The GAUSS Project

Welcome to the GAUSS project website

Gauss is the simulation program of the LHCb experiment, based on the Gaudi framework and on the LHCbSys classes.

Announcements

To have access to all the available versions, please follow this link.

This link points to the latest doxygen available for this project.

Gauss mimicks what will happen in LHCb to allow understanding of its experimental conditions and its performance. It integrates two independent phases:

  1. A Generator Phase consisting of the generation of the p-p collisions and the decay of the particles produced
  2. A Simulation Phase consisting in the tracking of the particles in the detector and simulating the physics processes occuring in the experimental setup
Gauss is interfaced to various specialized packages available in the Physics community for the Generator phase (e.g. EvtGen for b-decays) and makes use of the Geant4 toolkit for the Simulation phase. For more specific information on each of the phases and the libraries used follow the links provided above.

Gauss is structured as a CMT project containing an application package, also called Gauss, and a set of packages (component and linker both) specific to the physics simulation of the experiment and constituting the whole of the application. The application package provides the job options and main program for running the Gauss application. The default options are the configuration used in Production but for those specific to a given job (i.e. number of events, event type). Options for some different configuration of the application are provided. The configuration for different event types are provided in the DecFiles configuration package.

Productions

The most recent production is currently in progress to generate MC events for the 2011 data taking. Almost all events are being produced with conditions as similar as possible to the year. Some events will be produced with conditions simular to special data taking as for the 1380 GeV beam energy.

Development productions were done in 2011. They are referred in the book-keeping as 2011. They should NOT be used for physics studies.

The list of event types available for production and their documentaion can be found in the DecFiles web pages.

The type of files that can be produced for simulated data can be found in this page

MC11a

The Gauss version used for MC11 so far is v41r1, while DecFiles v25r0 to v25r3 have been used.

Two main sets of Simulation Conditions have been used

The whole list of Simulation Conditions and Processing pass are available at this page where the available steps are also listed. A detailed explanation is provided as reference to the models that can be used to submit production requests. The data is available from the book-keeping under MC11a and underlying Simulation Conditions and Processing Pass folders.

The generator settings (cross sections, B fractions, etc.) used for the production will soon be made available. For the moment refer to the page for MC09 as only slight changes were introduced.

Statistics for all data types is been produced for both the generator and simulation phase using counters printed in each Gauss job.

Documentation on the counters and on the script to produce the generator and simulation statistics:

Older Productions

Older productions have been done with frozen conditions. This data is now deprecated and people should move to use MC11 for their studies, requesting specific event type to be produced if needed.

MC10 was done to simulate events for the 2010 data taking. Samples are still available from the book-keeping and can still be used for the analysis of last year data. It was done with Gauss v39r0 to v39r4 and DecFiles v23r2 to v23r11.

MC09 was done starting with Gauss v37r2 to v37r7. Some of the data can be still be found in the bookkeeping under the Sim03-Rec02 configuration and higher. The data consisted of 10 billions minimum bias without MCtruth and 10 million Miminum bias and some signal samples.

Older DC06 production for physics has been done starting with Gauss v24r8. DC06 data has already been removed or will be removed shortly.

The generator settings (cross sections, B fractions, etc.) used for the production are available from

Statistics for all data types have been produced for both the generator and simulation phase using counters printed in each Gauss job for DC06 and MC09.

Reference documentation

Documentation for available releases can be found by following the links at the top of this page. The environment for working with a given version of Gauss should be set up with the SetupProject Gauss script.

Additional Documentation

Development and future releases

Refer to the Gauss twiki page for details on version number, release schedule and contents. A list of work in progress or foreseen is available from the Gauss development twiki page.
Note that:

Supported platforms and compilers

Source code and binaries for supported platforms are available on disk (in AFS directory /afs/cern.ch/lhcb/software/releases - $LHCBRELEASES), and in the form of tar file distribution kits. The following platform+compiler combinations are supported:

More information can be found in the LHCb Supported Platforms TWiki pages

Reporting bugs

You can report bugs or view bug histories via the LHCb physics software Savannah portal (Simulation Category).

Project History

The history of dependencies and included packages can be viewed for any tagged version (including the ones that have been removed) from the CVS web interface. Check for the versions with the relevant CVS tags. For project dependencies see the GAUSS project.csh file. For the versions of the packages included in the GAUSS project see the GaussSys requirements file. Some more dependencies can be read from the Sim/Gauss requirements file.