o status update for the low momentum TF - F2F oct 12 Jakob - - PowerPoint PPT Presentation

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• status update for the low momentum TF - F2F
• ct 12

Jakob Lettenbichler, Rudolf Fr¨ uhwirth

Institute of High Energy Physics Austrian Academy of Sciences

October 29, 2012

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 1 HEPHY Wien & BELLE Collaboration

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The silicon vertex detector of Belle II

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 2 HEPHY Wien & BELLE Collaboration

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Before we start...

Definitions

sector: subunit of a sensor friends: two compatible sectors combined segment: two compatible hits combined neighbours (NBs): two compatible segments combined efficiency: number of TCs recovered / number of tracks got by mcTrackfinder (mcTF records track, if at least 3 hits found within SVD or filters by momentum) track is recovered, when:

at least 3 hits of track has been found again by any single TC more than 70% of hits are of assigned track

clean TC has no foreign hits contaminated TC carries foreign hits

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 3 HEPHY Wien & BELLE Collaboration

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Overlapping sensors for low momentum track finding

aspects relevant for SVD-only tracking

slanted sensors with overlapping regions are huge advantage compared to SVD2-design (next to fully usable 4 layers)

• verlapping regions are a bonus, but not essentially needed

low momentum tracks need 3 hits for reconstruction, therefore:

• verlapping sensors strongly appreciated for layer 3 and 4

(one extra hit there gives opportunity to search for tracks not reaching layer 5&6)

• verlapping sensors are a bonus, but not essentially needed

for layer 5 and 6 (here we have already at least 3 hits)

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 4 HEPHY Wien & BELLE Collaboration

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Approach for reducing combinatorics

Sector of interest Friends (compatible Sectors)

distance angle zigg- zagg

O L Segment finder - 2-hit filter filters by distance, min&max, including virtual Segment

L Cellular Automaton

evolving states, includes TC-collector

Hopfield Network

uses QI's to find best subset among overlapping TC's

Clean TC's

Kalman filter

calculates QI's O L Post 4-hit filter filters by zigZag, ΔpT, ... O L Neighbour finder - 3-hit filter filters by angle and Δ-distance min&max, pT O L Sector setup - 1-hit filter filters by set of compatible sectors, allows momentum dependent setups

• The arrows represent a

schematic interpretation of the possible number of combinations

• f hits at that point
• Filters marked with an O use

external information generated by simulation

• Steps marked with an L cycle

through several passes

Schematic view of the low momentum track finder in Belle II

Unsorted hits from tracks, background, ghost coming from an event

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 5 HEPHY Wien & BELLE Collaboration

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Alpha release

changes since July:

multipass without hit-removal to cover broad momentum ranges within one event Kalman filter finally implemented first SVD-only BG-check for pGun and evtGen-events finished cleaning of code external analysis tool works (not released) (tons of) bugfixes

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 6 HEPHY Wien & BELLE Collaboration

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Test setup

settings

pGun: 1T/10T pions with 45MeV/c ≤ pT ≤ 250MeV/c with and without BGmixer (see Peters talk) TF: minimal filters (dist3D, angles3D, deltapT, ziggzagg) with and without KF+NN evtGen: with and without BG. Efficiencies calculated only for 50-200 MeV/c pT all runs: SVD only 3 pass: low: 3 layers, 45MeV/c ≤ pT ≤ 80MeV/c, std: 4 layers, 75MeV/c ≤ pT ≤ 175MeV/c, high: 4 layers, 140MeV/c ≤ pT ≤ 1100MeV/c 16➦ ≤ θ ≤ 151➦ 6 sectors per layer - u-boundaries (normed to sensor size): 0, 0.5, 1. v-boundaries: 0, 0.33, 0.67, 1

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 7 HEPHY Wien & BELLE Collaboration

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Preliminary results - september 2012

10 20 30 40 50 60 70 80 90 100 40 60 100 250 500 1000 efficiency in % transverse momentum [MeV/c] 3-pass-efficiency for single/10T pions depending on momentum range 1T 10T w/o Hopfield 10T w Hopfield

