July 4, 2012
This event was recorded with a CMS detector at a proton-proton centre of mass energy of 8 TeV.
Scientists at the European Organization for Nuclear Research, or CERN, announced July 4 that they may have found evidence of what many have dubbed the “God” particle.
Researchers with Texas Tech's High Energy Physics Group who conduct research at CERN said they and other scientists may have discovered forensic evidence – a shadow or an impression – of the elusive particle called a Higgs boson.
Nural Akchurin, a professor of physics and a member of the physics group has served in leading roles in one of the two major experiments at CERN that is called the Compact Muon Solenoid (CMS). He is an expert in calorimeters, a detector that measures the energies of fundamental particles that serve as “catcher’s mitts” to grab evidence of Higgs.
“Today (July 4), we have evidence of some kind of signal, or resonance perhaps, of some particle,” Akchurin said. “Is this signal ascribable to Higgs? This is a different question. For that, we need more data, different types of analysis. But what seems to be clear today is there is something significant that sticks out above background. Chances that this might be Higgs are not small, but it’s not necessarily Higgs either. I think we need be clear about what this means today. I don’t think we are ready to claim discovery of Higgs. I think we are prepared to say we have a signal that may be consistent with Higgs.”
The results announced July 4 are labeled preliminary. They are based on data collected in 2011 and 2012, with the 2012 data still under analysis. A more complete picture of the observations will emerge later this year after the LHC provides the experiments with more data.
The new particle is in the mass region around 125-126 GeV. Publication of the analyses shown July 4 is expected around the end of July.
Simply put, but perhaps too simply, this theoretical particle is responsible for giving mass to particles – basically nature’s smallest building blocks. It’s what makes a pencil a pencil or a rock a rock instead of loose energy floating around in space. Proof of its existence could clear up lots of questions about the universe and cement the Standard Model of Particle Physics.
Higgs is the last particle of this theory left to be discovered.
To find Higgs and answer other questions, scientists accelerate opposing beams of protons to near the speed of light in the 17-mile, circular Large Hadron Collider, which lies underground near Geneva, Switzerland. As these protons are shot around the circular tunnel, the CMS catches what is created when these protons crash into each other.
Somewhere in the melee of these particles’ high-energy collisions, researchers look for the elusive Higgs boson that can be identified by the products of its decay.
Akchurin and three other Texas Tech professors were responsible for designing and building the calorimeters that have contributed to these historic discoveries that will usher in a new age of physics. The only ones like them in existence, the calorimeters now collect data and hunt for many different phenomena as well as the Higgs boson as collisions occur.
In a decade and a half, they and more than 10 post-doctoral and doctoral students from Texas Tech have joined a phalanx of about 3,000 international scientists probing the bounds of mass and matter and answer some of the universe’s most mind-blowing riddles.
Since 2009, the international group of scientists has hoped the $8 billion Large Hadron Collider and Compact Muon Solenoid would prove the existence of matter’s smallest building blocks as well as dark matter, the secrets of black holes and how the universe began.
Barely cracking the spine of this “new physics” brand of particle science can overwhelm the average Joe. Some theories suggest there are actually 11 dimensions instead of four. Another theory says we live in a multiverse instead of a universe. Isaac Asimov or H.G. Wells contrived such ideas in fiction. Their proof may come as the experiments continue and more data is analyzed.
In the most vanilla version of the Higgs theory, Akchurin said, there must be some mechanism through which you give mass to electrons, quarks and other fundamental particles. Perhaps Higgs gives mass by holding the void of space together with strands of energy. Finding that mechanism could close the loop in assigning known masses.
“If you have Higgs, you can explain everything – or nearly most things,” he said. “This is much bigger than the atom bomb. If this project finds nothing but Higgs, that’s huge. Whatever comes out of this will be interesting.”
Sung-Won Lee, an assistant professor of Physics at Texas Tech University, watches the calorimeters and hopes to catch Higgs and other particles. As data accumulate and different analyses are put together by different groups of scientists, a clearer picture starts to emerge.
The process is arduous, and requires the work of many dedicated scientists from around the world, he said. Discovery in this experiment belongs to the many, not just a few.
About a year ago, the CMS scientists published a paper that described where Higgs wasn’t. As more data got collected, Higgs had less and less room to hide and now the data suggest that this significant excess in lighter mass region may be the Higgs boson.
There may be more than one Higgs hiding among the collision wreckage, Lee said. The theory of supersymmetry suggests there could be up to five different mass-giving particles.
For certain, he said, the particle or particles remain too elusive to catch with both hands.
Two Texas Tech professors were two of the many scientists who conducted research at CERN that produced the latest breakthrough results.
“There are too many physics processes in the context of the Standard Model that look like Higgs,” Lee said. “So, the searching for Higgs is one of the most sophisticated efforts in the LHC physics program. There are huge amounts of statistical data, understanding the other physics processes, and understanding our detector also.”
The team also searches for evidence of other new phenomena, such as dark matter. Researchers believe up to 30 percent of the universe may be made of dark matter, but as of yet, it hasn’t showed either. Still, Lee and others from Texas Tech work on the detector’s construction and maintenance to make sure it continues to record everything so researchers can come back later to understand what is going on with the data.
“Texas Tech is well integrated into this international research effort,” he said. “We play a leading role in that part. I’m happy to say we’ve done a good job over many, many years. I believe that Texas Tech’s High Energy Physics Group at CERN has excellent teamwork, and that is why we’ve done so well for many years.”
While the jury may still be out on what the signal could definitely be, Akchurin said the collider has served its purpose by not only finding this new possible particle, but also not finding anything that’s contradicted the standard model of physics. Though another accelerator may be needed to probe the bounds of the new particle, the LHC has served its purpose as a discovery machine that will still be useful to finish uncovering what already has been discovered and perhaps more.
He predicted that we may have an answer soon as to what this particle actually is.
“We could tell I think with certainly by the end of this year if Higgs is discovered or not or some other particle was discovered,” he said. “If this turns out to be a real Higgs, there must be other accelerators, or perhaps an international linear collider to be built to study this particle in detail as we always imagined it would be done. But so far, our understanding of the standard model of particle physics is correct. There has not been a single signal or evidence that suggests the Standard Model of Particle Physics is wrong or different. That’s a big deal.”
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