English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In LHC Run 3, ALICE will increase the data taking rate significantly, from anapproximately 1 kHz trigger readout in minimum-bias Pb--Pb collisions to a 50kHz continuous readout rate. The reconstruction strategy of the online-offlinecomputing upgrade foresees a synchronous online reconstruction stage duringdata taking, which generates the detector calibration, and a posteriorcalibrated asynchronous reconstruction stage. The huge amount of data requiresa significant compression in order to store all recorded events. The aim is afactor 20 compression of the TPC data, which is one of the main challengesduring synchronous reconstruction. In addition, the reconstruction will runonline, processing 50 times more collisions than at present, yielding resultscomparable to current offline reconstruction. These requirements pose newchallenges for the tracking, including the continuous TPC readout, moreoverlapping collisions, no a priori knowledge of the primary vertex positionand of location-dependent calibration during the synchronous phase,identification of low-momentum looping tracks, and a distorted refit to improvetrack model entropy coding. At the 2018 workshop, the TPC tracking for Run 3was presented, which matches the physics performance of the Run 2 offlinetracking. It leverages the potential of hardware accelerators via the OpenCLand CUDA APIs in a shared source code for CPUs and GPUs for both reconstructionstages. Porting more reconstruction steps like the remainder of the TPCreconstruction and tracking for other detectors to GPU will shift the computingbalance from traditional processors towards GPUs. These proceedings focus onthe global tracking strategy, including the ITS and TRD detectors, offloadingmore reconstruction steps onto GPU, and the approaches taken to achieve thenecessary data compression.

Global Track Reconstruction and Data Compression Strategy in ALICE for LHC Run 3