# Presentation: 729658

## B-Physics at DØRecent Results & Plans

**Hal Evans****	****(for the D****Ø B group)****	****Columbia U.**

**B-Physics & the D****Ø Detector**
**Recent B-Physics Results**
**Rare Decays**
**Lifetimes**
**Mixing**
**Planning for the Future**

- Tevatron Connection: 24-Jun-05

- H.Evans

## The Data Set

**Analyses Presented Here**
**→ ****~470 pb****-1**

**Coming Soon: 610 pb****-1**

- Tevatron Connection: 24-Jun-05

- H.Evans

## DØ Detector (the cartoon)

**D****Ø Detector (the cartoon)**

**Central Scintillator**

**Forward Mini-drift chamb’s**

**Forward Scint**

**Shielding**

**Tracking: Solenoid(2T), Silicon,FiberTracker,Preshowers**

**New Electronics,Trigger,DAQ**

***Calorimeter***

***Central PDTs***

- Tevatron Connection: 24-Jun-05

- H.Evans

## Tracking

**2 T Magnetic Field**
**track reco to P****T**** = 180 MeV**
**Silicon: 2.7 – 9.5 cm (barrel)**
**6 barrels / 4 layers + disks**
**793K chan’s (most 2-sided)**
**Layer 0 this fall (r ~ 1.7 cm) **
**Fiber Tracker: 20 – 51 cm**
**8 double layers: axial & stereo**
**77K channels**
**Pre-Shower**
**scintillating strips**
**central & forward / axial & stereo**

**Large Acceptance: |********| < 3**

**250 pb****-1**

****** ****~ 60 MeV**

**~10********m**

**~55********m****(P****t**** = 1GeV)**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Muons

****** ****= 2**

**P > 1.5 GeV**

**P > 3.5 GeV**

**Large Coverage****	****|********| < 2**
**High Efficiency**
**High Purity****	****>60% 1-******** @ L1**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Trigger

**Main B-Physics Triggers****Single- and Di-Muon**
**B****s**** Mixing Data Set**
**~67%****	****Di-Muon**
**~25%****	****Single-Muon**
** ****~8%****	****other (********+jet)**

**CAL**

**c/f PS**

**CFT**

**SMT**

**MU**

**FPD**

**L1Cal**

**L1PS**

**L1CTT**

**L1Mu**

**L1FPD**

**L2Cal**

**L2PS**

**L2CTT**

**L2STT**

**L2Mu**

**Global L2**

**Framework**

**Detector**

**Lumi**

**Level 1**

**Level 2**

**2.5 MHz**

**2.5 kHz**

**1 kHz**

**Level 3**

**CalTrk**

**50 Hz**

| Typical Rates (Hz) at L = 41031 cm-2s-1 |  |  |  |
| --- | --- | --- | --- |
| Trigger | L1 | L2 | L3 |
| dimuon | 50 | 15 | 4 |
| single mu | 120 | 100 | 50 |
| Total | 1600 | 800 | 60 |

**L3 limit ~ 50 Hz**
****** ****prescale !**

- Tevatron Connection: 24-Jun-05

- H.Evans

## DØ B-Physics Results

|  Differential X-Section | 160 pb-1 | PRL 94 (2005) |
| --- | --- | --- |
| Bs → Ds1(2536)  v X | 485 pb-1 | preliminary |
| Bc Semileptonic | 210 pb-1 | preliminary |
| B → D** | 250 pb-1 | preliminary |
| B** | 350 pb-1 | preliminary |
| X(3872) | 230 pb-1 | PRL 93 (2004) |
| Ds →   and D- →    | 508 pb-1 | preliminary |
| Bs → + -  | 300 pb-1 | preliminary |
| Bs → + -  | 300 pb-1 | preliminary |
|  | 240 pb-1 | PRL 94 (2005) |
| Bs / | 450 pb-1 | preliminary |
| Bs → Ds  X Lifetime | 400 pb-1 | preliminary |
| B+/B0 Lifetime Ratio | 440 pb-1 | PRL 94 (2005) |
| b → J/  Lifetime | 250 pb-1 | PRL 94 (2005) |
| Bs → J/  Lifetime | 220 pb-1 | PRL 94 (2005) |
| Bs Mixing using Ds()  X and OST | 460 pb-1 | preliminary |
| Bs → Ds(K*K)  X Reconstruction | 200 pb-1 | preliminary |
| Bd Mixing | 250 pb-1 | preliminary |

