I have visualized a dataset in 2D after employing PCA. As 2D visualization shows in figure, there is a good separation between points (A, B). Now, I want to use a metric which can separate these points (between these 2 PC components not in main dataset) too. I mean have separation between these PCA components without visualization. I used some clustering methods but they raise false positives. I mean they miss cluster many points.
Also, as shown in histogram there is a gap between points A,B. Does this help in devising any metric?
I will be so grateful if you can introduce me any method and algorithm to be able to do separation between A and B.