This new energy frontier will allow researchers to probe beyond the current boundaries of our understanding of the fundamental structure of matter in search of new discoveries.
In order to make the most of the new accelerator conditions, the discovery experiments, ATLAS and CMS, have undergone further upgrades during the shutdown period. This sits very close to the point where the protons slam into each other, creating a cascade of other subatomic particles. Because the IBL sits closer to the action than the original detectors — which are also still in use — it provides an additional measurement point for particles originating from the collisions, allowing greater accuracy on the resulting measurements.
The IBL will be especially important for identifying heavy particles, such as bottom quarks , which are produced during decays of short-lived particles such as the Higgs boson and are crucial for measurements of the top quark which decays to a bottom quark and W boson. Having measured the mass of the Higgs boson by looking at the way it decays into other particles, LHC scientists then went one step further. In they measured the properties of the boson, all of which proved consistent with the predictions of the Standard Model.
Now physicists want to know if the Higgs they found is hiding any surprises. Rolf Heuer, the director-general of Cern, which operates the LHC, told engineers and scientists at the lab: "Congratulations.
Thank you very much everyone… now the hard work starts". The beams have arrived a week or so later than originally scheduled, due to a now-resolved electrical fault. The protons are injected at a relatively low energy to begin with.
But over the coming months, engineers hope to gradually increase the beams' energy to 13 trillion electronvolts: double what it was during the LHC's first operating run. After GMT, engineers began threading the proton beam through each section of the enormous circle, one-by-one, before completing multiple full turns. It was later joined by the second beam, in parallel. The experiment teams have already detected "splashes" of particles, which occur when stray protons hit one of the shutters used to keep the beam on-track.
If this happens in part of the pipe near one of the experiments, the detectors can pick up some of the debris. Big unknowns. Physicists are frustrated by the existing Standard Model of particle physics. It describes 17 subatomic particles, including 12 building blocks of matter and 5 "force carriers" - the last of which, the Higgs boson, was finally detected by the LHC in Prof Tara Shears, from the University of Liverpool, works on one of the LHC's four big experiments that will soon recommence their work, slamming protons together and quantifying the fallout.
In order to explain several baffling properties of the universe, things beyond the Standard Model have been proposed - but never directly detected. For LHC protons to reach their collision energy of 14 TeV, the high technology superconducting electromagnets have to sustain a field of 8. To achieve this, the cable windings must be cooled to a temperature of 1. In the tests, the magnet, in its cryostat filled with superfluid helium, reached the LHC design field of 8.
The first "quench" occurred at 8. The magnet was then powered again to 8. This confirmed the validity of the magnet design and the ability of industry to take up the challenge of constructing the LHC. To study the collisions of the tiny quarks locked deep inside protons requires a microscope on a larger scale than ever before built. But the microscope alone - LHC's kilometre ring of superconducting magnets - is not enough. Researchers using it have to have sharp eyesight.
Their 'eyes' are two mighty detectors, called ATLAS and CMS, each as high as a five-storey building, built like a Russian doll, with one module fitting snugly inside the other around the beam collision point at the centre. Such a centre would help China to become more internationalized, more open towards the world.
And it is going to bring more resources to the scientific community. People at the very beginning may feel that it is not as convenient compared to Switzerland.
But we hope that the collider would be a good thing, at least for the Chinese. Historically, we always have had many particle-physics centres, although now we have fewer and fewer. The spallation neutron source in Dongguan is now operating. It is small but good enough.
IHEP is also planning a 1. This is a circular electron accelerator that can generate synchrotron radiation — X-rays with extremely high intensity. These are useful for almost every research discipline, including materials science, chemistry, biology, environmental science, geology and medicine.
We believe the government is going to give its final approval for the project by the beginning of next year, and then we can start construction. We think it would be a world-leading machine. Most light sources are upgrades from existing machines, so they are limited.
We can use the best configurations, the best technologies, without constraints.
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