That's a loaded question. It is possible, but it is an enormously difficult task. As a very general and broad principle - the evidence must be of such tremendous significance to the case that it undermines a court's confidence in the validity of the verdict. In other words, if the jury had heard this evidence, is it likely they would have delivered a different verdict.
This is a grossly general statement, but should give you some context. It is profoundly difficult for a convicted person to succeed in this effort on his/her own without the assistance of counsel.
I agree completely with the attorney above. This is a very, very complex area of law and you should consult with an attorney who specializes in criminal appeals and habeas law. A court may not even permit you to introduce "newly discovered evidence" if it should have or could have been discovered earlier, during the trial and/or direct appeal. For more information you should contact the Prison Law Office or the California Appellate Project [CAP] for your area.