Physicists at the Fermi National Accelerator Laboratory are planning to announce they have found a suspicious bump in their data that could be evidence of a new elementary particle or even, some say, a new force of nature.
The results,if they holdup,couldbe a spectacular last hurrah for Fermilab's Tevatron, once the world's most powerful particle accelerator and now slated to go dark forever in September or earlier, whenever Fermilab runs out of money to operate it.
"Nobody knows what this is," said Christopher Hill, a theorist at Fermilabwhowas not partof theteam. "Ifitis real, it would be the most significant discovery in physics in half a century."
One possible explanation for this mysterious bump, scientists say, is that it is evidence of a new and unexpected version of the long-sought Higgs boson. This is a hypothetical elementary particle that, according to the reigning theory known asthe StandardModel,is responsible for endowing other elementary particles with mass.
Another explanation might be that it is evidence of a new force of nature — in addition to gravity, electromagnetism, and the strong and weak nuclear forces we already know — that would manifest itself only at very short distances like thosethat ruleinsidethe atomic nucleus.
Either could shake what has passed for conventional wisdom in physics for the last few decades. Or it could be there is something they do not understand about so-called regular physics.
The Tevatron has been colliding beams of protons and their opposites, antiprotons, accelerated to energies of 1 trillion electron volts, for over two decades looking for new forces and particles. The bump showed up in an analysis of some 10,000 of those collisions collected by the Collider Detector atFermilab.
They found that in about 250 more cases than they expected, what came out of the collision were two jets of lightweight particles, like electrons, and a heavy-force-carrying particle called the W boson were produced. The team foundthatin about250times more cases than expected, the total energy of the jets clustered around a value of about 144 billion electron volts, as if they were the decay products of a hitherto unsuspected particle with that mass-energy. For comparison, a proton weighs about one billion electron volts.
This could not be Standard Model Higgs, Punzi and his colleagues concluded, as the Higgs is predicted to decay into much heavier particles, namely quarks. Moreover,the rate atwhichthese mystery particles were being produced was 300 times greater than Higgsbosonswouldbe produced.If real,itwassomething totally new,Punzisaid.