- Tevatron Connection: 24-Jun-05

- H.Evans

##  B’s Galore !

| Mode | evts / 100pb-1 |
| --- | --- |
| J/  + - | 1.14 M |
| B+  J/ K+ | 1700 |
| Bd  J/ K*0 | 740 |
| Bd  J/ K0S | 40 |
| Bs  J/  | 100 |
| b  J/  | 25 |
| Bc  J/  X | 65 |
| X(3872)  J/ + - | 230 |
| B  D**  v | 210 |
| B**  B  | 150 |
| Bs  Ds1  X | 4 |
| B+  D0 + X | 46.2 K |
| Bd  D*- + X | 10 K |
| Bs  Ds()  X | 2900 |
| Bs  Ds(K*K)  X | 2500 |

**B****s**** ****→ D****s1****(2536) ******** *****v***** X**

**485 pb****-1**

**Signal: 18.5 ****± 5.5 (3.4********)**

**D****s1****+**** ****→ D*****+**** K****S****0**

- Tevatron Connection: 24-Jun-05

- H.Evans

## FCNC Heavy Flavor Decays

**B****s**** ****→ ********+**** ********-**

**B****s**** ****→ ********+**** ********-**** ******

** ****SM BR = (3.4****±1.5)********10****-9**
** ****Enhanced at large tan********   (MSSM ******** tan****6 ********)**
** ****CDF-II: BR < 1.5********10****-7**

** ****SM BR ~ 1.6********10****-6**
** ****Smaller Enhance at large tan******
** ****CDF-I: BR < 6.7********10****-5**

**D****+**** ****→ ********+**** ********-**** ********+**

** ****SM BR ~ 1.0********10****-6****   (dominated by long distance)**
** ****Enhanced in e.g. RPV SUSY**
** ****FOCUS: BR < ****8.8********10****-6**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Bs → +- and +-

**Preselection**
**vertexed ********+********-****  ****P****T******** > 2.5 GeV, |********| < 2.0**
**pair of opp chrg tracks (********)**
**P****T****B**** > 5 GeV**
**Final Selection Discriminants**
**Isolation of ********+********-****(********)**
**Pointing Angle: ********(L****vtx**** , P)**
**L****xy**** Signif: L****xy**** / ********L****xy**
**Normalization Channels**
******+********-**** ****	****B****+**** ****→ J/******** K****+**
******+********-**** ********	****B****s**** ****→ J/******** ******

**B****s****→********+********-**

**B****s****→********+********-******

******+********-**** Events**

**closed**

**300 pb****-1**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Limits

| Channel | Eff wrt Pre-Sel | N(bgrd) | N(data) | BR Limit (95% CL) | SM Pred |
| --- | --- | --- | --- | --- | --- |
| + - | 38.6% | 4.3 ± 1.2 | 4 | 3.7  10-7 | 3.4  10-9 |
| + -  | 52% | 5.1 ± 1.0 | blind | 1.2  10-5 (ave) | 1.6  10-6 |

**B****s**** ****→ ********+**** ********-**** Normalization**

**B****s**** ****→ ********+**** ********-**** ******** Normalization**

**N****Bs**** = 74 ****± 11**

**B****s**** ****→ J/******** ******

- Tevatron Connection: 24-Jun-05

- H.Evans

## Ds+ → +-+ and D+ → +-+

**Select D****(s)**** Signal from ********(********+********-****)******** cand’s w/ Likelihood**
**D Isolation: P****T****(D)/********P****T****(cone)**
**L****xy**** Signif: S****D**** = L****xy****/********L****xy**
**Pointing Angle: ********(L****xy****,P****T****)**
**Signif Ratio: S********(imp-par)/S****D**

