Detection and Characterization of the Temperate Super-Earth Ross 318 b

Ross~318 is an M3.5V red dwarf exhibiting significant magnetic activity and a stellar rotation period of \sim51.5\,d. In this work we present a systematic re-analysis of radial velocities (RV) from CARMENES and decade-long HIRES observations, integrated with TESS space-based photometry. We identify a terrestrial-mass planet, Ross~318\,b, with an orbital period P = (39.6299 \pm 0.29)\,d and a minimum mass M\sin i = (6.21 \pm 0.62)M_{\oplus}. The dynamical nature of the signal is confirmed by its temporal coherence over a 15-year baseline and its achromaticity between visible and near-infrared channels. TESS photometry from Sectors 18, 19, 24, and 25 (218.6\,d total baseline, 66\,983 cadences) reveals no transit at P = 39.63\,d (FAP > 10\%, BLS). An injection-and-recovery test demonstrates that a 2200\,ppm transit signal corresponding to a 1.74R_{\oplus} body would have been detected with Signal-to-Pink-Noise Ratio SPNR > 12, ruling out a transiting geometry with high confidence. The orbital inclination is constrained to i < 88.5^\circ. With an incident stellar flux S_{eff} \approx 0.58\,S_\oplus and bolometric luminosity L_* = (0.01478 \pm 0.00122)L_{\odot}, Ross~318\,b falls within the Conservative Habitable Zone, making it one of the most interesting temperate Super-Earths orbiting an M-dwarf.