Description
We present a comprehensive spectral and timing analysis of the newly discovered black hole transient Swift J1727.8-1613, based on broadband (1-150 keV) observations from Insight-HXMT during its 2023 outburst. Using the flexible, energy-conserving SSsed model, we identify the presence of both thermal and non-thermal Comptonization components in the hard component dominated state. We track the evolution of the truncated accretion disc radius, $R_{\rm tr}$, which decreases from 45 $R_{\rm g}$ to 9 $R_{\rm g}$, consistent with the transition from the hard to the intermediate state. Additionally, we explore the correlation between $R_{\rm cor}$ and the centroid frequency of quasi-periodic oscillations (QPOs; $\nu_{\rm c}$) to test the hot flow Lense-Thirring (LT) precession model. The overall trend is consistent with LT precession predictions, showing a decrease in the scale height-to-radius ratio ($h/r$) as the source evolves. However, deviations in the $R_{\rm cor}$-$\nu_{\rm c}$ relation imply additional contributing factors, such as escaped jet power, flipped inner disc, and variations in the hot flow height.
