# Presentation: 769828

## BTeV:  Overview, Status,        and Prospects

- Rob Kutschke
- Fermilab
- June 21, 2002

- Presented at Beauty-2002, Santiago de Compostela, Galicia, Spain, June 17-21, 2002

- BTeV-doc 762

## What is BTeV?

- At the Tevatron p-p collider, at Fermilab:
- Forward spectrometer.
- Beauty and charm physics:
- Precision measurements.
- Exhaustive search for new physics.
- BTeV is a part of broad program to address fundamental questions in flavor physics.
- Details at: _[http://www-](http://www-btev.fnal.gov/)__[btev](http://www-btev.fnal.gov/)__[.](http://www-btev.fnal.gov/)__[fnal](http://www-btev.fnal.gov/)__[.](http://www-btev.fnal.gov/)__[gov](http://www-btev.fnal.gov/)_
- 4 talks at Beauty02: Kutschke(2), Butler, Newsom.

- Rob Kutschke, Fermilab

- June 21, 2002

## Fundamental Questions in Flavor Physics

- Why families? Why 3?
- Quark mixing angles:  Are they explained by Standard Model (SM)?  Arise from new physics?
- Mass heirarchy:  Why?  Related to mixing angles?
- Is CPT violated?  If so, what physics is behind it?
- Matter/anti-matter asymmetry of the universe: What interactions were involved?
- Quarks vs leptons:  What are the similarities and differences in mass heirarchies and mixing angles?

- Rob Kutschke, Fermilab

- June 21, 2002

## Fundamental Questions in Flavor Physics ...

- These are interesting, compelling, questions which we must answer.
- The program to answer these questions involves present and future experiments in K, D, B, and neutrino physics and in astrophysics.
- BTeV is a crucial part of this program.

- Rob Kutschke, Fermilab

- June 21, 2002

## Physics Goals

- Measure: CP violation in B(uds) , Bs mixing, rare b decay rates,  CP violation and rare decays in the charm sector.
*J. Ellis:** **“My personal interest in CP violation is driven by the search for physics beyond the Standard Model...”*
- We feel that way about all of the BTeV Physics program.
- Look for rare/forbidden decays discover new physics.
- Make an exhaustive search for physics beyond SM and to precisely measure SM parameters.
- Test for inconsistencies in the Standard Model: If found go beyond the SM and elucidate the new physics.

- Rob Kutschke, Fermilab

- June 21, 2002

## A Brief History of BTeV

- January 1999: R&D program approved by lab.
- June 2000: Stage I approval from lab.
- Two arm spectrometer.
- Fall 2001:  funding situation deteriorated.
- Lab asked for a proposal for a descoped detector.
- IR to reuse components from completed CDF/D0.
- May 2002: Stage I approval for descoped detector.
- Instrument only one arm, at least initially.
- PAC recommended  lab explore other IR solutions.
- Offline computed to be supplied via universities (grid).
- Cost reduced about $70M to about $110M.

- Rob Kutschke, Fermilab

- June 21, 2002

## Peering into the Future

- Fall 2002: Fermilab internal cost/schedule review.
- Fall 2002: “P5 type” DOE review.
- Key to obtaining large scale funding.
- Spring 2003: Lehman baseline review.
- FY 2004-2008: Construction funding.
- Install test components early to get real experience.
- Exploring staged installation to get some components in early and  to allow early commissioning.
- 2008: Start of physics running.

- Rob Kutschke, Fermilab

- June 21, 2002

## p

- Rob Kutschke, Fermilab

- June 21, 2002

## The “One Arm” Configuration

- The full vertex detector:
- Covers the full length of IR.
- Level 1 trigger: finds tracks in both z hemispheres to ensure the best primary vertex.
- 1 each:  fwd tracking, RICH, EMCal,   systems.
- The steel for the muon toroid on the                   un-instrumented side:
- Shielding; support the compensating dipole; keep floor loading constant in case we instrument the other arm.
- We retain the full trigger and DA bandwidth.
- Original estimate was conservative.
- See discussion of offline computing ...

- Rob Kutschke, Fermilab

- June 21, 2002

## p

- Toroids

-  Production: bb pairs.

-  Both b hadrons go into one arm.

