In a paper published by physicists at the Fermilabs Tevatron particle accelerator in Illinois, researchers claim to have found evidence for a new fundamental particle outside the traditional Standard Model of Particle Physics that may represent a fifth fundamental physical force beyond gravity, electromagnetism, strong, and weak nuclear forces.
The paper, titled Invariant Mass Distribution of Jet Pairs Produced in Association with a W boson in ppbar Collisions at sqrt(s) = 1.96 TeV (arXiv:1104.0699v1 [hep-ex]), is a reporting of findings from a research project involving the smashing together of protons and antiprotons in an attempt to create new particles. The paper shows some results that are not predicted by the existing Standard Model of Particle Physics, and which (if confirmed) would mean that theory would need to be revised or thrown out altogether.

This observation may be the results of artifacts from the creation of the long sought-after Higgs-boson particle, which is believed to be the fundamental particle that gives matter its mass. But the researchers who published these findings claim that the actual results do not conform to the predicted behavior of the Higgs. Therefore, they are proposing that it may be a different particle which had not been previously predicted!
The findings are far from conclusive though, as the "bump" in the data is only 3.2 standard deviations from the mean background noise, and so there is a roughly 0.2 to 0.3 percent chance that it may only be a random fluctuation. And when you are dealing with thousands of experimental collisions, a 0.2 to 0.3 percent chance event could happen several times. Typically, physicists look for results that lie at or beyond five standard deviations. The data could also be the result of a glitch in the sensor equipment. So this result would need to be further analyzed and probably be replicated before physicists will commit to claiming that a new particle really has been discovered.
And this announcement comes just three months after the announcement that federal budget cuts would lead to a rejection of the facility's proposed budget extension, forcing its closure this coming September.
That would mean that the only facility capable of replicating this observation would be CERN's Large Hadron Collider near Geneva, Switzerland.
This announcement also follows recent news regarding experiments at the Tevatron facility that narrowed the probably mass of the Higgs-boson, and a study published last month that proposed that top quarks were not behaving as predicted by the Standard Model in experiments.

The idea had been proposed last month that the non-conformal behavior of top quarks may suggest that a new fundamental particle (and possibly a fifth physical force) may exist. I'm not sure though, if the paper published this week is the results of the experiment regarding the top quark behavior, or if this paper is the result of a different experiment.
If the researchers at Tevatron keep this up, then that accelerator may go out with quite a bang, indeed!