Geneva, Switzerland – The European Organization for Nuclear Research reported on Tuesday they might have found a new fundamental particle of nature, a discovery made by scientists working on the Large Hadron Collider (LHC) –the biggest particle accelerator in the world.
Physicists reported new data this week covering a year of observations from two different detectors inside the LHC: ATLAS and CMS. They have proposed different ideas about what might have been found with the new experimental results.
Scientists say it is too soon to say something new has been discovered, but if they did discover something they just don’t know what it is yet. Theories in the new research papers range from positing new flavors of the Higgs boson, particle thought to explain how other particles get their mass, to proposing candidates for dark matter. There are other theories that say that maybe it’s a particle related to gravity.
But if they did discover a new particle or particles, or if dark matter is confirmed, it would mean the reigning model of particle physics, the Standard Model, needs to be extended and possibly replaced.
How does the LHC work?
The LHC smashes protons together at near light speed, with energies of 13 trillion electron volts, higher than any particle accelerator has ever achieved. The collaboration of over 3000 physicists, technicians, and engineers from over 40 countries was necessary to keep the detector collecting the data at optimal levels.
When the protons crash into each other their energy gets converted to mass so theoretically, the 13 GeV should get converted to mass in the form of a new particle or particles. If the same old particles are being created, physicists know what to expect from these collisions; it’s when they see a spike or anomaly in the energies of the particles that they start looking for something new.
In this case, the detectors picked up a kind of double flash of gamma-ray photons (called a di-photon) center at an energy level of 750 GeV, which could indicate the presence of a new kind of particle but to determine a new particle have been discovered physicists like to have what they call “5-sigma” certainty, which is a measure of how likely it is that what you’re seeing is by chance. In this opportunity the result was 3.9 sigma, an intriguing measure bot not enough to declare a new particle have been found.
“When we saw this tiny hill in the diphoton mass spectrum in ATLAS we’re like, ‘Hmmmmm…‘ and then we instantly started poking it with our most ruthless experimental sticks, as usual, to see if it would withstand scrutiny. After poking and prodding (e.g., ruling out detector problems, multiple-checking the statistical methods) it was still there. But, again, the ‘it’ is just a slight uptick that, statistically, is just a hint. We will have to remain on the edges of our seats for a few more months to years.” particle physicist James Beacham, a post-doctoral research fellow with the Ohio State University, said in an interview with Discovery News.
The accelerator is now shut down for the normal end of the year technical stop. Now it will be cleaned out contaminant from the cold-box for the CMS magnet. The accelerator will then turn on again sometime in March next year to start colliding protons again so more data sample can be collected and many physicists seem confident that future data will show that there is something there.
What’s coming next?
Kyle Cranmer, a physicist on one of the teams at CERN said they have a lot of mysteries that must be addressed. He said during an interview with Here & Now‘s Jeremy Hobson that the need to confirm the theories proposed.
“When we do these experiments, we’re looking for some hint, some deeper picture as to what the rules of the game are for the universe and what everything’s made out of, and this would be the first big hint in that direction,” Cranmer said in the interview.
Scientists hope they will have significantly more data by next summer that could either reinforce this particular bump or flatten it out.
Source: Discovery News