-  Retain 100% of trigger/DAQ bandwidth

- Rob Kutschke, Fermilab

- June 21, 2002

- Magnet on the IR
- Allows momentum measurement in the trigger.
- Precision vertex detector
- Planar pixel arrays.
- Vertex trigger at Level 1.
- Can trigger on final states with only hadrons.
- PbWO4 Calorimeter
-   and 0 reconstruction.

- Strong Particle ID
- Ring Imaging Cerenkov (RICH) detector.
- Hadron and lepton ID!
- Background rejection.
- Flavor tagging.
- Excellent muon ID system
- Redundant triggering of final states with muons.
- Fast, high capacity DAQ.
- Can record a significant fraction of all B decays.

- Key Design Features of BTeV

- Rob Kutschke, Fermilab

- June 21, 2002

## Design Improvement Since Proposal

- RICH requires two radiators to cover full momentum range: Original: C4F10 aerogel.
- Further study showed that aerogel will not work well enough: too few photons; lost in gas rings.
- Replaced aerogel with liquid C5F12 radiator.
- Gives significant ID power at low momentum.
- RICH has significant power to ID e and :
- We now include this in our reach estimates.
- See my talk at this workshop on Thur. afternoon:
- BTeV: Lepton, Hadron and Photon ID

- Rob Kutschke, Fermilab

- June 21, 2002

## Nominal Tevatron Parameters

- Physics reach estimates are quoted for one Snowmass year (107 s) of running at these parameters.
- Exception: using B0  is two years.

| Parameter  | Value |
| --- | --- |
| Center of Mass Energy | 2 TeV |
| Peak Instantaneous Luminosity | 21032 cm-2 s-1 |
| Yearly Integrated Luminosity | 2 fb-1/year |
| Bunch spacing | 132 ns |
| Luminous region (x,y,z) | (0.003, 0.003, 30.) cm |

- Rob Kutschke, Fermilab

- June 21, 2002

## Flavor Tagging

-    efficiency
- D  Dilution  (Nright-Nwrong)/(Nright+Nwrong)
- Effective tagging efficiency  D2
- Recent extensive study uses:
- Opposite side K± and leptons.
- Opposite side Jet Charge.
- Same side ± (for Bo) or K± for (Bs).
- Poll methods in order of decreasing dilution.
- Conclusion: D2 (Bo) = 0.10, D2 (Bs) = 0.13, difference due to same side tagging.

- Rob Kutschke, Fermilab

- June 21, 2002

## CP Violation CKM Physics andall That

- Rob Kutschke, Fermilab

- June 21, 2002

## Formulation of CKM Matrix

- Good 3 in real part & 5 in imaginary part.
- We know =0.22, A~0.8; constraints on  & 

-   d                       s                           b

- u

- c

- t

- Rob Kutschke, Fermilab

- June 21, 2002

## The 6 CKM Unitarity Triangles

-  &  probably large,  ~0.03,   smaller

- 

- Rob Kutschke, Fermilab

- June 21, 2002

## Measuring 

- sin(2) has already been shown to be non-zero.
- First hints CDF.  Best measurements BaBar/Belle.
- We presume that sin(2) will be well measured before BTeV starts running.
- BTeV should still be able to improve the measurement.
- Sensitivity sin(2) using BoJ/ Ks only in one year of running : ± 0.017.

- Rob Kutschke, Fermilab

- June 21, 2002

## Removing Ambiguities from 

- Bo  Ko, Ko
- Exploits K0S/K0L interference.
- Equal amplitudes to 
- Low yield:
- 1/100 of Ks+-.
- 1700/year (untagged)
- Can determine sign of  with O(100) low background, tagged events.
- Sensitivity improves for smalle sin(2).

- tK integrated over tB

- Decay Rate

- For sin(2)=0.7

- Rob Kutschke, Fermilab

- June 21, 2002

## Measuring 

- B0 :
- Sensitivity to ACP in one year:  ±0.030
- But penguin pollution!
- Need and  to unpollute. Tough to do!
- B0  
- Dalitz plot analysis (Snyder and Quinn ).
- (next page)

- Sensitive to both sin(2) and cos(2).

