Sharing the same underground cavern as LHCb is a smaller instrument called MoEDAL, which stands for "Monopole and Exotics Detector at the LHC". While most CERN experiments are designed to study known particles, this one is aimed at discovering hitherto unknown ones that lie outside the present Standard Model. A monopole, for example, would be a magnetized particle consisting only of a north pole without a south one, or vice versa. Such particles have long been hypothesized, but never observed. A third experiment optimized for the forward direction is Total Elastic and diffractive cross-section Measurement (TOTEM), located near the CMS interaction point, which focuses on the physics of the high-energy protons themselves. Inside Science) -- In 2012, particle physicists detected the long-sought-after Higgs boson for the first time. This particle was the last missing puzzle piece of what physicists call the Standard Model -- the most thoroughly tested set of physical laws that govern our universe. The Higgs discovery was made possible by a giant machine in Europe, known as the Large Hadron Collider that uses a 27-kilometer ring of superconducting magnets to accelerate and then smash particles together at near the speed of light. I started on ATLAS for my PhD research. I was developing new pixel sensors to improve the measurement of particles as they pass through our detector. It's really important to make them resistant to radiation damage, which is a big concern when you put the sensors close to the particle collisions. Since then, I've had the opportunity to work on a number of different projects, such as understanding how the Higgs boson and the top quark interact with each other. Now I'm applying machine learning algorithms to our data to look for hints of dark matter. One of the biggest mysteries in physics right now is, what is 85% of the matter in our universe? We call it dark matter, but we don't actually know much about it!

For various reasons over the years, people have speculated that experiments at CERN might pose a danger to the public. Fortunately, such worries are groundless. Take for example the N in CERN, which stands for "nuclear", according to UK Research and Innovation (UKRI). This has nothing to do with the reactions that take place inside nuclear weapons, which involve swapping protons and neutrons inside nuclei. Now one must be careful. It's easy to throw numbers around a bit glibly. While there are lots of cosmic rays hitting the atmosphere with LHC energies, the situations between what happens inside the LHC and what happens with cosmic rays everywhere on Earth are a bit different. They are definitely hesitant,” said Cao. “They are hesitant because there are objections from people from all branches of physics. How can they get so much money for this project when there are so many other projects that need funding?”Cosmic ray collisions involve fast-moving protons hitting stationary ones, while LHC collisions involve two beams of fast-moving protons hitting head-on. Head-on collisions are intrinsically more violent; so to make a fair comparison, we need to consider cosmic rays that are much higher in energy, specifically about 100,000 times higher than LHC energies. A simulation of a particle collision inside the Large Hadron Collider, the world's largest particle accelerator near Geneva, Switzerland. When two protons collide inside the machine, they create an energetic explosion that gives rise to new and exotic particles. (Image credit: CERN) Strange strangelets Further, we can expand the number of cosmic targets to include neutron stars, which consist of matter so dense that whatever potentially dangerous thing we might consider will stop dead in the neutron star right after it is made. And yet the sun and the neutron stars we see in the universe all are still there. They haven't disappeared. Safety assured!

Right now, we've got five years of justification of the study to do, then probably another five years or so of detailed engineering design. Then we would proceed at whatever pace we could, which was limited by the money,” said Newbold. “It’ll probably be a minimum of 20 years from now and maybe longer.”

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Those are but two ideas for how a supercollider could pose a threat, and there are more. We could list all of the possible dangers, but there remains something more unsettling to keep in mind: Since we don't know what happens to matter when we start studying it at energies only possible with the LHC (that is, of course, the point of building the accelerator), maybe something will happen that was never predicted. And, given our ignorance, maybe that unexpected phenomenon might be dangerous. The paths of the particles inside the detector are controlled by a gigantic electromagnet called a solenoid. Despite weighing 12,500 metric tons, it's quite compact, as the detector's name suggests. That middle word, muon, refers to an elusive particle similar to the electron but much more massive, which requires its array of subdetectors wrapped around the solenoid. We are in a situation where the Standard Model cannot explain various phenomena,” said Gianotti. “There are many other theories, but we have no clue which one is the right one. And so, making a step forward in terms of energy scale … can help redirect our thoughts.” The bad Two of the four collision points around the circumference of the LHC are occupied by large general-purpose detectors. These include the Compact Muon Solenoid (CMS), which can be thought of as a giant 3D camera, snapping images of particles up to 40 million times per second.

