As The Large Hadron Collider Rises So Do The Hopes Of Physicists.

And so the great game of hunting for the secret of the universe is about to begin again, in the midst of new developments and the renewed hopes of particle physicists. Even before its renovation, the accelerator hinted that nature could hide something spectacular. Mitesh Patel, a particle physicist at Imperial College London conducting an experiment at CERN, described the data from his previous series as “the most exciting set of results I have ever seen in my professional life”. A decade ago, CERN physicists made world headlines with the discovery of the Higgs boson, a highly sought-after particle that adds mass to all other particles in the universe. What remains to be found? Almost everything, say optimistic physicists. When the CERN accelerator was first activated in 2010, the universe was ready. The machine, the largest and most powerful ever built, was designed to find the Higgs boson. This particle is the cornerstone of the Standard Model, a set of equations that explains everything scientists have been able to measure about the subatomic world. But there are deeper questions about the universe that the Standard Model does not explain: Where did the universe come from? Why does it consist of matter and not antimatter? What is the “dark matter” that floods the world? How does the Higgs particle itself have mass? Physicists hoped some answers would come in 2010 when the big accelerator was first put into operation. Nothing appeared except Higgs – in particular, no new particle that could explain the nature of dark matter. Disappointingly, the Standard Model remained steadfast. The accelerator was completed in late 2018 for extensive upgrades and repairs. According to the current schedule, the accelerator will run until 2025 and then shut down for another two years to install other extended upgrades. This set of upgrades includes improvements to the giant detectors at the four points where the proton beams collide and analyze the wreckage of the collision. From July, these detectors will have their job. Proton beams have been compressed to become more intense, increasing the chances of protons colliding at transit points – but confusing detectors and computers in the form of multiple particle sprays that must be distinguished from each other. “The data will come at a much faster rate than we were used to,” he said. Patel. Where once only a few collisions occurred at each beam junction, now it would be more than five. “It makes our lives more difficult in a way because we have to be able to find the things that interest us in the midst of all these different interactions,” he said. “But it means you are more likely to see what you are looking for.” Meanwhile, a variety of experiments have revealed possible cracks in the Standard Model – and hint at a broader, deeper theory of the universe. These results include rare behaviors of subatomic particles whose names are unknown to most of us in cosmic bleach. Take the muon, a subatomic particle that became famous for a while last year. Muons are often referred to as fat electrons. have the same negative electric charge but have 207 times greater mass. “Who ordered it?” said physicist Isador Rabi when muons were discovered in 1936. No one knows where the muons fit into the big picture. They are created by collisions of cosmic rays – and accelerator events – and decay radioactively in microseconds into a wave of electrons and imaginary particles called neutrinos. Last year, a team of about 200 physicists associated with the Fermi National Accelerator Laboratory in Illinois reported that muons spinning in a magnetic field oscillated significantly faster than predicted by the Standard Model. The discrepancy with the theoretical predictions appeared in the eighth decimal place of the value of a parameter called g-2, which described how the particle responds to a magnetic field. The scientists attributed the fractional but real difference to the quantum whisper of the still unknown particles that would be implemented for a while around the muon and would affect its properties. Confirmation of the existence of particles would finally break the Standard Model. But two groups of theorists are still working to reconcile their predictions of what the g-2 should be, while waiting for more data from the Fermilab experiment. “The g-2 anomaly is still very much alive,” said Aida X. El-Khadra, a physicist at the University of Illinois at Urbana-Champaign, who helped lead a three-year effort called the Muon g-2 Theory Initiative to create a consensus forecast. “Personally, I am optimistic that the cracks in the Standard Model will accumulate in an earthquake. However, the exact location of the cracks can still be a moving target. “ The muon also appears in another anomaly. The main character, or perhaps the bad guy, in this drama is a particle called quark B, one of six quark varieties that make up heavier particles such as protons and neutrons. B means down or, perhaps, beauty. Such quarks occur in particles of two quarks known as mesons B. But these quarks are unstable and are prone to collapse in ways that seem to violate the Standard Model. Some rare splits of a quark B include a chain reaction that results in a different, lighter type of quark and a pair of light particles called leptons, or electrons, or their plump cousins, muons. The Standard Model argues that electrons and muons are equally likely to occur in this reaction. (There is a third, heavier lepton called tau, but it breaks down very quickly to notice.) But Dr. Patel and his colleagues found more electron pairs than muon pairs, violating a principle called the universality of leptons. “He could be a typical model killer,” said Dr. Patel, whose team explored Q quarks with one of the Large Hadron Collider detectors, the LHCb. This anomaly, like the magnetic anomaly of the muon, indicates an unknown “influencer” – a particle or force that interferes with the reaction. One of the most dramatic possibilities, if these data are valid in the upcoming series of accelerators, says Dr. Patel, is a subatomic conjecture called leptoquark. If the particle exists, it could bridge the gap between two classes of particles that make up the material universe: light leptons – electrons, muons and also neutrinos – and heavier particles such as protons and neutrons, which are made up of quarks. Temptingly, there are six types of quarks and six types of leptons. “We are moving in this direction with more optimism that there could be a revolution,” he said. Patel. “Fingers crossed”. There is another particle in this zoo that behaves strangely: the W boson, which carries the so-called weak force responsible for radioactive decay. In May, physicists at the Collider Detector at Fermilab, or CDF, reported a 10-year effort to measure the mass of this particle, based on about 4 million W bosons collected from collisions at Fermilab’s Tevatron, the world’s most powerful accelerator. . until the Large Hadron Collider was built. According to the Standard Model and previous mass measurements, the W boson should weigh about 80.357 billion electron volts, the mass-energy unit preferred by physicists. By comparison, the Higgs boson weighs 125 billion electron volts, about as much as an iodine atom. But W’s CDF measurement, the most accurate ever, was higher than projected at 80.433 billion. The experimenters estimated that there was only one chance in 2 trillion – 7-sigma, in physics terminology – that this discrepancy was a statistical misfortune. The mass of boson W is related to the masses of other particles, including the famous Higgs. Therefore, this new discrepancy, if maintained, could be another crack in the Standard Model. However, all three anomalies and theories’ hopes for a revolution could disappear with more data. But for the optimists, all three point in the same encouraging direction to hidden particles or forces that interfere with “known” physics. “So a new particle that could explain both g-2 and mass W could be accessible to the LHC,” said Kyle Cranmer, a physicist at the University of Wisconsin who is working on other experiments at CERN. John Ellis, a theorist at CERN and Kings College London, noted that at least 70 papers have been published that offer explanations for the new W-mass deviation. “Many of these explanations also require new particles that may be accessible to the LHC,” he said. “Did I mention dark matter? Well, a lot of things to look out for! “ For the upcoming match, Dr. Patel said: “It will be exciting. It will be hard work, but we are really willing to see what we have and if there is anything really exciting in the data. ” He added: “You could make a scientific career and not be able to say that once. So I feel like a privilege. “