# Presentation: 296784

## “Charm and Beauty at the Tevatron”

- Jack Cranshaw
*Texas Tech University*
***For the CDF and D0 Collaborations***

**Notes:**
Humility of presenting others results

## Why Do B Physics at the Tevatron?

**Why Do B Physics at the Tevatron?**

- Large Cross Section!
- Produce bottom mesons with all flavor combinations as well as bottom baryons.
- Bc, b, b, ...
- Multipurpose detectors **CDF** and D**0** capable of reconstructing many B final states.
- Experience with a 110 pb-1 of Run I data (1992-1996)

- ECM=1.96 TeV

**Notes:**
Go over sigmas
BUT 10^3 background
Emphasize variety

## CDF and D0 Upgrades

***D0****** ***
** ****Faster readout**
** ****Upgraded muon system.**
** ****New Inner tracking (silicon tracker, fiber tracker) **
** ****Si Track Trigger (displaced vertices)**

***CDF***
** ****Faster readout electronics.**
** ****Extended muon coverage.**
** ****Faster, larger silicon vertex tracking system.**
** ****Displaced vertex trigger (*****SVT*****)**

**Notes:**
Quickly point out main points (vertex, tracking, magnet, calorimetry, muons

Balance the text
San serif fonts
Quick

## Status of Data Taking

- Peak Run II luminosity so far 4.5 X 1031 cm-2 s-1
- Approximately 150 pb-1 on tape with a variety of triggers and detector conditions.
- Goal for Run IIa: 2fb-1

- Results presented here based on ~80 pb-1 (CDF) and ~40 pb-1 (D**0**)

**Notes:**
Note log scale on left plot
5-7 pb-1/week

## B Triggers and data samples

**Displaced track   + lepton (e, ********)**
**1 muon/electron p****T****>4 GeV **
**1 other track p****T****>2 GeV **
**SVT IP>120 mm        **
**M(l-Track) < 5 GeV**
**Collected ~70 pb****-1**
**~ 0.5M B********lX signal**
- Semileptonic modes

**2-Track Trig.**
**2 Tracks with p****T ****> 2 GeV SVT IP > 120 mm p****T1****+p****T2**** > 5.5 GeV**
**Collected ~70 pb****-1****      **
**~ 0.5M**** ****D****0********Kp signal**
- Fully hadronic modes

**DiMuon  (J/********)**
** ****2 central muons**
** ****P****T****(********) > 1.5 GeV   ****      (Run I:  > 2 GeV)**
**Trigger on  J/y********mm**
**Collected ~ 70 pb****-1**
**~ 0.5M J/y********mm signal**
- J/ modes down to low PT(J/)** **(~ 0 GeV)

**- sin 2******
**- Masses, lifetimes  **
**- Quarkonia, rare          decays**

**- High statistics lifetime**
** ****tagging studies, mixing**

** ****Rich program for charm and bottom physics**
** ****B****S ****mixing**
** ****CP asymmetries**
** ****Rare decays**

**New at CDF, Coming to D****0**

**Conventional**

**Notes:**
Most charm results available from 2-track
Will not talk about semileptonic

## The Silicon Vertex Tracker (SVT)

- Read out Silicon detector
- & Reconstruct tracks at 10’s of kHz!

- Silicon Vertex Tracker (SVT)

- =48m

- Includes
- 33m
- beamspot

**The Silicon Vertex Tracker (SVT)**

- Rate reduction:

- O(10-1) for 1 track d0>120 m

- O(10-2) for 2 tracks d0>120 m

## Physics Program

**Stage 1 ( ≤ 200 pb****-1****)**
**Charm physics **
**Cross sections, branching ratios**
**Lifetimes and masses**
**B****s****,  ********b**** properties**
**Stage 2 (200-500 pb****-1****)**
**First B****s**** mixing limit/measurement**
**B****c**** properties**
**CP measurements in the B system.**
**Stage 3 (500+ pb****-1****)**
**CKM angle ******
**********s**** from B****c**** ******** J/********, D****s****D****s**
** ****B****c**** ******** J/******
**B baryon spectroscopy (********b****, ...)**

*** ******Stage 1 discussed ***
***in this talk***

## World Class Charm Program

**Notes:**
Lots of pretty plots
D0 impact parameter plots

## Quarkonium

**Dimuon states easy to trigger on and reconstruct.**
**Understand energy loss corrections.**
**Many B mesons decay to J/******** X.**

