RM-R1: Reward Modeling as Reasoning - Chen, Xiusi; Li, Gaotang; Wang, Ziqi; Jin, Bowen; Qian, Cheng; Wang, Yu; WANG, Hongru; Zhang, Yu; Zhang, Denghui; Zhang, Tong; Tong, Hanghang; Ji, Heng (International Conference on Learning Representations, 2026)