By GAUTAM NAIK
Scientists said they found a subatomic particle resembling the long-elusive Higgs boson, a landmark discovery that could explain why particles have mass and, by extension, why stars, planets and all other objects in the universe exist at all.
On Wednesday morning, hundreds of scientists assembled at the European laboratory CERN in Geneva, and many more tuned in to a live webcast to hear how fresh data from the Large Hadron Collider had conclusively revealed the existence of a Higgs-like particle.
"We have observed a new boson," said Joe Incandela of the University of California, Santa Barbara, a member of one the groups reporting the new data. His colleague Rolf-Dieter Heuer, director general of CERN, put it in simpler terms: "I think we have it," he said.
The CERN announcement follows one made on Monday by physicists at Fermi National Accelerator Laboratory, or Fermilab, near Chicago, which independently bolstered the case for the existence of the Higgs boson. However, the U.S. data didn't offer anywhere near the high level of statistical certainty required by physicists to claim a formal discovery.
The Higgs finding is expected to throw fresh light on several cosmic mysteries. For example, it could point to different predictions about how much of the universe is dark matter, an enigmatic substance that exerts a gravitational force on entire galaxies
The Higgs was proposed back in the 1960s to fill a puzzling hole in the "standard model," one of the most successful theories in physics, which describes how matter is built and how particles interact. All particles ought to have zero mass—like photons, the constituents of light—and zip around space unhindered. So why does the universe have plenty of particles with mass?
In the 1960s, a small number of theorists plugged that gap by dreaming up Higgs, which provides a theoretical explanation for how some particles could attain mass. Many other scientists poo-pooed the idea. But experimental results from the giant atom-smashing machine in Switzerland have now shown that the daring theoretical leap was, indeed, a worthy one.
Going back to Galileo and Kepler, "a 400-year-old quest to describe the world that we can see has now been completed," said Gordon Kane, professor of Physics at the University of Michigan. "It completes the standard model."
A decade ago, Dr. Kane wagered $100 that the Higgs boson would be found and cosmologist Stephen Hawking bet that it wouldn't. "I assume he's a gentleman and a scholar and will now pay up," said Dr. Kane. The University of Cambridge confirmed Dr. Hawking's bet but couldn't provide further details.
The particle is named after British physicist Peter Higgs, one of the theorists who predicted its existence nearly a half-century ago. Now 83 years old, the unassuming Mr. Higgs attended the meeting in Geneva. Bosuns themselves are named in honor of Satyendra Nath Bose, Albert Einstein's Indian collaborator.
Mr. Higgs received a round of applause as he entered the auditorium, and shed a tear when news of the Higgs-like particle was announced. "It is an incredible thing that it has happened in my lifetime," he said.
It's been a tough quest, involving thousands of scientists in dozens of countries. No one could predict the mass of the Higgs boson, so they had to hunt for it indirectly. This was done at CERN by propelling particles to near-light speed and then smashing them together to generate an array of other subatomic particles.
The researchers hoped that one such particle would be the Higgs itself, though it would almost instantly decay into different combinations of other particles. Finding it would then involve looking for statistically significant "excesses" of those particles.
The latest experiments at LHC found excesses of this sort in the data. The newly discovered particle is definitely a boson and one of the heaviest such particles to be discovered so far, CERN said. It has a mass of between 125-126 GeV, or gigaelectronvolts, making it about 134 times as heavy as a proton.
The Higgs particle offers an answer to how particles might acquire mass. Physicists hypothesize that as the universe cooled after the Big Bang, about 13.7 billion years ago, a force known as the Higgs field formed, along with the particle.
Under this scenario, the Higgs field permeates the universe, and any particles that interact with it are given a mass through the Higgs boson. The more they interact, the heavier they become. Particles that don't interact with the Higgs field are left with no mass at all.
"It is like a big vat of molasses," said Dan Green, a physicist at Fermilab. "As particles go through this, they travel at less than the speed of light and it looks like they acquire mass."
It remains to be seen whether CERN's particle is exactly the one predicted by the standard model or an exotic version. If it is a variant, that would suggest an even more intriguing description of reality.
Write to Gautam Naik at firstname.lastname@example.org
Corrections & Amplifications
The new particle found at CERN is in the mass range of 125-126 GeV, or gigaelectronvolts, making it about 134 times as heavy as a proton. An earlier version of this article incorrectly said the new particle was 125-126 times heavier than a proton.