## Current and Anticipated Results in Bottom and Charm Physics from the Tevatron

**Jonathan Lewis**
**Fermilab**
**Aspen Winter Conference**
**January 2003**

## B Program: Complement to e+e- Factories

**B****s**
**Flavor oscillations**
**CP Violation**
**Fits combining B****s****→h****+****h****-**** and B****d****→h****+****h****-**
**New physics in           *****B******s******0 ******→ J/ψ φ***
**Mass, lifetime**
**B****c**
**Mass, lifetime, production, resonances(?)**

**b Baryons: Λ****b****, Ξ****b**** **
**Mass, lifetime**
**CP Violation**
**Λ****b**** → pπ****-**** vs. Λ****b**** → pπ****+**** **
**B and D rare decays**
**No tagging penalty!**
**QCD**
**B and D production in pp collisions**
**Quarkonium**

**Today’s Talk:  Where we are on road to the Physics**
**Results from Summer 2002**

## Run 1: The Foundation

**B triggers required leptons in the final state trigger**
**Semileptonic channel highlights:**
**B****0****B****0**** Mixing, Production, Lifetimes**

*******m *****= 0.47 ± 0.07 ps****-1**

## Run 1: b J

**Run 1: *****b************ J*********

**Rich and pure channel**
**Highlights: Lifetimes, production, B****c****, first hint of CP **

***B******0************J************K******S******0***

- CDF Run 1

**Yesterday’s sensation is   today’s calibration**

## Run 2 Revolution

**Higher Energy**
**Higher Luminosity**
**Higher Bandwidth**
**Precision Tracking**
**CDF:  New 96-layer drift chamber, 7-layer silicon barrel**
**D0:  2T solenoidal field, 8-layer fiber tracker, silicon barrel and forward disks**
**CDF:  Time-of-flight detector for Kaon ID**
**Displaced Track Triggers for all-hadronic channels**
**What was offline analysis has moved to Level 2 trigger**

## B Physics for Dummies: The 3 R’s

**Rate**
**Cross section**
**Luminosity**
**Trigger**
**Recognition**
**Tagging**
**Reconstruction**
**Extract the signal**
**Minimize the background**

## R #1

**Rate**

## Cross Section

**B physics enabled by large cross section**
*******b*****)~10********b for p****T****>5 GeV, |η|<1**
**~1000 B per second at design luminosity**
**Compare to ~10 B per second at ****Υ****(4S) factories**
**Run 1 total cross section factor ~2 above NLO predictions**
- **s=1800 GeV**
**Effect seen over many channels**
**Energy dependence (630 vs. 1800 GeV) agrees with QCD**

## Theoretical Improvements

**Recent work on the non-perturbative physics**

**Fragmentation functions from NRQCD-inspired fits to LEP data   (names)**

**Resummation of next-to-leading logs and retuning of Petersen fragmentation (********=0.002)**

**Looking forward to marriage of matrix-element and parton-shower Monte Carlos**

**Kniehl, Kramer hep-ph/9901348**

**Cacciari, Nason hep-ph/0204025**

## Cross Section: Run 2

**First D0 measurement**
**Muon + Jet**
- **s=1960 GeV**
***b***** content from *****P******T,rel***
**Lepton momentum                                                                             perpendicular to jet direction**
**Expectations for Run 2**
**Precision tests of perturbative region *****(p******T******2******»m******b******2******) *****with large data samples**
**Detailed exploration of non-perturbative region**
***d**********/dp******T ******(b ************J**********) *****down to  *****p******T******(b)*****=0**

## Luminosity

**Tevatron performance thus far below expectations**
**Getting better**
**Record luminosity: 3.6×10****31****cm****-2****s****-1**
**Best week: 7pb****-1**

**CDF:**
**80 pb****-1**** good runs**
**Excludes studies, commissioning**
**65 pb****-1**** with silicon**
**Typical efficiency for December ~80%**

