# Presentation: 613736

## The BTeV Experiment

- _Outline_
- Physics Goal
- The one-arm spectrometer
- Physics sensitivities
- Status

## BTeV—as of March 2002

**Belarussian State-**** **D .Drobychev,
- A. Lobko, A. Lopatrik, R. Zouversky
**UC Davis ****- **P. Yager
**Univ. of Colorado-**J. Cumalat
**Fermi National Lab **
- J. Appel, E. Barsotti, C. N. Brown ,
- J. Butler, H. Cheung, G. Chiodini,
- D. Christian, S. Cihangir, R. Coluucia,
- I. Gaines, P. Garbincius, L.  Garren,
- E. Gottschalk, A. Hahn,  P. Kasper,
-  P.  Kasper, R. Kutschke,  S.  Kwan,
- P.  Lebrun,  P. McBride,  M. Votava,
- M.  Wang, J.  Yarba
**Univ. of Florida at Gainesville**** **
- P. Avery
**University of Houston**** **
- M. Bukhari, K. Lau, B. W. Mayes,
- V. Rodriguez,  S. Subramania
**Illinois Institute of Technology**
- R. A. Burnstein, D. M. Kaplan,
- L. M. Lederman, H. A. Rubin,
- C. White

**Univ. of Illinois- **M. Haney,
- D. Kim, M. Selen, J. Wiss** **
**Univ. of Insubria in Como-**
- P. Ratcliffe, M. Rovere
**INFN - Frascati**- M. Bertani,
- L. Benussi, S. Bianco, M. Caponero,
- F. Fabbri, F. Felli, M. Giardoni,
- A. La Monaca, E. Pace, M. Pallotta,
- A. Paolozzi
**INFN - Milano** - G. Alimonti,  P.
- D’Angelo, L. Edera,  S. Magni, D.
- Menasce, L. Moroni, D. Pedrini,
- S.Sala, L. Uplegger
**INFN - Pavia ****- **G. Boca,
-  G. Liguori, & P. Torre
**INFN - Torino** –
- R. Arcidiacono, S. Argiro,
- S. Bagnasco, N. Cartiglia, R. Cester,
- F. Marchetto, E. Menichetti,
- R. Mussa, N. Pastrone
**IHEP Protvino, Russia **
- A. Derevschikov, Y. Goncharenko,
- V. Khodyrev, V. Kravtsov,  A.
- Meschanin,  V. Mochalov,

- D. Morozov, L.  Nogach, K. Shestermanov, L. Soloviev,  A. Uzunian, A.  Vasiliev
**University of Iowa                 **C. Newsom, & R. Braunger **University of Minnesota**      V. V. Frolov, Y. Kubota, R. Poling, & A. Smith  ** **
**Nanjing Univ. (China)**
- T. Y. Chen, D. Gao, S. Du, M. Qi,  B. P. Zhang, Z. Xi Zhang,  J. W. Zhao
**Ohio State University**
- K. Honscheid, & H. Kagan
**Univ. of Pennsylvania**
- W. Selove
**Univ. of Puerto Rico       **
- A. Lopez, & W. Xiong
**Univ. of Science & Tech. of China -** G. Datao, L. Hao, Ge Jin, T. Yang, & X. Q. Yu                **Shandong Univ. (China)**- C. F. Feng, Yu Fu, Mao He, J. Y. Li,  L. Xue, N. Zhang, & X. Y. Zhang

**Southern Methodist University - **T. Coan
**SUNY Albany - ** M. Alam **Syracuse University**
- M. Artuso, S. Blusk, C. Boulahouache, O. Dorjkhaidav, K. Khroustalev, R.Mountain, N. Raja, T. Skwarnicki, S. Stone, J. C. Wang
**Univ. of Tennessee        **
- T. Handler,  R. Mitchell                           **Vanderbilt University **
- W. Johns, P. Sheldon,   K. Stenson, E. Vaandering,  & M. Webster
**Univ. of Virginia: **
- M. Arenton, S. Conetti, B. Cox,
**A. Ledovskoy**
**Wayne State University**
- G. Bonvicini, & D. Cinabro,
- A. Shreiner
**University of Wisconsin **
- M. Sheaff
**York University**
- S. Menary

## Physics Goals

- BTeV is designed to search for physics beyond Standard Model and make precise measurements of SM parameters.
- The important measurements to make involve mixing, CP violation and rare decays of hadrons containing *b* or *c *quarks, especially:
- CP violation in Bo , Bs and Do mesons.
- Bs mixing and s.
- Rare b decays.
-       A window to new physics

## The CKM Matrix and Phases

- The CP violation in the SM originates from quark mixing.
- The Unitarity of the CKM matrix allows us to construct 6 triangles, the most common beauty triangle is the bd triangle.
- The primary goal is to measure CKM phases: 
- It is also important to measure the lengths of the sides (magnitudes).
- It is important to remove the 4-fold ambiguity generated by sin(.