**500K**
**events**

**75K **
**events**

**Notes:**
Jpsi for 
  - ref signal (eloss)
  - B final states
Upsilon for confirmation
Chi for em for rare

##  and Bottom Baryons

** ****and Bottom Baryons**

- Can reconstruct many charmed and bottomed baryons: m, , 
-  c, b, b
- Use all three trigger paths, e.g.
-  b  J/
-  b c+c+ 
-  b c+-c+ 

**World’s Largest Sample of ********b****’s.**

**Notes:**
Still working on reconstruction issues

Add Kai’s semileptonic Lb

## Prompt Charm Production

**Prompt Charm Production**

**Run I indicated poor theoretical  understanding of flavor production mechanisms **
**Measure integrated and differential cross section for D****0****, D****±**** D*****±****, D****s****±****.**

- K

| D0 (pT≥5.5) | 13.3±0.2±1.5 b |
| --- | --- |
| D+ (pT≥6) | 4.3±0.1±0.7 b |
| D*+ (pT≥6) | 5.2±0.1±0.8 b |
| Ds+ (pT≥8) | 0.75±0.05±0.22 b |

**Notes:**
Theory curves from Cacciari and Nason (private communication)
Yellow band corresponds to varying the renormalization and factorization scales 0.5,2.0

## J/ Cross Section

**First measurement of this type at hadron collider. **

**J/******** Cross Section**

- , || < 0.6

**Extends to p****T****=0**

**Notes:**
Lower trigger threshold allows us to measure to pt=0
Run quickly over rhs of equation

## b Jet Cross Section at D0

-  Run I b-jet xsec results 2-3 times higher than predictions

- Strategy:
- Measure +jet cross-sectionExtract b-content using PTRel

- Data selection & kinematic cuts

-  pT >6 GeV/c, || <0.8
-  |jet| < 0.6
-  ETcorr>20 GeV
-  0.5 cone jet
-  R(jet,)<0.7
-  3.4 pb-1 of data

**b Jet Cross Section at D****0**

**Notes:**
Mu+jet sigma
Ptrel templates from MC
Fit MC to data for fraction
Fold fraction with mu+jet to get bjet
(Muon PT measured in muon system only)

## b Jet Cross Section

- Data unsmeared
- using ansatz
- function

- Dominant error
- is due to jet
- energy scale

- Uncertainty due to
- b quark mass
- renormalization/
- factorization scale
- pdf’s
- fragmentation functions
- Based on NLO calculations
- and applied to Pythia

- Consistent with Run I result

- (not fully corrected
- for lepton losses and
- branching ratio)

**Notes:**
Ansatz F=a*ET^b*(1-(2/sqrt(s)*ET)^g

## B Meson Masses

**B****+**** ********J/******** K****+**** **
**~ 640 signal events**
**(>1000 events with loose selection)**

**B****0**** ********J/******** K*****0 ****(********K********)**
**~ 220 signal events**
**Normalization mode for sin2******** analysis**

**B****s**** ********J/******** ************KK******
**~75 signal events**
**Golden mode for**
******s**** measurement**

**m=5279.32±0.68±0.94 MeV/c****2**
**PDG:  5279.0 ± 0.5**

**m=5280.30±0.92±0.96 MeV/c****2**
**PDG:  5279.4 ± 0.5**

**m=5365.50±1.29±0.94 MeV/c****2**
**PDG:  5369.6 ± 2.4**

**Notes:**
Current best Bs->Psi,phi sample
D0 has similar numbers

Add PDG reference
Scrunch plots

## The Bs Meson

- In 2002 PDG, 65 pages for Bu±, Bd0 modes/ properties, 3.5 pages for Bs0 modes/ properties.
- Only four measured branching fractions.
- Mass states and mixing similar to Bd. Gives access to |Vts| CKM element.
- Provides means of measuring angles  and  of unitarity triangle, especially when combined with measurements of the Bd.

*********m******s****** and x******s****** = ************m******s******/************s****** ***
***still unmeasured***

***Of Particular Interest***
*** ******B******s****** ************ J/*********
*** ******B******s****** ***************************
***B******s****** ************K*********
***Rare decays, e.g. B******s****** ************ *********

**Notes:**
Mention Fleischer

## Need to understand Bs yield for triggers/physics.
Look at relative yield

Using values for fs/fd and Br(Bd D+ ) from the PDG we measure the BR(BsDs + )

- Need to understand Bs yield for triggers/physics.
- Look at relative yield
- Using values for fs/fd and Br(Bd D+ ) from the PDG we measure the BR(BsDs + )

**B****s**** Yield and Branching Ratio**

**Notes:**
Many modes of interest use 2-track hadronic trigger.
Understand realistic yields relative to Bd in B->Dp.
Second peak from partial B->D*p
Yield measurement, yes; but also BR measurement using  PDG.

