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ZEUS Global Tracking Trigger

This page is your portal to the exciting world of the GTT

What is the GTT?

The ZEUS GTT Barrel Algorithm integrates track information from the ZEUS central tracking detector (CTD) and micro vertex detector (MVD) to obtain a global picture of the track topology in the barrel region (-1.5 < eta < 1.5) of the ZEUS detector at the Second Level Trigger (SLT) stage.  Algorithm processing is performed on a farm of Linux PCs and, to avoid unacceptable deadtime in the ZEUS readout system, must be completed within the strict requirements of the ZEUS trigger system. The GTT Barrel Algorithm greatly improves the vertex resolution and the track finding efficiency of the ZEUS SLT while the mean event processing latency and throughput are well within the trigger requirements.
The barrel algorithm, using CTD only data, has been used in the SLT since 2004, currently MVD hits are being included.

The ZEUS GTT Forward Algorithm integrates track information from the ZEUS Micro Vertex Detector (MVD) and forward Straw Tube Tracker (STT) to provide a picture of the event topology in the forward  direction (1.5 < eta < 3) of the ZEUS detector at the SLT stage. This region is particularly challenging because of inhomogeneities in the solenoid magnetic field, and the high occupancies in the forward direction from beam gas interactions and secondary scatters with the ZEUS beampipe.  The Forward Algorithm is distinct from the GTT Barrel Algorithm,  but runs in parallel on the GTT CPU farm.
The forward algorithm is a planned addition to the GTT, it is not currently running.

How to maintain this web site

Any account which is a member of the w3gtt GID group can modify the GTT web site. If you are not a member, and should be, contact Ingo Martens. As ownership of modified files reverts back to the modifier's GID it is good practice to run ~/groupt.script before logging out to set w3gtt group ownership for all files. Ownership is, in anycase, reset automatically every eight hours by a cron job.

Work list

List of work to be done.

NIMA paper preparation

Where can I find more information?

ZEUS forum

The GTT development forum includes minutes from GTT meetings and additional relevant information since Jan/2003. The GTT status and news forum contains essentially no information and should not be used.

ZEMS

The GTT section contains presentations given at the biweekly meetings since Jun/2004. GTT related talks can also be found in the Trigger meeting section.

GTT poster

Dmitri's Power Point poster.

Obsolete home page

Pre ZEMS/Forum home page listing conference talks, ZEUS notes, talks from ZEUS Collaboration meetings, trigger meetings, MVD meetings, GTT meetings, modification log, list of runs used to produce conference plots. Needs merging into this web page

Modifications

Modifications to the online executable as a function of run number.

Related information

Non GTT information which is relevant.

GTT quantities used by the GSLT

To GSLT

Contains an description (definition, efficiencies, resolutions, etc.) of which GTT derived quantities are sent the GSLT trigger.

At GSLT

Describes which GTT quantities are used by which trigger at the GSLT.

Details

DQM

These pages describe Data Quality Monitoring.

DDL    

These pages describe GTT and MVD banks used (DDL = Data Definition Language)

Online

These pages contain descriptions of the online software, including the simulation system.

User pages

Bruce Straub's GTT page

Beam-gas rejection algorithm, instructions for running the GTT algorithm in an Orange job, various talks, ntuples for GTT studies

Mark Sutton's GTT page

Various talks, ZEUS notes, instructions on compiling with, and running the the GTT barrel algorithm zgana simulation

Constants

Web tool

To change the tracking constants used online. Read the help instructions before starting and note that definitions can be changed only by a browser running with a DESY IP address.
The new constants file (pfile.txt) is copied to its correct offline location (~gttdqm/calibration/) by a script (~gttdqm/cron/pfile/pfile.script) run every hour by k5crontab. The cron script also emails a notification that the constant file has changed.

CTD DQM

Link to the CTD DQM page where CTD associated constants are plotted (see history plots.)

How to test the GTT code in standalone

GTT analyse

c++ project to run and test the GTT algorithm in standalone

Where can I find the GTT Source Code?

The guidelines and rules explain how CVS is used to manage GTT sources. First time users should look at my first checkout

Barrel

Contains barrel algorithm and ZGANA source code

Online

Contains the used online barrel and forward source directories, plus process environment shell and simulation/testing source code.

Groups

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DESY