- 

- 

- 

- 

- 

- Constraint:  

## Required Measurements for CKM Tests

- The BTeV detector is unique that satisfies all these requirements.

## A Forward Detector at pp Collider

- Forward region, 10300 mrad, 1.5 <| <3.5

**BTeV**

## The Tevatron as b & c Source

## The BTeV Spectrometer

## The BTeV Pixel Detector

- Provides extremely high quality precision space points for vertex reconstruction, which are also used in the detached vertex trigger.
- Reasons for pixel detector:
- Superior signal to noise.
- Excellent spatial resolution (5-10 m).
- Very low occupancy.
- Radiation hard.
- Very fast.
- Special features:
- Directly used in the level 1 trigger.
- Pulse height is measured on every channel with a 3-bit FADC.
- It is inside a dipole and gives a standalone momentum.

- Pixels size:  50 m  400 m

## Performance of the Pixel Detector

- B 
- <L>/L=36  at pB=30GeV

- Spatial Resolution from Beam Test 1999

- Large Ldecay / L is critical for b experiment

## Ring Imaging Cherenkov Detector

- Cherenkov angle vs P

**Liquid C****5****F****12**** (n=1.24)**

**Gas C****4****F****10**** ****(n=1.00138)**

- The RICH provides identification of kaons and pions.
- It is essential to CP violation study

## Lepton Identification Using RICH

- While the full detector aperture is 300 mr, the acceptance of the electromagnetic calorimeter and muon detector is only ~200 mr.
- The RICH, however, has both e/ and  discrimination  at low momentum. The wide angle particles are mostly at low momentum!

- BJ/X

## Electromagnetic Calorimeter

- EM calorimeter for  reconstruction and electron ID.
- 10,000 PbWO4 crystal (rad hard) with PMT readout
- Lateral size: 27.227.2mm2 (front), 2828mm2 (back), Length 22cm (25 X0)
- Resolution:E/E = 0.8% for in BK*,  M = 2.6 MeV for 10 GeV .
- Sample crystals tested in a beam at Protvino.

## Detached Vertex Trigger

-  Idea:   finds the primary vertex,  selects events that have additional tracks miss it
-  Requirement:  at least 2 tracks detached by more than 6     1% minimum bias at level 1 trigger.
- Refined reconstruction at level 2 and 3.
- With  3-level trigger scheme, the event rate:
- Efficiency: (after the other analyses cuts)

- 7.6 MHz  3 kHz

## Physics Reach (CKM) in 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 |       sin(2 |        0.024 |

- Critical check to the SM

## Critical Checks Using 

- Silva & Wolfenstein (hep-ph/9610208), (Aleksan, Kayser & London), propose a test of the SM, that can reveal new physics; it relies on measuring the angle .
- BTeV can use CP eigenstates in Bs decay to measure for example 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

## Rare b Decays

- Sensitive to high mass gauge bosons and fermions. It is a good place to find new physics.
- Exclusive Rare Decays such as BBK*+: Dalitz plot & polarization
- Inclusive Rare Decays such as inclusive bs, bd, bs+

| Reaction |  B (10-6) | Signal/Year | S/B | Physics |
| --- | --- | --- | --- | --- |
| BoK*o+- |      1.5 |   2530 |  11 |  polarization & rate |
| B-K-+-
 |      0.4 |   1470 | 3.2 |  rate |
| bs+-
 |      5.7 |   4140 | 0.13 |  rate: Wilson coefficents |

## MSSM Measurements (from Hinchcliff & Kersting hep-ph/0003090)

- MSSM Measurements (from Hinchcliff & Kersting hep-ph/0003090)

- Contributions to Bs mixing

- Contributions to direct CP violating decay

- Asym=(MW/msquark)2sin(), ~0 in SM

- B-K-

- CP asymmetry  0.1sincossin(mst), ~10 x SM

- BsJ

## 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- |   6325 |   6325 | >10 |   700 |   700 |    4 |
| BoKs |   1150 |     115 |  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 |

## Specific Comparisons with LHC-b

- Yields in two final states

|    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

## Status

- BTeV received a second unanimous approval by the Fermilab PAC (4/2002).
- Detector costs have been reduced from ~180 M$ to ~110 M$ (includes G&A and 30% contingency). Full “Temple” review in 9/2002.
- P5 or equivalent review for DOE in Fall 2002.

- PAC Recommendation
*“ ... **BTeV has designed and prototyped an ambitious trigger that will use B decay displaced vertices as its primary criterion. This capability, together with BTeV’s excellent electromagnetic calorimetry and particle ID and enormous yields, will allow this experiment to study a broad array of B and B**s** decays. BTeV has a broader physics reach than LHCb and should provide definitive measurements of CKM parameters and the most sensitive tests for new physics in the flavor sector.”*