## Inclusive B  J/X Lifetime

**Inclusive B ******** J/********X Lifetime**

- **=1.561****0.024****0.074 ps D0 (40 pb****-1****)** **=1.526****0.034****0.035 ps CDF (18 pb****-1****)**
**PDG: ** **= 1.564 **** 0.014**

**B**

**J/******

******B  ****through **********

**Notes:**
B fraction?
Check PDG value. Where from?

Demonstrates no non-gaussian tails on resolution function

## B Meson Lifetimes 

**B Meson Lifetimes**** **

**B****+**** ********J/******** K****+**
**B****0**** ********J/******** K****0***** (K****0***** ******** K****+************)**
**B****s**** ******** J/******** ********  (******** ********K****+****K****-****)**

| (ps) | CDF Preliminary | PDG |
| --- | --- | --- |
| B+ | 1.57  0.07  0.02 | 1.674±0.018 |
| Bd | 1.42  0.09  0.02 | 1.542±0.016 |
| Bs | 1.26  0.20  0.02 | 1.461±0.057 |

**PDG: 1.083±0.017**

***D******0****** results coming soon***

**Notes:**
Mention that D0 also has results. 
Doubles the lumi daq.

PDG numbers
Theory expectations?

## D0 Signal for CP Asymmetry

****

****

**KK**

****

**Other D0**

**SM predicts only small rates   (0.1-1%) of mixing and CP violation in charmed meson decays. **
**Good place to look for non-SM physics**
**Measure relative branching fractions of D****0****(D****0****bar) decays for D****0****’s from D*****+ ********D****0******** decays. **
**Use the sign of the soft pion as a flavor tag to measure A****CP****.**

## CP Violation in D0 Decays

***First Run II CP Asymmetries!***

** ****Relative branching fractions in agreement with previous measurements.**
** ****A****CP ****precision limited by understanding of residual detector asymmetries.**

| A(D0K+K-) | 2.0 ± 1.7 ± 0.6 % | PDG: 0.5 ± 1.6 % |
| --- | --- | --- |
| A(D0) | 3.0 ± 1.9 ± 0.6 % | PDG: 2.1 ± 2.6 % |

**Notes:**
Direct CP pointing at equation
Where f is CP states (pp,KK) relative to non-CP state Kp
D0 from D* decay. No bias since strong production,decay.
Mention relative BR, but not emphasize.
Add CP asymmetries from PDG
Charge asymmetry biggest for absolute.

## Flavor Changing Neutral Currents

**Look for FCNC in the decay D****0********************.**
**SM prediction ~10****-13****.**
**R SUSY effects can raise to ~10****-6****.**
**Normalize to D****0********nts to cancel out various normalizations and reduce detector acceptance effects.**
**Blinded analysis. Optimize cuts on pp sample.**
***Able to push current limit downward by ~2.***

**( PDG 90%CL:  < 4.1 x 10****-6 ****)**

**Notes:**
Efficiency differences p, m
Decay in flight

## D0 Flavor Tagging Status

******: efficiency for a tag = **
**D: Dilution =**

**D****0**** Flavor Tagging Status**

| = 63.0    3.6% | = 8.3    1.9% |
| --- | --- |
| D=15.8    8.3 % | D=44.4    21.1% |
| = 65.8    2.4% | = 8.5      1.6 % |
| D=2.4     4.1%   | D=-3.7    19.2% |
| 2.4   1.7% | 3.3   1.8 % |

- Jet tag

- Muon tag

- Signal
- region

- Sidebands

- D2 for signal

**Tagging power :********D****2 ****   ****Significance of a mixing                                           measurement proportional to ********D****2**

**Notes:**
Quickly mention e and D.
Go through numbers.
Mention that CDF also working on this.

## Conclusions

- Substantially improved trigger and detector.
- Some results already pushing the values in the PDG.
- Masses, lifetimes, branching fractions
- Measurements of Bs, Bc mesons and b-baryons properties available only at Tevatron.
- Extensive charm physics reach using two track trigger.
- Large samples of fully reconstructed B hadrons to hadronic final states.
- Establishing firm basis for exploring CP violation in many areas, especially using the Bs.