- Rob Kutschke, Fermilab

- June 21, 2002

## Mini MC Study of B0  

| (gen) |  Rres |   Rnon | (recon) |  |
| --- | --- | --- | --- | --- |
|   77.3o |   0.2 |   0.2 |    77.2o |   1.6o |
|   77.3o |   0.4 |     0 |    77.1o |   1.8o |
|   93.0o |   0.2 |    0.2 |    93.3o |   1.9o |
|   93.0o |   0.4 |     0 |    93.3o |   2.1o |
| 111.0o |   0.2 |    0.2 |  111.7o |   3.9o |
| 111.0o |   0.4 |    0.2 |  110.4o |   4.3o |

- Dalitz plot density:
- Synder Quinn matrix element.
- Incoherent BG:  S:BG = 4:1.
- Non-resonant (flat).
- Resonant in .
- Acceptance and smearing parameterized from Geant based study.
- Results for trials of 1000 signal events + BG.
- Sensitivity (two years) < 4o.

- Rob Kutschke, Fermilab

- June 21, 2002

## Four Ways of Measuring 

- Time dependent flavor tagged analysis of BsDsK
- Sensitivity in one year: ±8o
- Rate difference between B-DoK- & B+DoK+.
- Sensitivity in one year: ±13o
- Rate measurements in Ko and K(Fleisher-Mannel)or rates in Ko & asymmetry in K(Neubert et al)
- Sensitivity in one year: ±4o  + Theory uncertainties.
- Use U spin symmetry ds: measure time dependent asymmetries in both Bo& BsKK(Fleischer)

- Model
- independent

- Rob Kutschke, Fermilab

- June 21, 2002

## Measuring 

- BsJ/and BsJ/
-   l+l-
- We now use both electrons and muons.
- This measurement is possible because of the excellent photon and 0 detection provided by the PbWO4 calorimeter.
- Excellent S/B: 15:1 for  and 30:1 for .
- Sensitivity for one years running: ±0.024.
- Will take several years to resolve expected: 

- Rob Kutschke, Fermilab

- June 21, 2002

## xs Reach

- If xs is less than about 70, BTeV will be able to measure it in about 1 year.
- If it is less than about 80, BTeV will be able to measure it in about 3.2 years.

- Rob Kutschke, Fermilab

- June 21, 2002

## Physics Beyond the Standard Model

- New Physics (NP) effects can be subtle:
- More than just:   180o.
- Suppose there is NP in B0 mixing:
- If we measure  and  via mixing mediated modes, J/K0S and , we may measure:
-  
-  
- And measure  via a non mixing method.
-   = 180o
- The triangle closure test misses this sort of NP.
- We need to be careful when we do this!

- Rob Kutschke, Fermilab

- June 21, 2002

## Generic Tests for New Physics

- Specific decays, non-specific models
*B****K*+- & *B****K**+-: can observe NP in distribution of M(+-) and Dalitz plot is sensitive to subtle interference effects.   See hep-ph/9408382.
- Check for inconsistencies in SM without reference to a particular model.

| Reaction | B(10-6) | Yield/year | S/B |
| --- | --- | --- | --- |
| BK* | 1.5 | 2530 | 11 |
| BK | 0.4 | 1470 | 3.2 |
| bs  | 5.7 | 4140 | 0.13 |

- Rob Kutschke, Fermilab

- June 21, 2002

## Critical Checks using 

- Silva & Wolfenstein (hep-ph/9610208), (Aleksan, Kayser & London):
- Measure using BsJ/  
- Can also use J/but need a complicated angular analysis.
- The critical check is:
- Very sensitive since 0.2205±0.0018
- Since ~ 0.03, need lots of data.
- Sensitivity to  for one years running: ±0.024.

