LHCb

The LHCb (standing for "Large Hadron Collider beauty") experiment is one of the particle physics detector experiments collecting data at the Large Hadron Collider accelerator at CERN. LHCb is a specialized b-physics experiment, that is measuring the parameters of CP violation in the interactions of b-hadrons (heavy particles containing a bottom quark). Such studies can help to explain the Matter-Antimatter asymmetry of the Universe.

The detector is also able to perform measurements of production cross sections and electroweak physics in the forward region. Approximately 840 people from 60 scientific institutes, representing 16 countries, form the collaboration which built and operate the detector.. The experiment is located at point 8 on the LHC tunnel close to Ferney-Voltaire, France just over the border from Geneva. The (small) MoEDAL experiment shares the same cavern.

Bit Preservation: 

Data and MC samples are stored on tape and on disk. Two copies of raw data on tape ; 1 copy on tape of full reconstructed data (FULL.DST, which contains also raw data) ;4 copies of stripped data (DST) on disk for the last (N) reprocessing. Two copies for the N-1 reprocessing. One archive replica on tape.

Data: 

For the long term future, LHCb plans to preserve only a legacy version of data and MC samples. Run 1 legacy data: 1.5 PB (raw), 4 PB FULL.DST, 1.5 stripped DST. Run 1 legacy MC : 0.8 PB DST.

Open data: LHCb plans to make 50% of analysis level data (DST) public after 5 years, 100% public 10 years after it was taken.  The data will be made public via the Open Data portal (http://opendata.cern.ch/)

Samples for educational purposes are already public for the International Masterclass Program and accessible also via the Open Data portal (For Education area).

Documentation: 

Data: dedicated webpages for data and MC samples, with details about all processing steps.

Software : twiki pages with software tutorials, mailing-lists.

Documentation to access and analyse masterclasses samples is available on LHCb webpage and on the OpenData portal.

Software: 

Software is organised as hierarchy of projects containing packages, each of which contains some c++ or python code. Three projects for the framework (Gaudi, LHCb, Phys), several “component” projects for algorithms (e.g. Lbcom, Rec, Hlt, Analysis), one project per application containing the application configuration (e.g. Brunel, Moore, DaVinci).

Software repository: SVN.

Open access: once data will be made public, software to work with DST samples will be released with the necessary documentation.

A virtual machine image of LHCb computing environment allows to access and analyse the public samples available on the Open Data portal

Use Cases: 

New analysis on legacy data ; anaysis reproduction ; outreach and education.

Audience: 

LHCb collaboration ; physicists outside the collaboration ; general public.

Value: 

LHCb complementary to other LHC experiments.

Uniqueness: 

Unique samples of pp an HI collisions collected in the forward region.

Resources: 

Dedicated working group within LHCb computing group.

Status: 

Legacy software and data releases defined. Development of a long-term future validation framework ongoing. Masterclasses samples and analysis software available via the Open Data portal. Collaboration with CERN IT and other LHC experiments for the development of an analysis preservation framework.

Issues: 

Main issue is manpower.

Outlook: 

Collaboration with CERN IT and other LHC experiments on the Open Data portal and the analysis preservation framewok.

Enrich the Open Data portal with additional masterclass exercise and real LHCb analysis. Exploit VM technology to distribute LHC computing environment. 

Host Lab: 

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