**Notes:**
New triggers make unexplored already entered last year.

## Cross Sections and Branching Ratios

- During Run I we measured b inclusive cross sections.
- These were systematically above the NLO predictions (by factor ~2.5).
- Many measurements of cross sections and branching ratios were calculated  with respect to a reference signal to avoid uncertainties on trigger efficiencies and measured luminosity.
- In this sense, the ‘B factories’ provide us with valuable ‘calibrations’ for our reference signals.

## Exclusive B Lifetimes 

**B****+**** ********J/******** K****+**
**B****0**** ********J/******** K****0***** (K****0***** ******** K****+************)**
**B****s**** ******** J/******** ********  (******** ********K****+****K****-****)**

**Simultaneous fitting of M****B****, ct. **
**ct = L****B**** / p****B****x M****B****PDG**

|  |  | Run II Preliminary |
| --- | --- | --- |
| B+ | D0 | 1.761 ± 0.24 (ps) |
| B+ | CDF | 1.57  0.07  0.02 (ps) |
| Bd | CDF | 1.42  0.09  0.02 (ps) |
| Bs | CDF | 1.26  0.2  0.02 (ps) |

**Notes:**
Mention that D0 also has results. Doubles the lumi daq.
Fix taus

## Preparing for sin2

- Can measure sin2 with comparable precision to B factories.
- Use comparison with B factories to check our analysis techniques.
- Working on establishing gold plated mode, BdJ/Ks, reconstruction.

**Notes:**
Masses lifetimes

## CDF Run II Detector

**Tracking**
**Silicon Vertex Detector**
- L00
**Intermediate Silicon**
**Central Outer Tracker**
**Endplug Calorimeter**** **
**Muon systems**
**TOF**

**Notes:**
Number 1 Det up

## D0 Run II Detector

*Build on existing strengths*
- Excellent calorimetry with faster readout
- Upgraded muon system for better -ID
*Add new capabilities*
- Inner tracking (silicon tracker, fiber tracker)  with 2T superconducting solenoid
- Si Track Trigger (displaced vertices)

## Accelerator Upgrades

- Replace Main Ring with Main Injector
- Upgrade Pbar storage
- Tevatron upgrade:
-  major luminosity increase
-  1031  5 x 1031  2 x 1032
- 110pb-1    2fb-1     15fb-1
-  Short interbunch to limit Nint/crossing
-  3.5 s  396 ns  132 ns

-  Run I  Run IIa Run IIb

**Notes:**
132 ns to keep Nint down, but may not be possible.
Unknown if we can operate with large Nint.

## Run II Improvements

**Silicon detectors (SVXII, ISL):****	**
- Double SVX length for full acceptance (SVX II)
- Double sided silicon for 3-D track reconstruction (SVXII)
- More silicon layers & forward silicon (ISL) for standalone tracking
- Secondary vertex trigger at LV2 (20 ms) (SVT)
** ****Central tracker (COT):**
-  Double the number of stereo layers (COT)
- x 6 more sense wires improves occupancy (COT)
** ****Muon system:**
-  Improved coverage: old “holes” fixed and push to || = 1.5 (IMU)
** ****New Plug calorimeter**
-  Add preshower and shower max detector

## Unitarity Angles , 

- Measure/limit  based on Bd 
- Measure  using combination of
- Bd 
- Bs 
- Challenges
- Separation of Bd,s 
- Understanding penguin contributions (using both decays helps)
- In addition there are interference amplitudes due to mixing.
- However ample statistics for precision observation of asymmetry.

***Decays related by d,s interchange***

*Fleischer PLB 459 (1999) 306*

## CDF Run II Trigger System

- Front-end electronics
- Level1 Trigger
-  synchronous, 132 ns
-  42 deep pipeline gives 5.5 ms for L1 decision
-  Accept rate 40-50 kHz
- Level2 Trigger
-  asynchronous
-  Accept rate 300 Hz
- Level3 Trigger (not shown)
-  Farm of 175 PC’s
-  Accept rate 75 Hz

***Detector***

***L1 trigger***

***L2 trigger***

***L3 farm***

***tape***

***Hardware tracking for ***
***p******T****** ************1.5 GeV***

***Muon-track matching***

***Electron-track matching***

***Missing E******T******, sum-E******T***

***Silicon tracking ***

***Jet finding***

***Full event reconstruction***

***Refined electron/photon***
*** ******finding***