What does anneal mean in the context of machine learning?
Annealing is short for simulated annealing. Simulated annealing is the process of slowly decreasing the probability of accepting worse solutions as the solution space is explored. Over the course of the experiment, γ value was slowly lowered to balance exploration and exploitation. γ is a machine learning hyperparameter so any hyperparameter search method would work (e.g., manually selection or cross-validation).