International scientists said on Tuesday they had found signs of the Higgs boson, an elementary particle believed to have played a vital role in the creation of the universe after the Big Bang.
Scientists at the Cern physics research centre near Geneva said, however, they had found no conclusive proof of the existence of the particle which, according to prevailing theories of physics, gives everything in the universe its mass.
The leaders of two experiments, Atlas and CMS, revealed their findings to a packed seminar at Cern, where they have tried to find traces of the elusive boson by smashing particles together in the Large Hadron Collider at high speed.
"Both experiments have the signals pointing in essentially the same direction," said Oliver Buchmueller, senior physicist on CMS.
"It seems that both Atlas and us have found the signals are at the same mass level. That is obviously very important."
Fabiola Gianotti, the scientist in charge of the Atlas experiment, said Atlas had narrowed the search to a signal centred at around 126 GeV (Giga electron volts), which would be compatible with the expected strength of a Standard Model Higgs.
"I think it would be extremely kind of the Higgs boson to be here," she told a seminar to discuss the findings. "But it is too early" for final conclusions, she said.
"More studies and more data are needed. The next few months will be very exciting...I don't know what the conclusions will be."
The Higgs boson is, in theory, the particle that gives mass to all other fundamental particles. While its discovery would cement current knowledge about particles such as electrons and photons, results of work at Cern could also prove it does not exist.
Such an outcome would undermine the foundations of accepted theories of the make-up of the universe.
"If the first inklings of the Higgs boson are confirmed, then this is just the start of the adventure to unlock the secrets of the fundamental constituents of the Universe," said Stephen Haywood, Head of the Atlas Group at the STFC Rutherford Appleton Laboratory.
The Atlas results were followed by explanation of the second experiment, CMS.
"We are homing in on the Higgs," said Claire Shepherd-Themistocleus, head of the CMS Group at the STFC Rutherford Appleton Laboratory.
"We have had hints today of what its mass might be and the excitement of scientists is palpable. Whether this is ultimately confirmed or we finally rule out a low mass Higgs boson, we are on the verge of a major change in our understanding of the fundamental nature of matter."
Twitter feeds were choked by the volume of tweets mentioning Cern or Higgs and the webcast from Cern http://webcast.web.Cern.ch/webcast/ struggling to cope with demand from Higgs-hunters.
"It can still happen that it is a fluctuation, but all we see from both experiments is compatible with what we would expect for a Higgs signal to build up," said Buchmueller.
"But we really need the data from next year to be sure of what we're seeing."