the silicon track trigger stt at d
Download
Skip this Video
Download Presentation
The Silicon Track Trigger STT at D

Loading in 2 Seconds...

play fullscreen
1 / 16

The Silicon Track Trigger STT at D - PowerPoint PPT Presentation


  • 310 Views
  • Uploaded on

Beauty 2005 in Assisi, June 2005. Sascha Caron. for the D collaboration. Tag. beauty. fast ... Including beam spot size 35 m. and 15 m SMT resolution. page 11. The ...

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The Silicon Track Trigger STT at D' - Kelvin_Ajay


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
the silicon track trigger stt at d

The Silicon Track Trigger (STT) at DØ

Beauty 2005 in Assisi, June 2005

Tag

fast …

beauty

Sascha Caron

for the DØ collaboration

slide2
The Silicon Track Trigger at DØ
  • OUTLINE
  • - D0 detector
  • D0 trigger
  • What is the STT?
  • dataflow
  • clustering and tracking
  • B identification
  • Performance
  • Summary

page 1

Sascha Caron

slide3
The Silicon Track Trigger at DØ

D0 in Run II

The Silicon Track Trigger is based

on information

of the :

Silicon Microstrip

Tracker

Central Fiber Tracker

page 2

Sascha Caron

slide4
The Silicon Track Trigger at DØ

D0 in Run II

The Silicon Track

Trigger is based

on information

of the :

Silicon Microstrip

Tracker

Central Fiber

Tracker

  • 50 μm pitch strips (parallel to beam)
  • 800000 readout channels
  • Only axial strips used for STT tracks
  • Scintillating fibers
  • Coverage: |Rapidity| < 1.7

page 3

Sascha Caron

slide5
The Silicon Track Trigger at DØ

Events

per

second

QCD ET>30 GeV

dijet production

Aim: High ET

Z->bb, HZ->bbvv, H->bb, etc.

Hopefully B physics

10

1

b-jets ET>30 GeV

Find b-events

early to keep

high efficiency

at an acceptable

rate

0.1

0.01

Z-> b bbar

0.001

Higgs->b bbar

Events for

L=100 E30 cm-2/s

= about 8 pb-1/day

0.0001

ZH-> bbvv, bH->bbb etc.

page 4

Sascha Caron

slide6
The Silicon Track Trigger at DØ

Principal Idea

B decay products

B decay length is mm

Interaction point

is mean beam spot

Impact parameter

(2d in x-y plane)

  • Silicon Improved Tracks with
  • 2d impact parameter
  • Select events with large impact parameter tracks

page 5

Sascha Caron

slide7
The Silicon Track Trigger at DØ

Trigger System

p p bunch crossing frequency

¯

L1 Trigger

decision time

about 4 μs

(1500) 5000 Hz

L2 Trigger

decision time

about 200 μs

(700)

1000Hz

L3 Trigger

decision time

about 50 ms

2.5MHz

50 Hz

  • Hardware based
  • CTT tracks, calorimeter towers, muons
  • Hardware/Software
  • simple jets, electrons, muons, taus
  • Silicon Microvertex improved tracks (STT)
  • global processor to combine information
  • (e.g. STT tracks for Bid)
  • Software based
  • partial event
  • reconstruction

page 6

Sascha Caron

slide8
The Silicon Track Trigger at DØ

other

L2 pre-

processors

Data flow chart L2 tracks

L2

CTT

L2

Global

Central

Fiber

Tracker

L1

CTT

L2

STT

Silicon

Micro

Detector

Detector

Detector

Level 1

Level 1

Level 2

page 7

Sascha Caron

slide9
The Silicon Track Trigger at DØ

How is the

tracking improved?

  • Tracks found at L1 with the Central Fiber Tracker are used to define roads into the Silicon
  • Silicon hits are clustered
  • Track is re-fit within the road

page 8

Sascha Caron

slide10
The Silicon Track Trigger at DØ

Silicon Track Trigger cards

Road data to

Fiber Road Card

Fitting done

in Track Fit Card

Done in parallel for each

of the 12 sectors

2 sectors in 1 crate

-> 6 Crates with

1 Fiber Road Card

9 Silicon Trigger Cards

2 Track Fit Cards

SMT data to

9 Silicon Trigger

Cards

L2CTT

page 9

Sascha Caron

slide11
The Silicon Track Trigger at DØ

Silicon Track Trigger cards

Road data to

Fiber Road Card

  • - Receives and distributes L1 tracks
  • Communicates with Trigger
  • framework

SMT data to

Silicon Trigger

Cards

Fitting done

in Track Fit Card

- Perform clustering and cluster-road matching

- Clusters SMT hits + pedestal correction

- Axial clusters are matched to the roads

  • - receives road and axial clusters
  • convert to physics coordinates via LUT
  • perform track fit φ(r)= b/r+kr+φ0
  • beam spot correction
  • output tracks to L2CTT

page 9

Sascha Caron

slide12
The Silicon Track Trigger at DØ

Performance studies STT tracks

Impact Parameter resolution

Correlation to RECO

Resolution in μm

pT(GeV)

Purity

Including beam spot size 35 μm

and 15 μm SMT resolution

page 10

Sascha Caron

slide13
The Silicon Track Trigger at DØ

B identification

Signal to Background ratio

Ri

Store 2d signal (b events) to background (light quarks) ratio into a lookup table

1.5 mm

b/db

- Fast, simple and efficient technique

- Time needed is 2 operations per track and goes linear with the number of tracks -> about 1-5 μs

- Degrades bad tracks without cutting them

page 11

Sascha Caron

slide14
The Silicon Track Trigger at DØ

Performance studies

L2 B-id likelihood

efficiency Z->bb

Red :

Simple Cut

Blue/Green:

B-id

Very well separation of signal and

background events

Large background reduction

with L2 b-ID algorithms

page 12

Sascha Caron

slide15
The Silicon Track Trigger at DØ

First studies

using data

Using MC pdfs

preliminary

Jet data

Offline B-tagged data

preliminary

Likelihood shifted to

higher values due

to e.g. min bias effects

Max IP Significance

Likelihood

L2 data well correlated with offline data

-> proof of b-id principle -> Much more studies on their way

page 13

Sascha Caron

slide16
The Silicon Track Trigger at DØ

Summary

  • The STT is operating routinely and smooth
  • High Impact Parameter resolution
  • Data is understood
  • Very fast L2 b-id is (almost) implemented
  • We expect a high potential for
  • Z->bb and Higgs physics now and at L=200E30cm-2/s

Outlook

  • Implementation of new Layer 0 (r=22mm) into STT
  • -> further increase in precision and stability

page 14

Sascha Caron

ad