--
KathrynGrimm - 2016-11-29
Notes on Statistics
NotesOnStatistics
Slides from Summer Lectures:
https://indico.cern.ch/event/634036/
Notes on Vertex Reconstruction
Track requirements for vertex reconstruction:
http://acode-browser2.usatlas.bnl.gov/lxr-rel20/source/atlas/InnerDetector/InDetExample/InDetRecExample/python/ConfiguredVertexingCuts.py#0020
Seeding
When the Beam Spot is available then vertices are seeded using the
ZScanSeedFinder
. When no beam spot is available then the
CrossDistancesSeedFinder
is used. This is configured with the python flag
"InDetFlags.doPrimaryVertex3DFinding()". If this is true, then the Cross Distances seed finder is setup, otherwise, the ZScan seedfinder is used.
This is configured in the job option:
https://svnweb.cern.ch/trac/atlasoff/browser/InnerDetector/InDetExample/InDetRecExample/trunk/share/InDetRecLoadTools.py#L1410
The doPrimaryVertex3DFinding() flag itself is configured here:
http://acode-browser.usatlas.bnl.gov/lxr/source/atlas/InnerDetector/InDetExample/InDetRecExample/python/InDetJobProperties.py
The 3DFinding flag is true by default, but if the flag
InDetFlags.useBeamConstraint() is true, doPrimaryVertex3DFinding() is changed to false.
The useBeamConstraint() flag, in turn, is true by default, but set to false for certain processing streams in this script (it is set to false for the Express stream, for instance).
The vertex "finding" configuration:
In pp running multiple vertices are allowed. All tracks are used to find as many vertex candidates as possible. In Heavy Ion running only one vertex is allowed-- a single candidate is formed from all tracks.
In the finder tool the beam spot constraint is applied:
https://svnweb.cern.ch/trac/atlasoff/browser/InnerDetector/InDetRecTools/InDetPriVxFinderTool/tags/InDetPriVxFinderTool-02-01-05/src/InDetIterativePriVxFinderTool.cxx#L384
Fitting
The standard proton-proton PV reconstruction uses the
Adaptive Vertex Fitter
It is a full Kalman filter with re-weighting. It gives high precision and high resolution, especially at low number of tracks. Requires more CPU time than e.g. the Heavy Ion Fast Billoir fitter. May not converge on a vertex with few thousands tracks within allowed number of iterations. (Info from kirill)
For HI running the
FastBilloir
fitter is used. "Moderate resolution at low number of tracks,
linearization assumption applied on trajectories, very fast."
The formation of a single vertex candidate can happen via two
methods:
Heavy Ion uses:
Chi2Method=1: All tracks incompatible with initial seed are
rejected, the remaining tracks are fitted to a single vertex candidate,
this candidate is returned to the user.
Proton Proton uses:
Chi2Method=2: Tracks are removed one by one starting
from the least compatible one. At each iteration the vertex candidate
is re-fit and track compatibility is re-evaluated.
The Vertex Container
Relevant vertex quantities:
root [4]
CollectionTree->Scan("PrimaryVerticesAux.x[0]:PrimaryVerticesAux.covariance[0][0]:PrimaryVerticesAux.numberDoF[0]:PrimaryVerticesAux.vertexType[0]")
Vertex Types are defined here:
https://svnweb.cern.ch/trac/atlasoff/browser/Tracking/TrkEvent/TrkEventPrimitives/trunk/TrkEventPrimitives/VertexType.h
JIRA Tickets
High HT Events with Unmerged Nearby PVs:
https://its.cern.ch/jira/browse/ATLIDTRKCP-87
Size-Reduced AODs:
https://its.cern.ch/jira/browse/DATREP-80
Monitoring and Validation Software
Graham's updated tool:
https://svnweb.cern.ch/trac/atlasoff/browser/InnerDetector/InDetValidation/InDetVertexValidation
InDetGlobalMonitoring/InDetGlobalPrimaryVertexMonTool
https://svnweb.cern.ch/trac/atlasoff/browser/InnerDetector/InDetMonitoring/InDetGlobalMonitoring/trunk/src/InDetGlobalPrimaryVertexMonTool.cxx
=
Used in:
https://svnweb.cern.ch/trac/atlasoff/browser/InnerDetector/InDetExample/InDetRecExample/trunk/share/InDetMonitoringGlobal.py#L143
Presentations on the Split Vertex Method from Sarah Boutle:
26, Sept 2014
https://indico.cern.ch/event/295469/contribution/0/attachments/553859/763088/splitvertex_250914.pdf
22 Jan:
https://indico.cern.ch/event/366773/contribution/0/attachments/728989/1000269/splitvertex_220115.pdf
9 April:
https://indico.cern.ch/event/366784/contribution/0/attachments/729012/1000295/splitvertex_090415.pdf
23 April
https://indico.cern.ch/event/366786/contribution/1/attachments/729016/1000299/splitvertex_230415.pdf
8 May
https://indico.cern.ch/event/393249/contribution/7/attachments/786887/1078633/splitvertex_IDTP_080515.pdf
Sample dependence:
https://indico.cern.ch/event/366788/contribution/1/attachments/729020/1000303/splitvertex_070515.pdf
Information on Upgrade Tracking Studies
Vertex ideas from Dave June 2017:
https://indico.cern.ch/event/644782/contributions/2617854/attachments/1473267/2280561/UpgradeVertexIdeas_07Jun2017.pdf
Vertex Talk at XXIX IUPAP Conference on Computational Physics, Paris, France, 9 - 13 Jul 2017
https://cds.cern.ch/record/2273572/files/ATL-COM-SOFT-2017-038.pdf
Timing Detector:
https://indico.cern.ch/event/612694/contributions/2469924/attachments/1410303/2156813/physcisupgrade_cern_Feb9.pdf
https://indico.cern.ch/event/624321/contributions/2625309/attachments/1476059/2286741/HGTD_June_Ariel_v6.pdf
ITK Layout Task Force Document:
https://cds.cern.ch/record/2239573/files/ATL-COM-UPGRADE-2016-042.pdf
Strip TDR:
https://cds.cern.ch/record/2239048/files/ATL-COM-UPGRADE-2016-040.pdf
Examples for html:
√s= 8
TeV
21< μ <23 .
Position ((a) x
L, (c) y
L, (e) z
L) and size ((b) σ
x, (d) σ
y, (f) σ
z)
Z→ μμ p
T>15
GeV