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 8 HEPHY Wien & BELLE Collaboration

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Preliminary results - F2F oct 2012

10 20 30 40 50 60 70 80 90 100 40 6075 100 250 500 efficiency in % transverse momentum [MeV/c] 3-pass-efficiency for single/10T pions depending on momentum range 1T wNN 1T w/oNN 10T wNN 10T wNNwBG 10T w/oNN

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 9 HEPHY Wien & BELLE Collaboration

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Preliminary results - F2F oct 2012 closeup

70 75 80 85 90 95 100 40 50 60 75 100 250 efficiency in % transverse momentum [MeV/c] 3-pass-efficiency for single/10T pions depending on momentum range 1T wNN 1T w/oNN 10T wNN 10T wNNwBG 10T w/oNN

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 10 HEPHY Wien & BELLE Collaboration

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evtGen

ghost rate not easy to calculate because of limited momentum range considered by efficiency w/o BG: 84.8% within 50-200 MeV/c pT with BG: 83.3% within same momentum range 10T with KF+NN: 400ms/event (some single events take several seconds, combinatorics in KF too) tested on a 4 yeaar old C2D with 3GHz, singlethreaded evtGen: w/o BG: 1100ms*, withBG: 1200ms* (*: tested on 7 year old C1D with 1,66GHz, therefore not comparable)

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 11 HEPHY Wien & BELLE Collaboration

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Time Consumption

1T w/o KF+NN: 1ms/event 1T with KF+NN: 15ms/event (KF is slow) 10T w/o KF+NN: 15ms/event (combinatorics takes effect) 10T with KF+NN: 400ms/event (some single events take several seconds, combinatorics in KF too) tested on a 4 yeaar old C2D with 3GHz, singlethreaded evtGen: w/o BG: 1100ms*, withBG: 1200ms* (*: tested on 7 year old C1D with 1,66GHz, therefore not comparable)

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 12 HEPHY Wien & BELLE Collaboration

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Outlook

ToDo

improve analysis capabilities (long term: auto-test with pretty plots) checking performance under realistic event- and background conditions (next goal: PXD) support curling tracks A.S.A.P (after BG-check)

• ptimize sectorMaps for each pass (long term task)

bugfixing developing online version (project starts 2013Q1)

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 13 HEPHY Wien & BELLE Collaboration

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that’s all, folks!

Any suggestions, ideas or requests? Jakob.Lettenbichler@oeaw.ac.at

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 14 HEPHY Wien & BELLE Collaboration

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Results of CHEP2012

Setting

Low: pT = 60 – 70MeV/c, 3 layers (w/o PXD) Low: pT = 60 – 70MeV/c, 5 layers (with PXD) High: pT = 70 – 100MeV/c, 4 layers (w/o PXD) High: pT = 70 – 100MeV/c, 6 layers (with PXD)

pT range # of layers # of tracks results post TCC clean cont. lost rectot Low 3 10 000 88.9% 0.48% 10.7% 89.3% 20 000 88.2% 1.1% 10.8% 89.2% Low 5 10 000 99.6% 0.1% 0.3% 99.7% 20 000 99.1% 0.3% 0.6% 99.4% High 4 10 000 99.6% 0.1% 0.4% 99.6% 20 000 99.5% 0.1% 0.4% 99.6% High 6 10 000 99.6% 0.1% 0.3% 99.7% 20 000 99.4% 0.2% 0.4% 99.6%

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 15 HEPHY Wien & BELLE Collaboration

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Features

some highlights

input: PXD/SVD-Clusters,

• utput: GFTrackCand (same as McTrackFinder, be careful

when using both) recovery strongly depends on sector maps (XML-Files), which cover pT range of ∼ 50 − 1000MeV/c Sector maps for low (50-75MeV/c), med(70-170MeV/c) and high (150-1000MeV/c) momenta available (SVD-only, PXD-next week)

Jakob Lettenbichler, Rudolf Fr¨ uhwirth 16 HEPHY Wien & BELLE Collaboration