Improved binary black hole searches through better discrimination against noise transients

Short-duration noise transients in LIGO and Virgo detectors significantly affect the search sensitivity of compact binary coalescence (CBC) signals, especially in the high-mass region. In a previous work by the authors [P. Joshi, Phys. Rev. D 103, 044035 (2021)PRVDAQ2470-001010.1103/PhysRevD.103.044035], a χ2 statistic was proposed to distinguish them, when modeled as sine-Gaussians, from nonspinning CBCs. The present work is an extension where we demonstrate the better noise-discrimination of an improved χ2 statistic - called the optimized sine-Gaussian χ2 - in real LIGO data. The extension includes accounting for the initial phase of the noise transients and use of a well-informed choice of sine-Gaussian basis vectors selected to discern how CBC signals and some of the most worrisome noise transients project differently on them [S. Choudhary et al., Phys. Rev. D 107, 024030 (2023)PRVDAQ2470-001010.1103/PhysRevD.107.024030]. To demonstrate this improvement, we use data with blip glitches from the third observational run (O3) of LIGO-Hanford and LIGO-Livingston detectors. Blips are a type of short-duration non-Gaussian noise disturbance known to adversely affect high-mass CBC searches. For CBCs, spin-aligned binary black hole signals were simulated using the imrphenompv2 waveform and injected into real LIGO data from the same run. We show that in comparison to the sine-Gaussian χ2, the optimized sine-Gaussian χ2 improves the overall true positive rate by around 6% in a lower-mass bin (m1,m2 [20,40]M) and by more than 3% in a higher-mass bin (m1,m2 [60,80]M). On the other hand, we see a larger improvement - of more than 20% - in both mass bins in comparison to the traditional χ2.