Article: How Long Do Neutrons Live? Physicists Close In on Decades-Old Puzzle
Author: Alexandra Witze How long a neutron lives has been a question that the scientists couldn’t seem to agree on an answer to. Finding the neutron lifetime is important, as it would contribute to finding out how much of the other elements such as helium and hydrogen were formed at the beginning of the creation of the universe. So far the scientists have tried two different methods to measure the lifetime of a neutron. One method they used was the “bottle” method, where they put some particles in a bottle and count how many of them remain after a certain period of time. As a result, they got 14 minutes 39 seconds. However, when they used another method called the “beam” method where they put in neutrons into a detector that counts the protons generated as the neutrons decay, the result turned out to be 8 seconds longer than that of the bottle method. One of the possible reasons for this difference is that one of the two methods is wrong, and another possibility is that it is due to some unseen factor. It’s possible that the neutrons decay not only into protons but also into dark matter, which is what makes up much of the universe’s matter. To test these possibilities, a group of physicists are trying to combine the two methods by putting a particle detector inside a bottle and counting neutrons using both methods. Besides this, the beam experiments are constantly being done to measure the neutron lifetime in a short period of time - less than a second. I believe that finding out the neutron’s lifetime is important as it could lead to the measurements(lifetime) of other subatomic particles as well. I think it’ll also be really interesting if the neutrons actually turn out to decay into dark matter, because then it will lead to discoveries about that unseen material. I wonder what the result of the mixing of the two methods might be, it could either be the same as the result from one of the two methods, or it could be some time between the two results, like 14 minutes 43 seconds. https://www.scientificamerican.com/article/how-long-do-neutrons-live-physicists-close-in-on-decades-old-puzzle/
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Article: Physicists Solve a 35-Year-Old Mystery Hidden inside Atomic Cores
Author: Rafi Letzter The EMC effect is an observation that the nucleons act differently when they’re inside an atom versus when they are free. The speed of quarks, the subatomic particles that compose the protons and neutrons, decrease inside an atom. Scientists were not able to explain what causes this effect, because the interactions inside quarks are way stronger than that of the nucleus, meaning the interactions inside quarks wouldn’t be easily influenced by an external force. Quarks are bound together by about 1000 MeV while the protons and neutrons in a nucleus are bound together by about 8 MeV. When this group of scientists did some experiments and looked at the nucleons’ interactions, they found out that in most cases protons and neutrons don’t overlap with each other but in some cases they do, becoming “correlated pairs.” When they do overlap, a large amount of energy flows in between them, causing changes in their bound behavior and structure - this is caused by the strong force. The data suggest that this happens in only a few nucleon pairs. However, the change in their behavior is so big that the average results become skewed. So the EMC effect isn’t something that results from the majority of the nucleons, but it rather is a result of just a few odd cases. I believe that more experiments should be done on this topic and more kinds of different nuclei should be observed because they said that the effect was observed in about 20% of the nucleons that they have looked at. Meaning, there could be more types of nuclei with correlated pairs out there that haven’t been investigated, which might then lead to a conclusion that the EMC effect isn’t just a result of a minority of anomalies, but is observed more commonly. Although the author explains the experiment and the findings, he himself seems to be uncertain about the conclusion as he says that the “particle physicists seem to have solved this problem with too many no-good solutions.” https://www.scientificamerican.com/article/physicists-solve-a-35-year-old-mystery-hidden-inside-atomic-cores/ Article: Physicists Lay Out Plans for a New Supercollider
Author: Davide Castelvecchi CERN(European Council for Nuclear Research), declared that they’re planning on building a new accelerator that’s much longer and more powerful than the Large Hadron Collider(LHC), which is the world’s largest collider at this moment. This new Future Circular Collider(FCC) might help researchers find new particles or find answers to nature's mysteries by examining the highest energies possible. CERN has proposed two different designs for the machine. One of them would break electrons and their antimatter counterparts, positrons, allowing the scientists to study known particles like Higgs boson with higher precision than LHC. Another option would be a hadron collider (proton-proton) that could reach much higher energies than LHC, up to 100,000 GeV. Both types of colliders would contribute to looking for completely new particles that are not observed with current technology, or clarify the current unexplainable scientific phenomena. The author thinks that building of only one would be sufficient, as they both would result in a similar conclusion. Although some physicists say that there might not be new physics in the energy regime that a collider like this would reach, I believe it’s necessary to build FCC so that more particles could be discovered and the scientific phenomena around us could be explained. And even though the author mentioned the opposing viewpoint on the issue, it seems that he’s in favor of building FCC, as he lays out the its advantages throughout the article. However, they should think more about consequences the building of the collider might cause. Scientists suggested that the operation of LHC might cause a formation of a black hole somewhere in the universe, creation of a strange matter and magnetic monopoles, etc., and since this new collider would push up to higher energy, its consequences might be more extreme. www.scientificamerican.com/article/physicists-lay-out-plans-for-a-new-supercollider/ Article: Measurement Shows the Electron’s Stubborn Roundness
