Title: STAR High Level Trigger

Speaker: Hongwei Ke (BNL)

Abstract: We implemented a High-Level Trigger (HLT) system for the STAR experiment to better utilize the luminosity delivered by RHIC. By reconstructing tracks and assembling data from multiple detectors, STAR HLT can select events of great physics interests online, which will reduce the data volume to tape, speed up offline physics analysis and provide vital online monitoring information. In the past a few years, a series of important physics achievements and programs of STAR have benefited from HLT, including the discovery of anti-alpha particles, the first J/\Psi elliptic flow measurement, the Beam Energy Scan program phase I and more recently the STAR heavy flavor tracker and muon telescope detector program. Currently, STAR HLT has 10 times of the computing resources than we had in 2012, which contains about 1200 CPU cores and 45 Xeon Phi (KNC) coprocessors. In this talk, I will discuss the development of STAR HLT, lessons we learned of using such a heterogeneous system and most importantly the physics opportunities opened with these resources.