**Signal****(D****s****→******** MC)**

**Background****(M****D**** sidebands****)**

**L****sig**** / (L****sig**** + L****bgd****) = d**

**508 pb****-1**

**World Best Limit**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Lifetime Roundup

**Lifetime Roundup**

**D****Ø Lifetime Measurements ****vs ****HFAG World Averages**

**errors scaled x10 for display purposes**

**World Best**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Bs → Ds  v X Lifetime

**B****s**** ****→ D****s****(********) ******** *****v***** X Selection**
**no lifetime biasing cuts**

**Unbinned logL Fit for ******** using**
**signal region**
**wrong- & right-sign sidebands****( to constrain bgrd PDFs)**
**f(signal) from Mass fit**

**300 pb****-1**

**D****- ****→ ******** ********-**
**1300 ± 223**

**Signal Region**
**35955 evts**

**D****s****- ****→ ******** ********-**
**5153 ± 265 ± 450**

**Right Sign****Sideband**

**Wrong Sign****Sideband**

******(Bs) =  1.420 ± 0.043 ± 0.057 ps**

**World Best Measurement ! – HFAG ave now: 1.472 ****± 0.045**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Bs Lifetime Difference

**B****s****  ****→ J/******** ********   (P → V V)**
**CP-Even:****	****S,D waves**
**CP-Odd:****	****P wave**
**relative contributions ******** CP states of B****s**

**Observed Distribution**
**Transversity Angle Fit**
****** ****b/w M eigenstates**
**R******** = |A********(0)|****2**

**Detector effects**

**CP-Odd**

**CP-Even**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Fits to Data

**Data Set: 450 pb****-1**
**9699 candidate events**
**483****±32 B****s**** → J/********(********+********-****) ********(K****+****K****-****)**
**Fit to: M(B****s****), ct****0****, cos******
**Free params**
**f****sig****, ********ave****, R********, ********/********, M(B****s****)**
**+ resolution & bgrd params**

**Fit Results**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Comparing to the SM

**Flavor Specific Decays also constrain ********/******
**Using PDG ********(B****s****→D****s*****lv*****X)**
**Assuming SM ******** CPV ******

- Tevatron Connection: 24-Jun-05

- H.Evans

## Bs Mixing Analysis

**Data Selection**
**B****s**** ****→ D****s****-**** ********+**** *****v***** X****D****s****-**** → ********(K****+****K****-****) ********-**
**no explicit trigger required**
**some ********-dependent cuts****(effects ~cancel in Asym)**
**Opposite Side (Muon) Tagger**
**Q(jet) containing muon**
**P****T****rel**** ******** Q(********)**
**Q(secondary vertex)**
**Eff & Dilution from Data**
****** ****= N****tag****/N****tot**** = 5.1%**
**D = 2******** - 1    = 44.8%****(******** = N****correct****/N****tag****)**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Measure Tagging using Bd and B+

****** ****D****0**** X Sample****(85% B****+**** - 15% B****d****)**

****** ****D*****0**** X Sample****(85% B****d**** - 15% B****+****)**

| u | 0.734 ± 0.015 |  |
| --- | --- | --- |
| d | 0.724 ± 0.021 | use in Bs fits |
| md | 0.558 ± 0.048 ps-1 |  |
| (HFAG | 0.509 ± 0.004 ps-1 | winter 05) |

- Tevatron Connection: 24-Jun-05

- H.Evans

## Bs Results

**460 pb****-1**

**Asym vs VPDL**

**DØ Prelim Result**
**95% CL: ********m****s**** > 5.0 ps****-1****sensitivity: 4.6 ps****-1**

**Expected Limit Comparison**

- Tevatron Connection: 24-Jun-05

- H.Evans

## DØ Upgrades for High Luminosity

**D****Ø Upgrades for High Luminosity**

**Trigger (mainly L1)**
**allows viable trigger list as *****L***** > 2********10****32**
**L3 Bandwidth Upgrade**
**current limit for B-Physics triggers is at L3**
**proposal: add dedicated 50 Hz of output bandwidth**
**Silicon Layer-0**
**integrated radiation dose ******** inner SMT layer dies**
**add new, rad hard Layer-0 at R = 1.7 cm**
**Impact Param: 55****→35 ********m****at 1 GeV**

