# Presentation: 501877

## BTeV - Status and Perspectives 

- BTeV - Status and Perspectives

-   Physics Goals - My Perspective
-   Detector Description and R&D
-   Comparisons to other experiments
-   Status

## Physics Goals:                          My perspective on one slide

-  The Standard Model CKM matrix is very predictive                                                     e.g. all quark CP-violation is described by  (i.e. 1 parameter)
-  To discover new physics (or help interpret new physics discovered elsewhere) we need a comprehensive study of quark flavour physics
-   Need to measure “”, , ,  in many modes/decays
-   Look at rare b decays and mixing
-   Look at CP-violation and rare decays in charm
-   Check flavour independence with kaon decays

-  Compare to the comprehensive tests of EW at LEP and SLD - repeat for quark flavour physics!
-           So don’t just look under one lamp post!

## Requirements for Measurements

| Physics Quantity | Decay Mode | Vertex Trigger | K/ Sep |  Det | Decay Time  |
| --- | --- | --- | --- | --- | --- |
| sin(2) | B0    +-0 |  |  |  |  |
| cos(2) | B0    +-0 |  |  |  |  |
| sin() | Bs  DsK- |  |  |  |  |
| sin() | B0  D0K- |  |  |  |  |
| sin(2) | Bs J/, J/ |  |  |  |  |
| sin(2) | B0 J/ Ks |  |  |  |  |
| cos(2) | B0 J/ K0, K0 l |  |  |  |  |
| xs | Bs  Ds - |  |  |  |  |
|  for Bs | Bs J/(), K+K-, Ds |  |  |  |  |

-  Precision: Large samples of decays, flavour tagged for CP-violation
-  Comprehensive: B+, Bd, Bs, Bc, b-baryon and charm decays
- Efficient reconstruction for “all” decays, including  and 0’s
- Excellent flavour tagging

## BTeV Collaboration

**Belarussian State: **D .Drobychev,
- A. Lobko, A. Lopatrik, R. Zouversky
**UC Davis:**** **P. Yager
**Univ. of Colorado:**** **
- J. Cumalat, P. Rankin, K. Stenson
**Fermilab:**** **
- J. Appel, E. Barsotti, C. N. Brown ,
- J. Butler, H. Cheung, D. Christian,
- S. Cihangir,  I. Gaines,  P. Garbincius,
- L.  Garren, E. Gottschalk, G. Jackson,
- A. Hahn, P. Kasper,  P.  Kasper,
- R. Kutschke, S.  Kwan, P.  Lebrun,
- P. McBride, J. Slaughter, M. Votava,
- M.  Wang, J.  Yarba
**Univ. of Florida at Gainesville: **
- P. Avery
**University of Houston: **
- A. Daniel,  K. Lau, M. Ispiryan,
- B. W. Mayes,  V. Rodriguez,
- S. Subramania, G. Xu
**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,
- V. Simaitis, 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,
- M.Dinardo, L. Edera,  D. Lunesu,
- S.Magni, D. Menasce, L. Moroni,
- D. Pedrini,  S.Sala, L. Uplegger
**INFN - Pavia: **G. Boca,
- G. Cosssali, G.  Liguori, F.Manfredi,
- M. Manghisoni, M. Marengo,
- L. Ratti, V. Re, M. Santini,
- V. Speziali, P. Torre, G. Traversi
**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:**      J. Hietala, Y. Kubota, B. Lang, 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 Univ:**
- T. Coan, M. Hosack
**SUNY Albany:**** **M. Alam

**Syracuse University:**
- M. Artuso, S. Blusk, J. Butt,
- C. Boulahouache,
- O. Dorjkhaidav, J. Haynes,
- N. Menaa, R. Mountain, N.Nandakumar, L. Redjimi,
- R. Sia, T. Skwarnicki, S. Stone,
- J. C. Wang, K. Zhang
**Univ. of Tennessee:**
- T. Handler,  R. Mitchell                           **Vanderbilt University:**
- W. Johns, P. Sheldon,
- E. Vaandering, M. Webster
**Univ. of Virginia: **
- M. Arenton, S. Conetti, B. Cox,
- A. Ledovskoy, H. Powell,
- M. Ronquest, D. Smith,
- B. Stephens, Z. Zhe
**Wayne State University:**
- G. Bonvicini, D. Cinabro,
- A. Shreiner
**University of Wisconsin:**
- M. Sheaff
**York University:** S. Menary

## Why do b and c Physics at Tevatron?

-   Large samples of b quarks
-   Get  41011 b hadrons per 107s at L = 21032 cm-2s-1
-   For e+e- at (4S) get 2108 B hadrons per 107s at 1034 cm-2s-1

-   Bs, b and other b-flavored hadrons are accessible at the Tevatron
-   Charm rates are  10 larger than b rates

- Why look in the Forward Region?