Author: Mindy Weisberger The Standard Model, a long-standing physics theory that describes how particles and forces behave, suggests that the particles around electrons affect their shape, but in a very small scale that it cannot be detected with the technology we have now. However, other theories such as the Supersymmetric Standard Model suggests that every particle has a heavyweight antimatter partner which could deform electrons to a certain extent that scientist could observe. The method of testing this new suggestion was zapping the molecules with laser and looking at the light reflected by them; the bends in the light would represent an electric dipole moment, which is a moment where the electron’s spherical shape looks deformed(not perfectly round). However, no bends were observed during the experiment. This could mean that the particles do not exist or that they do exist but might be different from what the scientists expected them to be. This experiment could related to the search for dark matter as well. Dark matter can’t be observed directly like these subatomic particles, but scientists know that it exists due to its impact on other planets. I didn’t think that people would question the roundness of an electron. But the alternative theories seem to have reasons as well. The particles surrounding electrons could have a bit more influence than they seem to have at the moment, thus making the electron’s shape look deformed. I believe that the particles or the bends in the reflected light might be observed if the technology could be more developed so that the electrons could be observed at a higher resolution. But if the resolution isn’t the problem, then the scientists should probably look for other methods to observe the particle behavior around the electrons that supports the existence of the hypothetical antimatter partner particles. And if they succeed in doing this, it could open up the possibilities of the observation of the dark matter as well. https://www.scientificamerican.com/article/measurement-shows-the-electrons-stubborn-roundness/ Article: Physicists Observe the Higgs Boson’s Elusive Decay
Author: Chelsea Gohd Higgs boson, an elementary particle in the Standard Model of particle physics produced by the Higgs field’s quantum excitation, was first found in 2012. When its existence was first predicted, a theory that a Higgs boson particle will decay into fundamental particles called bottom quarks(b quarks) was presented as well. And in August 28, 2018, CERN (European Organization for Nuclear Research) announced that they have observed the Higgs boson decay into b quarks. This is the first direct piece of evidence that supports the theory that the Higgs boson gives masses to quarks, meaning it supports the Standard Model, and therefore it would contribute to helping us understand the world and the universe. For now it seems like all the pieces of evidence are supporting the Standard Model, but there’s a possibility that the scientists would find a different evidence that opposes the Standard Model, and if so, the way we understand the way the universe functions could change completely. The only thing I knew about Higgs boson was that it explains how objects have mass. I didn’t know that its particle would decay into b quarks. Based on what I’ve read, I think that this observation is a huge step for us in understanding how the universe functions. The author mostly laid out how important this discovery is and how it could practically explain why the objects have mass or how they’re given masses, and I do agree with her opinion on its importance, but I also believe that we cannot ignore the fact that a whole new piece of evidence/theory might come up. However, there’s also a possibility that both the Standard Model and the new theory might be right and thus integrate into a more accurate and developed conclusion, so the scientists should keep on trying to discover more on this topic. https://www.scientificamerican.com/article/physicists-observe-the-higgs-bosons-elusive-decay/ Article: Thousands of Exotic "Topological" Materials Discovered through Sweeping Search Author: Elizabeth Gibney
In the past, only a few hundred of topological materials were known. But recently, physicists have found thousands of materials that are likely to have topological properties. They were identified based on algorithms that use their chemistry and symmetry to calculate the properties. The symmetries and the directions tell where and how electrons move in a crystal structure, predict how the electrons will behave, and thus identify whether a material is topological. Topological materials have uncommon features. They don’t change easily, meaning they’re stable to temperature fluctuations and physical distortions. Also, some topological insulators consist mostly of insulating materials but their surfaces are great conductors. The physicists are looking forward to the practical applications that would be made possible due to these newly found topological materials with these unusual properties. Although what we have now are still predictions, soon they will be tested and identified whether or not they are topological. Before reading this article, I thought the materials we have now are the only ones we will have in the future. But now I know that more materials such as topological materials are being found, that could be practical and possibly allow a breakthrough in science. But when I was reading, I kind of thought that the author just laying out the positive aspects of these new findings. They still need to be experimented to be finally identified topological, and there are possible drawbacks. For instance, they haven’t found a topological insulator that’s easy to grow and non-toxic. There still needs to be more steps taken in order for the materials to be practical. However, if the physicists keep on researching and experimenting to find the ideal practical solutions, I’m sure they will be greatly useful. www.scientificamerican.com/article/thousands-of-exotic-topological-materials-discovered-through-sweeping-search/ |