GPUs for fast triggering and pattern matching at the CERN experiment NA62

In rare decays experiments an effective trigger is crucial to reduce both the quantity of data written on tape and the bandwidth requirements for the DAQ (Data Acquisition) system. A multilevel architecture is commonly used to achieve a higher reduction factor, exploiting dedicated custom hardware and flexible software in standard computers. In this paper we discuss the possibility to use commercial video card processors (GPU) to build a fast and effective trigger system, both at hardware and software level. The case of fast pattern matching in the RICH detector of the NA62 experiment at CERN aiming at measuring the Branching Ratio of the ultra rare decay K + → π + ν ν ¯ is considered as use case although the versatility and the customizability of this approach easily allow exporting the concept to different contexts.