- b production angle

- b production
-    angle

- (-ln(tan[/2])

-   Decay length
- separation
-   Less MCS
-   More BB in
- detector
-   Better away-side
- tagging

## The BTeV Detector

-   Vertex pixel (50m  400m)
-     detector in dipole magnet
-   RICH for particle ID
-   PbWO4 crystal EM calorimeter
-   Vertex separation Trigger at L1
-     (primary vertex reconstructed)
-   Powerful high speed DAQ
-     (output rate at 4KHz)

- Main/Unique Features

## Pixel Vertex Detector

**  ****Achieved design  (****5-10 micron****) **
**   ****resolution**** in 1999 FNAL test**
**   ****beam run. **
**  ****Demonstrated ****radiation**
**   ****hardness**** in exposures at IUCF.**
**  ****The ****final readout chip**** has been**
**   ****bench tested and will undergo**
**   ****final testing in FNAL test-beam**
**   ****in 2003.**

## Ring Imaging Cerenkov Counter

-   Gas radiator (C4F10) detected on planes of Hybrid Photodiodes
-   Liquid radiator (C5F12) detected on array of side mounted PMTs

- Beam

- Mirrorat backend

- HPDEnclosurewill be here

- Enclosure
- for
- RICH
- beam test

-  Developing a 163
-   pixel HPD
-  Bench test at
-   Syracuse showing
-   pulse height
-   distribution from
-   prototype

-  Also testing
-    MAPMTs

## Lead Tungstate EM Calorimeter

-   PbWO4 2828mm2  22cm crystals
-    pioneered by CMS, but BTeV uses PMTs
-   Excellent energy and spatial resolution
-   Resolution measured at IHEP/Protvino
-    beam tests (Stochastic term = 1.8%)

- Multiple vendors
- (Bogoriditsk, Russia
-  and Shanghai, China)

## BTeV Trigger

-  Reconstructs primary
-   vertex and looks for
-   detached decays every
-   crossing
-  Made possible by vertex
-   detector (3D space points
-   with excellent resolution
-   and low occupancy)
-  Pipelined and parallel
-   processing with 1 TB of
-   buffer
-  3 Stage Trigger
-      L1:FPGAs and DSPs
-      L2/L3: Linux PCs

**7.6 MHz**

**15 GB/s**

**200 MB/s**

**75 KHz**

**7.5 KHz / 4 KHz**

**4 KHz**

- 1-2 Petabytes per year

**800 GB/s**

## BTeV L1 Pixel Trigger

- b,b/b

- Finds primary vertex and looks for
- At least 2 tracks that miss it with:
-  pT2 > 0.25 (GeV/c)2
-  b > 4.4b
-  b < 2mm

- 100/1 rejection of min-bias events

-   Timing tests show we are already close to
-     the required < 350 s L1 latency
-   Speed is low by 2.7 w/old DSP
-                               1.8 w/new DSP
- No need for hand optimized assembly code!

- L1 Vertex Trigger prototype

## BTeV DAQ

-   Changed custom switch to a
-    commercial one to lower risk.
-   DAQ is divided into
-    8 “Highways”
-   Output data is DST and saved
-    on disk (with duplication)

## Fault Tolerance in Trigger and DAQ

-   Researching the design and implementation of  high-performance,
-    heterogeneous, fault-tolerant and fault-adaptive real-time systems that
-    are embedded (*i.e. *are an integral part of the hardware they serve)
-   Contains an educational outreach program where high school teachers
-    take part in the research and develop WEB lessons for their students
-    (Summer programs at Fermilab and Pittsburgh, integrated with
-    QuarkNet, Link-to-Learn and College in High School programs)

-   Outcome of BTeV’s response to an early review on complexity of system
-    is a research program on Real Time Embedded Systems Research (RTES)
-   A collaborative effort between computer scientists and BTeV physicists
-    funded by the NSF ($5M over five years)

