The quest for the elusive Higgs boson seemed over in April, when an unexpected result from an atom smasher seemed to herald the discovery of the famous particle -- the last unproven piece of the physics puzzle and one of the great mysteries scientists face today.
Researchers were cautious, however, warning that it would take months to verify the finding.
Their caution was wise.
Scientists with the Tevatron particle accelerator at Chicago's Fermilab facility just released the results of a months-long effort by the lab's brightest minds to confirm the finding. What did they find? Nothing.
"We do not see the signal," Dmitri Denisov, staff scientist at Fermilab, told FoxNews.com. "If it existed, we would see it. But when we look at our data, we basically see nothing."
"At this point I'd say the chances are 50/50 for the Higgs to exist at all," he said.
The results -- submitted Friday to the science journal Physical Review Letters -- are a heartbreaking setback for scientists and armchair experimenters worldwide, who have been following the particle-physics treasure hunt like a baseball fan monitoring stats.
After all, the quest for the Higgs boson -- called the "God Particle" because it is believed to be the fundamental particle of matter, the smallest piece of substance that gives all other matter weight -- has been among the most prominent scientific pursuits of the last 20 years.
The Large Hadron Collider (LHC), the multi-billion dollar, 17-mile long particle accelerator in Geneva was built in part to help prove the theoretical bit's existence.
James Gilies, a spokesman for CERN, the agency that operates the LHC, told FoxNews.com that it was still too soon for his group to release any analysis -- and way too early for hopes to have been raised in the first place.
"Still too early to get excited, I'm afraid ... I think this story will reach a conclusion at the main summer conferences this year -- end of July. By then, the LHC experiments will have analyzed enough data to be able to say something," Gilies said.
Though disappointing, the results shouldn't really come as a surprise, physicists say. The strange anomaly that led to the God Particle chatter was nothing like what physicists expected from the Higgs in the first place.
"I had known from the start. It could not be a Higgs, and it can't be anything else either," Tommaso Dorigo, an experimental particle physicist who works with both atom smashers, told FoxNews.com. Denisov agreed.
"It was never the way the Higgs boson was supposed decay. It was something completely different. It wasn't even obtained by the group that was hunting for the Higgs!" he said.
So what was it, anyway? Something completely unknown and unexpected, Denisov said, which is what prompted Fermilab to drop everything and assign its top scientists to uncover an unfortunate truth: Someone forgot to carry a zero.
"Probably the way they are estimating standard model backgrounds is not correct," he said. One minor mistake and the tantalizing signal disappears, in other words. "My suspicion is that one way or the other, they're not modeling the standard background correctly."
Despite the disappointing setback, the quest for the Higgs boson is nonetheless drawing to a close.
"I'm pretty confident that towards the end of 2012 we will have an answer to the Shakespeare question for the Higgs boson, to be, or not to be?" Rolf-Dieter Heuer, director general of CERN, said at Britain's Royal Society.
Denisov agrees that the next few months could be eye-opening. And for Fermilab and the Tevatron, which is scheduled to be shut down this summer, it has to be.
"We are planning to finish our data taking later this year, and Tevatron will be shut down," he said. "It will either be seen at Tevatron in completely different decay models or at LHC or not at all."
Fermilab closing its doors probably won't end the Higgs hunt; the LHC is a more likely site for the discovery anyway, being newer, bigger, and ultimately better. And even Denisov was willing to admit that.
"It's like a Ford Model T trying to compete with a Ferrari," he joked.
Jeremy A. Kaplan is Science and Technology editor at FoxNews.com, where he heads up coverage of gadgets, the online world, space travel, nature, the environment, and more. Prior to joining Fox, he was executive editor of PC Magazine, co-host of the Fastest Geek competition, and a founding editor of GoodCleanTech.