According to the physics magazine CERN Courier, the LHC has also found around 60 previously unknown hadrons, which are complex particles made up of various combinations of quarks. Even so, all those new particles still lie within the bounds of the Standard Model, which the LHC has struggled to move beyond, much to the disappointment of the numerous scientists who have spent their careers working on alternative theories. LHC Safety Assessment Group " Review of the Safety of LHC Collisions Addendum on strangelets". June 2008. The climate experiment is called CLOUD, which gives a strong hint of what it's about, although the name stands for Cosmics Leaving Outdoor Droplets. Earth is under constant bombardment by cosmic rays, and it's been theorized that these play a role in cloud formation by seeding tiny water droplets. It isn't an easy process to study in the real atmosphere with real cosmic rays, so CERN is creating its own cosmic rays with the accelerator. These are then fired into an artificial atmosphere, where their effects can be studied much more closely. Making antimatter

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To give a sense of scale, the LHC collides particles together with a total energy of 13 trillion (or tera) electron volts of energy (TeV). The highest-energy cosmic ray ever recorded was an unfathomable 300,000,000 TeV of energy. The energy required to create particles like the Higgs boson is measured in what are called gigaelectronvolts, or GeV. The LHC can generate collisions with an energy of 13,000 GeV -- more than a hundred times the 125 GeV mass-energy equivalence of the Higgs boson. It can produce only one Higgs boson for every 10 billion collisions, due to all the energy expended on all the lighter particles.

The LHC's biggest moment came in 2012 with the discovery of the Higgs boson. Although widely referred to as the "God particle", it's not really as awesome in itself as that name might suggest. Its huge significance came from the fact that it was the last prediction of the Standard Model that hadn't yet been proven. But the Higgs boson is far from being the LHC's only discovery. What immediately follows are the weaker (but still compelling) reasons why this possibility is, well, not possible, and in the next section you will see the cast-iron and gold-plated reasons to dismiss this and all other possible Earth-ending scenarios. In 2012, the Institute of High Energy Physics of the Chinese Academy of Sciences announced a plan to build the next great supercollider. The planned Circular Electron Positron Collider will be 100 kilometers around, almost four times larger than the Large Hadron Collider, or LHC. Then in 2013, the LHC's operator, known as CERN, also announced their plan for a new collider, named simply the Future Circular Collider. Cosmic rays of that energy are rarer than the lower energy ones, but still 500,000,000 of them hit the Earth's atmosphere every year. For reference, a single teraelectronvolt is equivalent to 1 trillion electron volts (an electron volt, a unit of energy, is equivalent to the work done on an electron accelerating through the potential of one volt.)The LHC forward (LHCf) detector, located close to the ATLAS interaction point, uses particles thrown forward in collisions as a means of simulating cosmic rays under laboratory conditions. Further, along the beam trajectory is the Forward Search Experiment (FASER), designed to look for light, weakly interacting particles that are likely to elude the larger detectors. While physicists know they cannot know the results without building the instruments and doing the experiment, the economics of such exploration is more open to debate. What kind of price are we willing to pay for a better understanding of our universe? Many of the LHC's most important experiments, including the discovery of the Higgs boson, utilize the general-purpose detectors ATLAS and CMS. But it also has several other more specialized detectors that can be used in specific types of experiments. Skeptics have proposed that the LHC would produce many possible dangers, ranging from the vague fear of the unknown to some that are strangely specific. One of the key mysteries of the universe is the striking asymmetry between matter and antimatter — why it contains so much more of the former than the latter. According to the Big Bang theory, the universe must have started with equal amounts of both. Yet very early on, probably within the first second, virtually all the antimatter had disappeared, and only the normal matter we see today was left. This asymmetry has been given the technical name 'CP violation', and studying it is one of the main aims of the Large Hadron Collider's LHCb experiment.