- Rob Kutschke, Fermilab

- June 21, 2002

## Survey of New Physics Sensitivities

- See the BTeV “Proposal Update” for a discussion of how many NP ideas can be tested in B decay.
- MSSM and othe SUSY variants
- Left-Right Symmetric models
- 2 Higgs doublet models
- Extra d type single quarks.
- FCNC couplings of the Z.
- Non-commutative geometries
- Mixing with a 4th generation.
- Extra dimensions

- Rob Kutschke, Fermilab

- June 21, 2002

## Tests for New Physics (Nir, hep-ph/9911321)

- Suppose NP in Bo mixing, D , Bo decay, A, Do mixing, K

| Model |  dN/10-25 | D |    A | asyDK |
| --- | --- | --- | --- | --- |
|   SM |   10-6 |     0 |    0 |     0 |
| Approximate 
Universality |   10-2 |  (0.2)    |  (1) |     0 |
| Alignment |   10-3 |  (0.2)    |  (1) |    (1) |
| Heavy squarks |   ~10-1 |   (1)    |  (1) |  (10-2) |
| Approx. CP |   ~10-1 |     -  |    0  |  (10-3) |

- Specific pattern in each model ways of distinguishing models.

- Rob Kutschke, Fermilab

- June 21, 2002

## Summary of New Physics

- Using b and c decays mediated by loop diagrams BTeV is sensitive to mass scales of up to few TeV.
- The New Physics effects in these loops may be the _only_ way to distinguish among models.
- Masiero & Vives: *“the relevance of SUSY searches in rare processes is not confined to the usually quoted possibility that indirect searches can arrive ‘first’ in signaling the presence of SUSY. Even after the possible direct observation of SUSY particles, the importance of FCNC & CPV in testing SUSY remains of utmost relevance. They are & will be complementary to the Tevatron & LHC establishing low energy supersymmetry as the response to the electroweak breaking puzzle”** *(hep-ph/0104027)
- We agree, except we would replace “SUSY” with “New Physics”

- Rob Kutschke, Fermilab

- June 21, 2002

## Comparison with LHC-b

- Advantages of LHCb
- 5 higher b cross-section; 1.6  higher b/tot.
- Advantages of BTeV
- Detached vertex trigger at level 1.
- Enabling technologies:
- Magnet on the IR: we can reject low p tracks at level 1.
- Pixels: very low occupancy, only 6mm from beam ( cf 1 cm ).
- Allows us to trigger on very general properties of b’s.
- PbWO4 Ecal with CLEO/BaBar/Belle-like performance.
- Trigger/DA design lets us read out 5 as many b’s/second.

- Rob Kutschke, Fermilab

- June 21, 2002

## Comments on the e+eSuper B-Factories

- At the Y(4S), it would take a 1036/cm2/s e+e- collider to match the performance of BTeV for Bo & B±.
- There would be no competition on Bs, b, ...
- KEK is only proposing 1035/cm2/s.
- For Super-BaBar there are serious technical problems for both the machine & the detector.
- We believe the cost will far exceed that of BTeV. Recent HEPAP subpanel mentions $500M.

- Rob Kutschke, Fermilab

- June 21, 2002

## Summary and Conclusions

- The Fermilab director has given Stage I approval to a revised proposal to run BTeV with only one arm fully instrumented.
- In the RICH detector, the aerogel radiator has been replaced with liquid C5F12.
- We have learned use the RICH for lepton ID:
- Single(double) lepton ID efficiency up ×2.4 (×3.9).
- The reduced scope BTeV remains an excellent detector and will be a leader in b and c physics in the last half of this decade.

- Rob Kutschke, Fermilab

- June 21, 2002

## Summary of CKM Physics Reach (107 s)

- J/l+l-

|      Reaction |  B (B)(x10-6) | # of Events | S/B |    Parameter | Error or (Value) |
| --- | --- | --- | --- | --- | --- |
| Bo+- |          4.5 |    14,600 |    3 |   Asymmetry |       0.030 |
| Bs Ds K- |      300 |       7500 |    7 |        |          8o |
| BoJ/KS  , J/l+ l- |      445 |  168,000 |  10 |      sin(2) |       0.017 |
| Bs Ds- |    3000 |    59,000 |    3 |          xs |         (75) |
| B-Do (K+-) K- |        0.17 |         170 |    1 |  |           |
| B-Do (K+K-) K- |        1.1 |      1,000 | >10 |        |          13o |
| B-KS - |       12.1 |      4,600 |     1 |  |       <4o  + |
| BoK+- |       18.8 |    62,100 |   20 |        |  theory errors       |
| Bo+- |       28 |      5,400 |   4.1 |  |  |
| Booo |         5 |         780 |   0.3 |  |          ~4o |
| BsJ/ |     330 |      2,800 |   15 |  |  |
| BsJ/ |     670 |      9,800 |   30 |            |        0.024 |

- Rob Kutschke, Fermilab

- June 21, 2002

**Notes:**
Point out that there are several ways to measure , so can resolve ambiguities; other ways of resolving ambiguities in beta.
Error estimate on alpha is a guess. Can do better on chi by using electron modes. 

