From European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN]: “Bringing new life to ATLAS data” 


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From European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN]

22 October, 2021

Iconic view of the European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN] ATLAS detector

The ATLAS collaboration is breathing new life into its LHC Run 2 dataset recorded from 2015 to 2018. Physicists will be reprocessing the entire dataset – nearly 18 PB of collision data – using an updated version of the ATLAS offline analysis software (Athena). Not only will this improve ATLAS physics measurements and searches, it will also position the collaboration well for the upcoming challenges of Run 3 and beyond.

Athena converts raw signals recorded by the ATLAS experiment into more simplified datasets for physicists to study. Its new-and-improved version has been in development for several years and includes multi-threading capabilities, more complex physics-analysis functions and improved memory consumption.

“Our aim was to significantly reduce the amount of memory needed to run the software, widen the types of physics analyses it could do and – most critically – allow current and future ATLAS datasets to be analysed together,” says Zach Marshall, ATLAS Computing Coordinator. “These improvements are a key part of our preparations for future high-intensity operations of the LHC – in particular the High-Luminosity LHC (HL-LHC) run beginning around 2028, which will see ATLAS’s computing resources in extremely high demand.”

This latest version of Athena already makes good headway in reducing the computing resources required for data analysis. For example, the computationally intensive job of taking individual signals from the inner detector and chaining them together to form particle tracks is now two to four times faster. Less disk space is needed to store the results and overall the software runs more smoothly.

The software improvements also feature new ways for physicists to study their data. For example, researchers will now, by default, be able to look for tracks that originate away from the collision point. These could be signatures of particles with long lifetimes and may lead to evidence of exciting beyond-the-Standard-Model physics processes. While such searches were possible with the earlier version of the ATLAS software, the heavy computing resources they required meant they could not always be carried out.

Finally, physicists have also made improvements to the databases containing all of the time-dependent status information of the detector components. These databases – on which Athena runs – now incorporate an improved understanding of the detector’s operation during Run 2. “Every data-taking period is an opportunity for us to learn more about the detector and its subsystems,” says Song-Ming Wang, ATLAS Data Preparation Coordinator. “Revisiting these databases with the benefit of hindsight will allow us to provide even better performance.”

With the new Athena software now up and running, researchers have set out to reprocess the entire Run 2 dataset. This will take several months, as the dataset is quite substantial.

The expected results will be well worth this effort: ATLAS will have a significantly improved dataset that will allow for crisper measurements, more powerful searches and simpler combinations of past and future data.

See the full article here.


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THE FOUR MAJOR PROJECT COLLABORATIONS

ATLAS
European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire](CH) ATLAS.

ALICE
European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire](CH) ALICE .

CMS
European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) CMS.

LHCb
European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) LHCb.

LHC

European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire(CH) map.

CERN LHC underground tunnel and tube.

CERN SixTrack LHC particles.

OTHER PROJECTS AT CERN

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU)[CERN] AEGIS.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN]ALPHA Antimatter Factory.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] ALPHA-g Detector.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] AMS.

</a European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] ASACUSA.

CERN ATRAP.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] Antiproton Decelerator.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] AWAKE.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] BASE: Baryon Antibaryon Symmetry Experiment.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] BASE experiment.

</a European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] CAST Axion Solar Telescope.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] CLOUD.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] COMPASS.

CERN CRIS experiment

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN]DIRAC.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] FASER experiment schematic.
CERN FASER is designed to study the interactions of high-energy neutrinos and search for new as-yet-undiscovered light and weakly interacting particles. Such particles are dominantly produced along the beam collision axis and may be long-lived particles, travelling hundreds of metres before decaying. The existence of such new particles is predicted by many models beyond the Standard Model that attempt to solve some of the biggest puzzles in physics, such as the nature of dark matter and the origin of neutrino masses.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] GBAR.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN]ISOLDE Looking down into the ISOLDE experimental hall..

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] LHCf.

CERN-The MoEDAL experiment- a new light on the high-energy frontier.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] NA62.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] NA64..

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] NTOF.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN]TOTEM.

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] UA9.

CERN The SPS’s new RF system. Image: CERN

European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire)(EU) [CERN] Proto Dune.