In these experiments, researchers want to observe particles' transition from one flavor to another, and not just the common transitions, such as a down quark into an up quark, but more exotic switcheroos, such as the change of a bottom quark into a charm quark.īut to do this, scientists must increase the intensity, or number of particles produced, in their particle accelerators. Researchers' best hope of getting to the bottom of particle flavor may lie in a slew of new experiments being proposed to tackle what's called the "intensity frontier." Scientists are hoping that by studying the weird flavor behavior of particles, they might go further toward explaining matter's persistence after the Big Bang. "There have got to be some other new equations that we haven't seen the evidence for yet that also predict different kinds of matter-antimatter asymmetries." "You get a difference with these asymmetries, but it's about a billion times smaller than you need," Peskin said. Researchers have observed some asymmetries in the decay rates of matter and antimatter, but these alone are not sufficient to explain the universe as we see it. Physicists think that differences in the way matter decays compared with antimatter may explain why matter took longer to decay, and therefore survived. Most of the matter and antimatter particles created at the beginning of the universe are thought to have destroyed each other, leaving a small amount of matter left over that became the stars and galaxies we see today. When a particle and its antimatter partner meet, they annihilate each other to become pure energy. "So what happened to all the antimatter? We think this is related to flavor physics." "There's a matter-antimatter asymmetry in the universe, in the sense that the universe is made out of matter and there's no antimatter observed today, but in the Big Bang, matter and antimatter were created in equal amounts," Hewett said. Yet physicists think there should be a lot more antimatter in the universe than there is, and flavor physics may help to explain this "loss" of antimatter. Every particle is thought to have an antimatter partner, with the same mass, but the opposite charge. "They don’t exist really in everyday life."īesides searching for the origin of flavor, physicists studying these topics also hope to learn about related mysteries, such as matter's weird twin, antimatter. "They existed in the very early fractions of a second of the universe and then they decayed away," Hewett told LiveScience, referring to the rare particle flavors. Same goes for leptons: While electrons abound, some of the other flavors, such as muons and taus, are rarely found in nature. Protons and neutrons, in turn, contain just up and down quarks top and bottom, charm and strange quarks are nary to be found. The elements in the periodic table, such as carbon, oxygen and hydrogen, are composed of protons, neutrons and electrons. (Image credit: Karl Tate, LiveScience Infographic Artist)Īnd while particles do come in many flavors, our universe is preferentially made up of just a few. Second part, the status of the conservation of total lepton number isĭiscussed.Here's a breakdown of the Standard Model and the tiny particles it is responsible for. The discussionĬoncentrates mostly on rare processes involving muons and electrons. Interactions beyond the standard model of particle physics. In the first part, several aspects of charged-leptonįlavor violation are discussed, especially its sensitivity to new particles and Processes and the violation of lepton-number conservation in nuclear physics Searches for the violation of lepton-flavor conservation in charged-lepton Mechanism behind nonzero neutrino masses. Generalizations of the standard model of particle physics, and reveal the More experimental data are needed to constrain and guide possible Download a PDF of the paper titled Lepton Flavor and Number Conservation, and Physics Beyond the Standard Model, by Andre de Gouvea and Petr Vogel Download PDF Abstract: The physics responsible for neutrino masses and lepton mixing remains
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