No Evidence for Second-scale Periodicity in FRB 20201124A from 2021 April to June FAST Observations

Fast radio bursts (FRBs) are bright and short radio flashes of cosmological origin. Although a great number of FRBs have been detected in the last two decades, their progenitors and the physical processes that create them are unknown. In recent years, magnetars have been proposed as one of the leading progenitor candidates. A striking feature that can hint at such a magnetar origin is second-scale periodicity. In this paper, we define a robust procedure to search for such periodicity and estimate the significance of its results. We search for such periodicity in the bursts of FRB 20201124A, observed by the Five-hundred-meter Aperture Spherical Telescope between 2021 April and June. Our analysis does not find any significant periodicity. We discuss the differences between our nondetection and the ∼1.7 s periodicity claim by C. Du et al.