What is a good research experience
What kind of research experience is a good or satisfactory research experience for grad school admissions?
How do you set the threshold?

There is no threshold.  Instead, graduate admissions committees judge research experience on a continuum.  At one end are things that hardly count at all (e.g., independent textbook study described as research).  At the other end are extremely impressive publications.  Most undergraduate research is somewhere in the middle, and how meaningful it is can be difficult to judge.  To help the committee, you need to explain what you did, why it is interesting, what your contributions were, and perhaps what you learned from it or got out of it (especially if it didn't lead to a publication in a high-quality journal or conference).  It's also important to have a letter of recommendation that addresses this research, to evaluate your contributions.  If you just mention a paper on your CV, without giving this sort of background information about it, then it probably won't help your application much.

Will I get an edge over other people with no publications or who does not want to publish at such places?

It's hard to predict.  Nobody's going to be counting papers or setting thresholds for impact factor.  Instead, the committee will be looking for two key things:

Have you demonstrated the ability to do research?  (Some people get wonderful grades but do not succeed at research.)

Do you have enough experience to know what you are getting into in graduate school?  (Some people think they want to do research, but when they discover what research really involves they change their minds.)


Instead of worrying about thresholds and quantities, I'd suggest focusing on making sure your application satisfies these criteria.