**Illinois**

**Pittsburgh**

**Syracuse**

**Vanderbilt**

**Fermilab**

**NSF**

## Physics Reach CKM in 107 s (Model Independent)

| Decay | B(B) (x10-6) | # Events | S/B | Parameter | Error or (Value) |
| --- | --- | --- | --- | --- | --- |
| Bs Ds K- | 300 | 7500 | 7 |  -  |  8o |
| Bs Ds- | 3000 | 59,000 | 3 | xs | (75) |
| B0J/KS   J/l+ l- | 445 | 168,000 | 10 | sin(2) | 0.017 |
| B0J/K0, K0  l  | 7 |  250 | 2.3 | cos(2) | ~0.5 |
| B-D0 (K+-) K- | 0.17 | 170 | 1 |  |          
13o |
| B-D0 (K+K-) K- | 1.1 | 1,000 | >10 |  |  |
| BsJ/ | 330 | 2,800 |   15 | sin(2 | 0.024 |
| BsJ/ | 670 | 9,800 |   30 |  |  |
| B0+- | 28 | 5,400 |  4.1 |  | ~ 4o |
| B000 | 5 | 780 |  0.3 |  |  |

## Physics Reach Rare Decays

| Decay |  B (10-6) | Signal | 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 coefficients |

- BTeV “data” compared to Burdman et al. Calculation for K*l+l-
- One year for K*l+l- could be enough to determine if New Physics is present

## Operation at 396 ns Bunch Crossing

-   BTeV was designed for L = 21032 cm-2s-1 at 132 ns
-    i.e. 2 interactions/crossing
-   Now expect L ~ 21032 cm-2s-1 at 396 ns, i.e. 6 int/crossing
-                 or L ~ 1.31032 cm-2s-1 at 396 ns, i.e. 4 int/crossing
-   Verified performance by repeating many of the simulations
-    at 4 and 6 int/crossing (without re-optimizing the code)
-    Average impact across store is ~10%
-   Key potential problems areas - trigger, EMCAL and RICH all
-    hold up well based on simulations
-   Ongoing work to understand fully the impact of a change to
-    396 ns bunch spacing, a “396 ns impact” document is being prepared.

## Charm Physics Potential

- Flexible trigger and high rate DAQ - potential to find New Physics

-   D0-D0 Mixing: Box diagram:     mDSD/ < 110-4
-                             LD Dispersive: mDLD/ ~ 210-4
-                             LD HQET:       mDLD/ ~ (1 to 2)10-5
-     SM Contribution:  mDSM/ < 110-4
-     Current experimental limit mD/ < 0.1 Lots of Discovery room!
-   CP Violation: Possibly observe SM CP violation in charm!
-     SM: ACP  2.810-3 for D+  K*0K+
-             ACP  -8.110-3 for Ds+  K*+
-             Expect (ACP) = 110-3 for 106 background-free events
-     Excellent D* tag (efficiency  25%)
-     Geant simulation gives # reconstructed D0K > 108

- BTeV has the necessary detectors, trigger and DAQ for charm

## Comparisons to Belle/BaBar

-  No Bs, Bc and b at B-factories (no comprehensive study)
-  Number of flavor tagged B0+- (BR=0.4510-5)

|  | L(cm-2s-1) |  | #B0/107s | rec | D2 | #tagged |
| --- | --- | --- | --- | --- | --- | --- |
| e+e- | 1034 | 1.1nb | 1.1108 | 0.45 | 0.26 | 56 |
| BTeV | 21032 | 100b | 1.51011 | 0.021 | 0.1 | 1426 |

-  Number of B-D0K- (Full product BR=1.710-7)

|  | L(cm-2s-1) |  | #B0/107s | rec | # |
| --- | --- | --- | --- | --- | --- |
| e+e- | 1034 | 1.1nb | 1.1108 | 0.4 | 5 |
| BTeV | 21032 | 100b | 1.51011 | 0.007 | 176 |

## Events in New Physics Modes: Comparison with B-Factories

| Mode | BTeV (107s) |  |  | B-Factory (500 fb-1) |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  | Yield | Tagged | S/B | Yield | Tagged | S/B |
| BsJ/() | 12650 | 1645 | >15 | - | - | - |
| B- K- | 11000 | n/a | >10 | 700 | 700 | 4 |
| B0 Ks | 2000 | 200 | 5.2 | 250 | 75 | 4 |
| B0 K*+- | 2530 | n/a | 11 | ~50 | ~50 | 3 |
| Bs +- | 6 | 0.7 | >15 | - | - | - |
| B0 +- | 1 | 0.1 | >10 | 0 | - | - |
| D*+D0+,D0K+ | ~108 | ~108 | large | 8105 | 8105 | large |

