The improvement of GstLAL's ranking statistics toward the fourth observing run

Given the upgraded sensitivity of the ground-based gravitational-wave (GW) detectors, the upcoming fourth observing run (O4) by the LIGO Scientific, Virgo, KAGRA Collaboration is expected to have more GW detections from compact binary systems than ever. During this exciting era of the GW astronomy, the improvement of GW detection pipelines plays a crucial role in further increasing GW detection rate. In this talk, we present the ongoing development for the GstLAL low-latency pipeline prepared for O4, focusing on the improvement for computing a likelihood ratio, with which to rank event's significance. Specifically, the major improvement is contributed by the removal of signal contamination, the new grouping scheme of a template bank, and the new signal model in SNR-chisq parameter space. As a result, we show the increase in the pipeline's search sensitivity by 10-20% in a simulated injection search.