There is no independent experimental evidence for any of these particles.

There was no independent evidence to support the claim.

It is often possible, however (as in the insurance company examples), to get some independent evidence of effort or actions.

However no primary independent evidence exists to verify these claims.

There is no primary independent evidence to verify these claims.

According to at least some independent evidence, that is beginning to occur.

But there is no independent evidence to sustain those charges.

I've not yet been able to find rigorous independent evidence of this.

"Now we have independent evidence of its impact on health."

"What the prosecutors use must be independent and pre-existing evidence."