**we are here**

**2********10****32**** cm****-2****s****-1**

**2.9********10****32**** cm****-2****s****-1**

**~golf ball size !**

**dE/dx using SMT**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Reach in Bs Mixing

**In Review Now (for EPS 05)**
**add K*********K mode**
**improved tagging ****(add electrons + more var’s)**

**Toward 1 fb****-1**

**semileptonic sens ~ 12 ps****-1**** with 1 fb****-1s**

**Further Down the Road**

**cover ~full SM range****(but need to establish hadronic modes)**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Lifetime Futures

**Lifetime Futures**

| Bs Lifetime Projections |  |  |  |  |
| --- | --- | --- | --- | --- |
| Mode | Lumi (fb-1) | Stat (ps) | Syst (ps) | Tot (ps) |
| Ds  X | 0.4 | 0.043 | 0.057 | 0.071 |
|  | 4.0 | 0.013 | 0.03 | 0.034 |
| Ds  | 4.0 | 0.04 | 0.01 | 0.04 |

| / Projections |  |
| --- | --- |
| Lumi (fb-1) | Error on / |
| 0.45 | 0.45 |
| 2 | 0.12 |
| 4 | 0.08 |
| 8 | 0.06 |
| Theory | 0.12 ± 0.05 |

**Assumes: **
** ****Layer-0 + 3-angle Fit for ********/******

**reduction coming soon**

**450 pb****-1**

**D****Ø ********fs**** & ********/******

- Tevatron Connection: 24-Jun-05

- H.Evans

## More Crystal Ball Gazing

**Most D****Ø B-Physics Results are Statistics Limited**
**Rare Decays**
**reoptimize selections, F-B Asym’s, K****S********+********-****, K*************+********-****, ...**
**broaden charm FCNC analysis**
******/******
**3-angle fits, Separate Lifetimes for CP-state (********, D****s****(*)****D****s****(*)****)**
**Integrated CP asym in semileptonic, ********s****, ...**
**B****s**** Mixing**
**more modes: *****K*************K*****,3********,K****s****K + B****s**** → D****s**** ******
**better tagging: *****electrons, more variables***
**event-by-event likelihood fits**
**(some) Others**
**B**********,**** ****D**, D****s1****: move from observation → measure properties**
**J/******** & ******** Polarization and b cross-section**
**B****c**** semileptonic and hadronic decays**
**make more use of neutral particles (********, ********0****, ********c****→J/******** ******** ...)**
**more decay modes**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Conclusions (Beginnings ?)

**D****Ø Physics Program is Hitting its Stride**
**detector well-suited to many measurements**
**Several World Best Results**
**D****+**** → ********+**** ********-**** ********+**** ; B****s**** Lifetime**
**Interesting New Results Just Around the Corner**
**improved ********m****s****, rare decays, ... for EPS 05**
**DØ Upgrades for High Lumi ******** Improve Performance**
**trigger, layer-0, L3 bandwidth upgrade**

**Stay Tuned !**

- Tevatron Connection: 24-Jun-05

- H.Evans

## Backup Slides

- Tevatron Connection: 24-Jun-05

- H.Evans

## Low PT Tracking

- Tevatron Connection: 24-Jun-05

- H.Evans

## B → + - () Final Discriminants

**B****s**** ****→ ********+**** ********-**

**B****s**** ****→ ********+**** ********-**** ******

- Tevatron Connection: 24-Jun-05

- H.Evans

## Bs Mixing Details

- Tevatron Connection: 24-Jun-05

- H.Evans