That question did spawn from though experiments about what kind of differences one had to expect in a parallel universe. When reading in fiction about this topic, sometimes the "changed natural laws" comes into place, or a variation of that, where only some of the universal constants did change.
While my knowledge is a bit to small to start from one of these points, I went straight to the effect I am looking for, which would be:
When radioactive material decays in that parallel universe, it does have a fourth kind of decay
Calling it Delta Decay and call a day however did not please me. Because... all in nature comes with a price. And in physics this are usually some thermodynamic costs. That Delta Decay I am after can just not appear out of nowhere, so something else must pay for it.
But I want to keep that universe in a shape, that would it enable to bear life as we know it at planets as we know it, ideally in a copy of our Solar system. But as far as I can guess, these costs I am still ignoring would cause changes almost everywhere nuclear effects are in place. Like... solar nuclear synthesis? Warming due to radioactive decay? Making radioactivity less dangerous, or even more?
That would directly prohibit the requirements I did have on that universe. Which is... not good, I guess.
So what effects on known physics would that fourth kind of decay have?
I know, this is highly hypothetical, and if the science you use to answer this is to hard, the whole concept would most likely break apart. Lets create an environment that sets up the way this observation was made:
Imagine you are a scientist who send a proper probe through a wormhole and get readings on your screen that highly suggest your probe is being exposed to something that is made up like fourth kind of radioactive decay
Also, the "made up" exceeds the level of knowledge I do have, which is why I ended up asking such a strange question.