We don't wait until we have theoretical interpretations before publishing the discovery of a new particle. In fact, our results are kept confidential until the end of the collaboration's internal review process. In the absence of leaks, the first any theorist should hear of this new particle would have been the conference talk or press release.
This is the biggest factor
> why not, wrong matter, wrong speed?
Quantum mechanics is probabilistic. The probability of these particular particles in these particular collisions is very small. So we need to do a lot of collisions in order to have a statistically significant signal.
> but the "camera" has limitations?
Sure. While we regularly upgrade our detectors or build newer, fancier ones, there will always be some limitations.
> but measurement interpretation inefficient?
It's certainly slow. It can take months/years to infer a result from the data. The major bottleneck is people. Even the thousands-strong armies of physicists who work on the LHC experiments would take decades to fully exploit the available datasets.
I recall the Higgs had about 80-some possible decay modes. Only a handful of them could be measured above background noise. A couple of teams pursued two classes of them and found results.