- Start of CDF
- physics data

## Trigger

**Electrons: E****T****,P****T****>2 GeV**
**Muons: P****T****>1.5 GeV**
**Tracks: P****T****>1.5 GeV**
**Displaced tracks**
**Typically require d****0****>100********m, P****T****>2 GeV**
**CDF SVT resolution ~50********m**
**Includes 30********m rms beam width**
**Differences:**
**CDF pipelined Level 1 allows hadronic B decay trigger**
**D0 has |********|<2 low-p****T**** lepton coverage**

## Hadronic Trigger

**Nominal cuts**
**p****T****> 2 GeV**
**p****T1****+p****T2****>5.5 GeV**
**Opposite Charge**
**Opening Angle**
**2o<********<90o for *****b************c***
**20o<********<135o for ******
**d****0****>100********m**

**Loose cuts (*****b************c *****only*****)***
**p****T****> 2 GeV**
**2o<********<90o**** **
**d****0****>100********m**
**Automatically updating prescale**

## R #2

**Recognition**
**(Tagging)**

## What’s new (and old)

**What’s new (and old)**

**Tagging plans follow from CDF Run 1 results**
**Leptons and jet-charge with greater coverage**
**Same-side tag**
**New Element: Time-of-flight for CDF**
**ID Kaons for P****T ****< 1.6 GeV**
**120 ps resolution**

***φ →K******+******K******-***

## Expected Tagging Performance

**Both Experiments relying on forward tracking and large lepton coverage**

## R #3

**Reconstruction**
**(and results!)**

## Physics Goals With Two Leptons

**CPV in *****B******0 ******→************J/ψ K******S******0***** **
**Yesterday’s sensation is today’s calibration**
**Anomalous CPV in *****B******s******0 ******→ J/ψ φ***
** *****B******0 ******→μμK******(*********
***Λ******b******→J/ψ Λ*****:  Lifetime, production, CPV, etc.**
***B******c****** → J/ψ ***π, ***J/ψ lν***
**Quarkonium production**

## D0 on the Road to Physics

- Muon stand alone system

- Muon plus central tracking

**Good Resolution from new tracker**
***J/ψ → μ******+******μ******-***

## D0 Tracking: Neutral Vees

***K******S******0****** → π******+****** π******-***

***Λ******0***** *****→ p***π

## D0: First Exclusive B Decays

**~5pb****-1****  **
**Sample of 3000 J/*****ψ***
**Outer muon trigger**
**p****T****(μ) > 2 GeV**
**p****T****(K) > 0.5 GeV**
**p****T****(B) > 10 GeV**
**Vertex fit χ****2 ****>10**
**L****xy ****>120 μm**

***B******+ ******→************J/ψ K******+***

## D0: First Physics

**Inclusive b *****→************J/ψX *****Lifetime**
**416 ± 30 signal events**
**2184 ± 47 prompt J/********’s**
******(B) = 492 ± 37 ********m (stat. error only)**
**Compare to PDG: ********(B) = 469 ********m**

***J/ψ *****Cross Section**
**5pb****-1**
**Large rapidity coverage**

## CDF Results: B Meson Masses

**18 pb****-1****, incomplete silicon coverage**
**B****s**** uncertainties already close to Run 1**
**Systematics will be greatly reduced with more data and recent track reconstruction improvements**

***B******+****** → J/ψ K******+***
**5280.6 ±1.7 ±1.1**

***B******0****** → J/ψ K************0***
**5279.8 ±1.9 ±1.4**

***B******s******0****** → J/ψ ******Φ***
**5360.3 ±3.8 ± ****2.9**

**2.1**

## CDF Results: B+ → J/ψ K+ Lifetime 

**18 pb****-1**
**Incomplete Silicon Coverage**
**154 ± 15 Events**
**τ****+****=** **1.49 ± 0.14 (*****stat.*****) ± 0.04 (*****sys.*****) **
**Compare**
**Run 1: 1.68 ± 0.07 ± 0.02 **
**PDG: 1.674 ± 0.018  **

**Expectation:**
**Systematics to be greatly reduced with more data **

## All Hadronic Modes: b→c 

**Primary goal: B****s****-B****s**** favor oscillations **
**a.k.a. Mixing**
**Measure frequency Δm****s**** **
***Δm******s ******/Δm******d*****  yields |*****V******ts*****/*****V******td*****|                                                  up to 5% theoretical                                                              uncertainty**
**Important constraint                                                              on CKM**
**Much more physics along the way and beyond**
**Masses**
**Lifetimes**
**Other CP violation studies**

