(There is a third, heavier lepton called the tau, but it decays too fast to be observed.) But Dr. The Standard Model holds that electrons and muons are equally likely to appear in this reaction. Some rare decays of a B quark involve a daisy chain of reactions, ending in a different, lighter kind of quark and a pair of lightweight particles called leptons, either electrons or their plump cousins, muons. But these quarks are unstable and are prone to fall apart in ways that appear to violate the Standard Model. Such quarks occur in two-quark particles known as B mesons. The main character, or perhaps villain, in this drama is a particle called a B quark, one of six varieties of quark that compose heavier particles like protons and neutrons. The muon also figures in another anomaly. However, the exact position of the cracks may still be a moving target.” “Personally, I am optimistic that the cracks in the Standard Model will add up to an earthquake. El-Khadra, a physicist at the University of Illinois who helped lead a three-year effort called the Muon g-2 Theory Initiative to establish a consensus prediction. “The g-2 anomaly is still very much alive,” said Aida X. The discrepancy with theoretical predictions came in the eighth decimal place of the value of a parameter called g-2, which described how the particle responds to a magnetic field.īut two groups of theorists are still working to reconcile their predictions of what g-2 should be, while they wait for more data from the Fermilab experiment. Last year, a team of some 200 physicists associated with the Fermi National Accelerator Laboratory in Illinois reported that muons spinning in a magnetic field had wobbled significantly faster than predicted by the Standard Model. They are created by cosmic ray collisions - and in collider events - and they decay radioactively in microseconds into a fizz of electrons and the ghostly particles called neutrinos. Nobody knows where muons fit in the grand scheme of things. “Who ordered that?” the physicist Isodor Rabi said when muons were discovered in 1936. Muons are often referred to as fat electrons they have the same negative electrical charge but are 207 times as massive. Take the muon, a subatomic particle that became briefly famous last year. These results involve rare behaviors of subatomic particles whose names are unfamiliar to most of us in the cosmic bleachers. Meanwhile, a variety of experiments have revealed possible cracks in the Standard Model - and have hinted to a broader, more profound theory of the universe. “But it means there’s a bigger probability of seeing the thing you are looking for.” “That makes our lives harder in some sense because we’ve got to be able to find the things we’re interested in amongst all those different interactions,” he said. That particle is the keystone of the Standard Model, a set of equations that explains everything scientists have been able to measure about the subatomic world. The machine, the biggest and most powerful ever built, was designed to find the Higgs boson. When the CERN collider was first turned on in 2010, the universe was up for grabs. What is left to find? Almost everything, optimistic physicists say. Mitesh Patel, a particle physicist at Imperial College London who conducts an experiment at CERN, described data from his previous runs as “the most exciting set of results I’ve seen in my professional lifetime.”Ī decade ago, CERN physicists made global headlines with the discovery of the Higgs boson, a long-sought particle, which imparts mass to all the other particles in the universe. Even before its renovation, the collider had been producing hints that nature could be hiding something spectacular. In early July, the collider will begin crashing these particles together to create sparks of primordial energy.Īnd so the great game of hunting for the secret of the universe is about to be on again, amid new developments and the refreshed hopes of particle physicists. After a three-year shutdown for repairs and upgrades, the collider has resumed shooting protons - the naked guts of hydrogen atoms - around its 17-mile electromagnetic underground racetrack. In April, scientists at the European Center for Nuclear Research, or CERN, outside Geneva, once again fired up their cosmic gun, the Large Hadron Collider.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |