If physics of elementary particles get their way, new accelerators will be able one day to thoroughly explore the curious sub-atomic particle in physics — the Higgs boson. Six years after the discovery of this particle at the Large hadron Collider, physicists are planning a huge new machine that will last for tens of kilometers in Europe, Japan or China.
New colliders: what are they
The discovery of this subatomic particle, which reveals the origin of mass, led to the completion of the Standard model — a comprehensive theory of particle physics. And also was a landmark achievement for the LHC, currently the largest accelerator in the world — after all, the search for the Higgs boson, though not only, it was built.
Now physicists want to go deep into the mysteries of the Higgs boson in the hope that it will be the key to resolving the protracted problems of physics of particles. “The Higgs particle is special,” says physicist Ipang van, Director of the Institute of high energy physics in Beijing. “We believe that the Higgs is a window to the future”.
The large hadron Collider, aka LHC, consisting of a ring in length of 27 kilometers, inside of which the protons are accelerated to nearly the speed of light and collide billions of times per second, almost reached the limit of their capabilities. He coped well with the discovery of the Higgs, but not suitable for detailed study.
So particle physics demand a new kind of particle Collider designed to run heaps of Higgs bosons. It was proposed several projects for these new powerful machines, and scientists hope that these factories the Higgs could help to find solutions to glaring weaknesses of the Standard model.
“The standard model is not a complete theory of the universe,” says experimental physicist particle Galina Abramovich of tel Aviv University. For example, this theory does not explain dark matter, an unidentified substance, the mass of which is necessary to account for space observations, such as movement of stars in galaxies. It also doesn’t explain why the universe is made of matter, while antimatter is very rare.
Supporters of the new colliders argue that a careful study of the Higgs boson may point scientists towards solving these mysteries. But among scientists striving for new costly accelerators are not supported. Besides, it is unclear that it could find these machines.
Next in line
First in line is the international linear Collider in the North of Japan. Unlike the LHC, where particles move on a ring of MLK accelerates two beams of particles in a straight line directly at each other, in all of its 20-mile length. And instead of trying to push the protons together, it pushes electrons and their antimatter partners, positrons.
However, in December 2018, an interdisciplinary Committee of the Science Council of Japan opposed the project, calling on the government to exercise caution with its support and asking the question, justify the expected scientific achievements the cost of the Collider, which is currently estimated at $ 5 billion.
Supporters argue that the plan MLK collisions of electrons and positrons, and not protons, has a number of major advantages. Electrons and positrons are elementary particles, i.e. they have smaller components, and protons consist of smaller particles — quarks. This means that the collision of protons will be more chaotic and create more useless garbage particles, which will have to sift through.
Furthermore, in collisions of protons only part of the energy of each proton actually gets into a collision, whereas in electron-positron colliders the particles are transferred into the clash full of energy. This means that scientists can set the collision energy to maximize the number of produced Higgs bosons. At the same time, MLK will require only 250 billion electron volts for the production of Higgs bosons compared to 13 trillion electron volts in the TANK.
From MLK, “the quality data will be much higher,” says the physicist of elementary particles Lyn Evans of CERN, Geneva. One out of every 100 collisions on MLK will produce the Higgs boson, while at the LHC this happens every 10 billion collisions.
It is expected that the Japanese government will take a decision on the Collider in March. Evans says that if MLK is approved, it will take about 12 years. Later, the accelerator can also be upgraded to increase energy, which it can achieve.
At CERN there are plans to create a similar machine — the Compact linear Collider (CLIC). It will also push electrons and positrons, but at higher energies than MLK. His energy will start from 380 billion electron volts and will increase to 3 trillion electron volts in a series of updates. To achieve these higher energies, it is necessary to develop a new technology for accelerating particles, and then CLIC appear clearly not before MLK, says Evans, who heads the cooperation of researchers of both projects.
Running in a circle
Two other planned Collider in China and Europe, will be round like the TANK, but a lot more: each with a circumference of 100 kilometers. This is a rather large circle to double circle the country of Liechtenstein. It is almost the length of the ring road.
The circular electron positron Collider, the construction of which in China is not yet defined, will push the electrons and positrons 240 billion electron volts, according to the conceptual plan that was formally presented in November and protected by the van and the Institute of high energy physics. This accelerator can be later updated for colliding protons at high energies. Scientists say that could begin construction this machine cost 5-6 billion dollars by 2022 and finish by 2030.
And at CERN the proposed Future circular Collider, the BPC will also start operation in stages, by colliding electrons with positrons, protons and later. The ultimate goal will be to reach proton collisions at 100 trillion electron volts, which is more than seven times the energy TANK.
Meanwhile, scientists shut down LHC for two years, upgrading the machine to work at higher energy. In 2026 earn a TANK with high luminosity, which will increase the frequency of collisions of protons at least five times.
A Portrait Of Higgs
When the TANK was built, scientists were fairly confident that you will find with it the Higgs boson. But with new machines it is unclear what new particles to look for. They are simply to catalogue how strongly the Higgs interacts with other known particles.
Measurement of the interactions of the Higgs can confirm the expectations of the Standard model. But if observation differ from expectations, the discrepancy may indirectly indicate the presence of something new, such as the particles constituting dark matter.
Some scientists hope there will be something unexpected. Because the Higgs boson mystery: congenerous these particles in liquid, similar to molasses. Why? We have no idea, says physicist particles Michael Peskin from Stanford University. This fluid permeates the Universe and slowing down of the particles and giving them weight.
Another mystery is that the mass of the Higgs in a million billion less than expected. This oddity suggests that there are other particles. Previously, scientists thought that can answer the problems of the Higgs by using the theory of supersymmetry — a consonant where each particle has a heavier partner. But this did not happen, because the TANK found no trace of supersymmetric particles.
Future colliders may still find evidence of supersymmetry or otherwise hint at new particles, but the scientists will not give promises. Now they are more engaged in the development of priorities and bringing arguments in favor of the new colliders and other experiments in particle physics. One thing is certain: the proposed accelerator will explore unknown territory with unpredictable results.