I don't know what to call the realization of an absence (other than a realization), but I wouldn't call it "an experience" because it didn't occur in time and there was no felt kind of happening. There was no beginning or ending of anything. The body/mind suddenly "saw" or "realized" that the idea and/or sense of selfhood was no longer there. It had somehow disappeared/collapsed/evaporated. Only in the ABSENCE of that idea did it become obvious that there had NEVER been a self in any sense and that THIS, undivided, is all there is.
Oddly enough, for at least two hours prior to realizing what was absent (the usual idea of selfhood), there had been a vague sense of something missing, and at a particular moment it suddenly became obvious what was missing. This realization, or seeing, or whatever you want to call it, didn't trigger any euphoria or elation. It was a rather down-to-earth matter-of-fact kind of event followed by a certain degree of surprise. Nothing changed; there was simply the recognition that selfhood had been an idea, only; it was an idea that had no reality; and the idea was now absent.
Oddly enough, for at least two hours prior to realizing what was absent (the usual idea of selfhood), there had been a vague sense of something missing, and at a particular moment it suddenly became obvious what was missing. This realization, or seeing, or whatever you want to call it, didn't trigger any euphoria or elation. It was a rather down-to-earth matter-of-fact kind of event followed by a certain degree of surprise. Nothing changed; there was simply the recognition that selfhood had been an idea, only; it was an idea that had no reality; and the idea was now absent.