The coming year is shaping up to be an important one for physicists all around the world. Earlier this month, it was announced that two teams of experimenters have narrowed down the field for locating the Higgs boson using the Large Hadron Collider (LHC).
“Scientists say that two experiments at the LHC see hints of the Higgs at the same mass, fuelling huge excitement. But the LHC does not yet have enough data to claim a discovery. Finding the Higgs would be one of the biggest scientific advances of the last 60 years. It is crucial for allowing us to make sense of the Universe, but has never been observed by experiments.” (link) Prof Rolf-Dieter Heuer, director-general of Cern, the organization that runs the LHC told BBC News: “We can be misled by small numbers, so we need more statistics,” but added: “It is exciting.”
Columbia University physics professor and author Brian Greene was visiting ASU for a conference on quantum mechanics when the announcement was made. He and ASU’s own theoretical physicist and best-selling author Lawrence Krauss made a video to answer questions about the Higgs and the LHC.
Krauss says the existence of the Higgs would be amazing but he also mentions that sometimes as a scientist it’s even more exciting to be wrong. Greene agreed saying “We love the unexpected…but it’s great to see something that I’ve learned as a student, graduate student, talked to students, actually apparently coming to life.”
Krauss said, “It’s an amazing testimony to the power in some sense the human intellect.”
The best part about this announcement is that it really demonstrates what good science is all about. The Standard Model for physics has been predicting the Higgs boson (and other particles) for nearly 50 years. But actually testing the two hypotheses, the first hypothesis that it is does exist and the null hypothesis that it doesn’t exist, has been complicated. Even with this announcement scientists are not saying all their hard work is done. They have acknowledged that the statistical data isn’t definitive enough to say for certain that the Higgs exists.
University of Illinois (UI) physicist Tony Liss, who is part of the ATLAS detector project, one of two teams of scientists looking for the Higgs boson told the The News-Gazette (link) this:
“The Standard Model is a collection of several theories describing ‘everything we’ve observed for the last 50 years, basically,’ Liss said.
It predicted the existence of certain forces before they were found, such as quarks, and ‘so far it’s been pretty accurate,’ Liss said. ‘We need this one last piece.’
Scientists announced in early December they had defined a range of likely masses for the Higgs boson but had not found conclusive proof of its existence.
That’s because they need more definitive statistical results, Liss said. Physicists search for the particles on ‘a big background of noise’ that can mimic the signal from the particles themselves, Liss said.”
But they have it seems narrowed down the field of frequency to locate the Higgs boson. Mark Neubauer, a fellow with UI’s National Center for Supercomputing Applications and another Atlas group member said: “What intrigued him was that both the Atlas group and the other team of scientists, the CMS group, found a hint of a signal at the same mass, 125 Gev, or billion electrovolts, and not anywhere else.
The mass of the Higgs boson is not known, so scientists have to search all masses within the range predicted by the Standard Model, anywhere from 100 to 1,000 GeV, he said. Subsequent experiments suggested the Higgs boson should be at the low end, between 100 and 130 GeV, so the recent findings fit, he said.
‘If I had seen either of the experiments alone, it’s not that convincing,’ Neubauer said. ‘I think put together, the fact that the hint exists at almost the same Higgs boson mass is a fact that I find hard to be a coincidence.’
Scientists will spend much of 2012 repeating the experiments to verify the Higgs boson’s existence — or prove that it doesn’t exist.
‘What we really need is more data, more collisions,’ Neubauer said. ‘The data we’re going to be collecting over 2012 will be definitive.’