You are a moron if you believe they exist anywhere as matter. Technically they (i.e. mirror image matter/antimatter pairs) cancel each other out. They only exist as probabilities. They don't exist in another dimension because they would annihilate it other if they did.Oh, they exist. Just not in our dimension or universe. We just don’t have the knowledge or equipment yet to find where they are when we can’t see them and why we can’t see them. Scientists can’t even explain what is going on. God could but we aren’t ready to understand.