## Backup  Slides

- Rob Kutschke, Fermilab

- June 21, 2002

## Specific Comparisons with LHC-b 

|    Mode |      BR | 
Yield | 
S/B |    
Yield | 
   S/B |
| --- | --- | --- | --- | --- | --- |
| Bs Ds K- |  3.0x10-4 | 7530 |     7 | 7660 |     7 |
| Bo+- |  2.8x10-5
 |   5400 |  4.1 | 2140 |  0.8 |
| Booo |  0.5x10-5
 |     776 |  0.3 |   880 | not known |

- BTeV

- LHC-b

- Rob Kutschke, Fermilab

- June 21, 2002

## Comparisons With Current e+e- B factories

- Number of flavor tagged Bo+  - (B=0.45x10-5)
- Number of B-Do  - (Full product B=1.7x10-7)
- Bs , Bc and b not done at Y(4S) e+e- machines

- Rob Kutschke, Fermilab

- June 21, 2002

## Reconstructed Events in New Physics Modes: Comparison of BTeV with B-factories

|         Mode |          BTeV (107s) |  |  |    B-fact (500 fb-1) |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  |  Yield | Tagged | S/B | Yield | Tagged | S/B |
| BsJ/ | 12650 |   1645    | >15 |    - |     - |  |
| B-K- | 11000 | 11000 | >10 |   700 |   700 |    4 |
| BoKs |   2000 |     200 |  5.2 |   250 |     75 |    4 |
| BoK*+-   |   2530 |   2530 |   11 |   ~50 |   ~50 |    3 |
| Bs +-  |         6 |      0.7 | >15 |       0 |     |  |
| Bo+-   |         1 |      0.1 | >10 |       0 |   |  |
| D*++Do,  DoK+ |   ~108 |   ~108 | large | 8x105 | 8x105 | large |

- Rob Kutschke, Fermilab

- June 21, 2002

## Summary of Required Measurements for CKM Tests

- Rob Kutschke, Fermilab

- June 21, 2002

## Offline Computing Model

- Reuse Level 2/3 trigger farm.
- 2500-4000 Linux processors
- Sized to deal with peak lumi.
- About 2/3 of cycles are available for other uses:
- Lower lumi late in run.
- Machine filling, downtime etc
- Use of large computing clusters at universities.
- Grid aware but not grid dependent.
- See talk by Joel Butler Tuesday afternoon.

- Rob Kutschke, Fermilab

- June 21, 2002

##  Changes in Efficiencies wrt Proposal 

- We lost one arm: Factor = 0.5
- We gained on leptons:
- We now use RICH to improve lepton ID:
- Larger solid angle; larger momentum range.
- In proposal we used only +-, now we include e+e-
- Factor = 2.4 (or 3.9), depending on whether analysis required one or two leptons to be ID’ed.
- DA bandwidth constant for one arm: Factor = 1.15
- For Bs only: improved D2: Factor = 1.3

- Rob Kutschke, Fermilab

- June 21, 2002

## Summary of Efficiency Changes 

|     Mode [Quantity] | Yield in Proposal |  Yield Factors  | New Yield | New D2 | Sensitivity |  |
| --- | --- | --- | --- | --- | --- | --- |
|  |  |  |  |  | Proposal  | One Arm |
| BoJ/ Ks
  [sin(2)] | 80,500 | 0.5*3.9*
1.15=2.24 | 168,000
 | 0.10 | 0.025 | 0.017 |
| BsJ/()
 [sin(2)] |   9,940 | 0.5*2.4*
1.15=1.38 | 12,600 | 0.13 | 0.033 | 0.024 |
| Bs Ds K [] | 13,100 |  0.5*1.15
      =0.58 |   7,500 | 0.13 |      6o |      8o  |

-  In the proposal all D2 were 0.10.

- Rob Kutschke, Fermilab

- June 21, 2002