## Comparison to Super-KEK

-   KEK-B plans for L=1035 cm-2s-1 in 2007, (10 original design)
-   Numbers in previous tables still not competitive with BTeV
-   Problems for detectors (See E2 report at Snowmass)

- Comparison to Super-BaBar

-   Proposal for L=1036cm-2s-1 (>100 original design)
-   Would be competitive with BTeV in B0 and B+ Physics
-   Still could not do Bs, Bc and b
-   Serious technical problems to overcome for both the machine
-    and detector
-   We believe the cost will far exceed that of BTeV
-    (Recent HEPAP subpanel mentions $500M)

## Comparison to LHCb

-  Competition is LHCb
-    bb(LHCb) = 5bb(BTeV)
-    tot(LHCb) = 1.6tot(BTeV)
-  Interactions/Crossing
-      3 lower than BTeV

- However
- BTeV has
- Many
- Advantages!

## Comparison to LHCb II

-   BTeV is designed around a pixel detector with less occupancy,
-     allows for a detached vertex trigger at the first level trigger
-   Large samples of rare hadronic and charm decays
-   BTeV can run with multiple interactions per crossing
-   BTeV vertex detector in magnetic field allows rejection of
-     low momentum (high MCS) tracks in the trigger
-   BTeV has a (20) higher rate DAQ - more b and _c decays_
-   BTeV will have a much better EM calorimeter - more
-     comprehensive study of decays
-   LHCb are currently extensively changing their design beyond TDR:
-   Reduced # silicon planes and thickness, # tracking stations
-   Put magnetic field in interaction region (remove shield-RICH)
-   Added high pT only trigger (for Bh+h-)
-   Allow multiple interactions per crossing

## Comparison to LHCb III

-  Compare to preliminary (April 2003) LHCb light #s

-  Compare to LHCb TDR #s (LHCb light #s ready in fall TDR #s)

| Mode | BR | LHCb |  | BTeV |  |
| --- | --- | --- | --- | --- | --- |
|  |  | Yield | S/B | Yield | S/B |
| BsJ/() | 1.010-3 | - | - | 12650 | >15 |
| B0+- | 2.810-5 | 2140 | 0.8 | 5400 | 4.1 |
| B000 | 0.510-5 | 880 | unknown | 776 | 0.3 |

| Mode | BR (10-5) | LHCb Untag Yield |  | BTeV (Yield scaled to BR) |
| --- | --- | --- | --- | --- |
|  |  | TDR | Light |  |
| BsDs- | 300 | 86000 | 72000 | 59000 |
| BsDsK- | 23 | 6000 | 8000 | 5900 |

-   BTeV superior for photons/0 and more comprehensive data set

## Brief History and Status of BTeV

-  May 1997 - EOI, 161 pages
-  Dec. 1997 - Addendum, 62 pages - address PAC concerns
-          BTeV becomes a R&D project
-  May 1999 - Preliminary TDR, 373 pages (full BTeV)
-  May 2000 - Proposal, 429 pages, submitted to Fermilab
-    June 2000  PAC unanimously recommends Stage 1 approval
-                      Approval from Director (2-arms)
-  Mar. 2002 - Proposal update, 126 pages (request from Lab, 1-arm)
-           PAC unanimously recommends approval of descoped BTeV
-           Approval from Director
-  Oct. 2002 - Fermilab conducts cost review of BTeV (Temple)
-  Mar. 2003 - Review of BTeV by P5
-     Oct. 2003 - P5 supports building BTeV and recommends earliest construction

- What it takes to get an experiment approved “now”

## Continual interest in BTeV

-   Despite long review and approval process and problems for
-     universities getting funding (e.g. for R&D):

-  Shows there is a very strong interest in the physics and technology
-    of BTeV

## Summary I

-  From the PAC report of June 2000 on 2-arm BTeV:
- “The Committee believes that BTeV has the potential to be central part of an excellent Fermilab physics program in the era of the LHC. With excitement about the science and enthusiasm for the elegant and challenging detector, the Committee unanimously recommends Stage I approval for BTeV”
-  From  the April 2002 PAC recommendations on updated BTeV:
- “The Committee once again recommends Stage I approval for BTeV. Although the composition of the committee has changed substantially since 2000, this recommendation is again unanimous.”
-  From the September 2003 P5 report to HEPAP:
- “P5 supports the construction of BTeV as an important project in the world-wide quark flavor physics area. Subject to constraints within the HEP budget, we strongly recommend an earlier BTeV construction profile and enhanced C0 optics.”

## Summary II

-   If we get DOE approval and funding:

- We are excited about BTeV and eager to get construction funded and started!