First experiences with the LHCb heterogeneous software trigger

TL;DR

This paper reports on the initial implementation and results of the LHCb's fully software-based, heterogeneous trigger system utilizing GPUs and CPUs for real-time data processing and analysis at the LHC.

Contribution

It introduces the first operational deployment of a heterogeneous software trigger system at LHCb, enabling online reconstruction, calibration, and physics analysis.

Findings

Successful online data reconstruction and calibration

First physics results from real-time analysis

Demonstration of GPU and CPU integration in trigger system

Abstract

Since 2022, the LHCb detector has been taking both proton-proton and lead-ion data at the LHC collision rate using a fully software-based trigger. This has been implemented on GPUs at its first stage and CPUs at its second. The setup allows for reconstruction, alignment, calibration and selections to be performed online -- known as the real time analysis paradigm. As well as this, physics analyses are performed using the output of online reconstruction with early results shown using data taken in 2022.