## Before b comes c

**Hadronic trigger yields large charm samples**
**Both direct and from b decays**
**Significant measurements at hand quickly for charm production and decay properties**
**D****+****-D****s****+**** Mass Splitting**
**Decay mode:  *****φ***π*** , φ →K******+******K******-***
**Δm*****= *****99.28****±0.43±0.27**** ****MeV**
**PDG: ****99.2****±0.5 MeV**
**Systematics dominated by                                                   fit model and selections **
**Can be reduced with                                               more data**

## D0 →h+h- Decays

**Measure Cabibbo-suppressed branching ratios**
**Requires detailed modelling of detector performance**
**No particle ID**
**Account for both hypotheses for *****K****π ***mode**
**10 pb****-1**** sample**
**Systematics dominated by background and acceptance models**

***K******-******π******+***

***π******+******π******-***

***K******+******K******-***

***K******-******π******+******π******0***

## Branching Ratio Results

**Γ(*****D→KK*****)/ Γ(*****D→Kπ*****)        = (11.17±0.48±0.98)%**
**PDG: (10.83±0.27)%**

**Γ(*****D→ ππ*****)/ Γ(*****D→ Kπ*****)      = (3.37±0.20±0.16)%**
**PDG:  (3.76±0.17)%**

## Charm Production

**Displaced track trigger sensitive to long lived D mesons**
**Prompt production much greater than from B**
**Can differentiate based on lifetime and impact parameter (d****0****)**

**Efficiency sculpted by trigger cuts**

**Significant **
**impact**
**parameter**

_**Prompt D**_

**Long apparent **
**lifetime**

_**D from B**_

** ****Excluded **

**OK **

## Prompt Charm Fraction

**Prompt fraction from d0 distribution**
**Resolution function from simulation**
**Check in K****S**** → ππ sample**

**B fraction in several D meson channels**
**D****0********K********            ****16-24 % **
**D*************D****0****          ****11-20 %**
**D************K********         ****11-17 %**
**D****s************             ****32-40 %**

## Charmless B Decays

**Extract CP violation from multiple modes**
***B******d******→ππ***
***B******d******→Kπ***
***B******s******→Kπ***
***B******s******→KK***
**Separate Penguin and Tree amplitudes**

**First signal**

*b*

*u*

*d*

*d*

*u*

*b*

*d*

*d*

*d*

*d*

*u*

*u*

*g*

**3:1 Signal-to-noise**
**Rates understood**
**Consistent with expectations after correction for acceptance**

## Sensitivity for γ 

**Separate modes on a statistical basis using mass shapes and dE/dx**
**Sensitivity depends on strong-interaction phase between tree and penguin processes**
**For 2 fb****-1**** expect δγ~5-10°**

***B******d******→ππ***
***B******d******→Kπ***
***B******s******→Kπ***
***B******s******→KK***

## First All-Hadronic Decays
B- →D0π-, D0 →K-π+

**B****-**** →D****0****π****-****, D****0 ****→K****-****π****+**

- Excluded

**B****s**** Mixing**

**	**

**S:N**
**1:2**
**1:1**
**2:1**

**Mixing 5σ Discovery Sensitivity**

**Event Yield**

**56±12**
**Events**

## Outlook

**CDF **
**4 out-of 5 majority logic for SVT tested this month**
**Expect ~50% efficiency improvement**
**Hoping to run DAQ at higher rates and increase cross section of B events to tape**
**Level 1: 12 kHz → 25 kHz **
**D0**
**Track trigger commissioning complete this winter**
**Fiber and silicon**
**Hoping to improve trigger bandwidth**
**Level 1: now 1 kHz, want 4 kHz**
**Tevatron**
**100 pb****-1**** more by summer**

## Conclusions

**CDF and D0 detectors and reconstruction performing well**
**First B signals seen**
**Lots of work to do**
**Exciting results just around the corner**