Latest news with #particlePhysics
Arab News
25-06-2025
- Science
- Arab News
What We Are Reading Today: ‘The Standard Model'
Authors: Yuval Grossman and Yossi Nir 'The Standard Model' is an elegant and extremely successful theory that formulates the laws of fundamental interactions among elementary particles. This incisive textbook introduces students to the physics of the Standard Model while providing an essential overview of modern particle physics, with a unique emphasis on symmetry principles as the starting point for constructing models. 'The Standard Model' equips students with an in-depth understanding of this impressively predictive theory.
Yahoo
18-06-2025
- Science
- Yahoo
Bizarre radio signals that defy physics detected under Antarctica
When you buy through links on our articles, Future and its syndication partners may earn a commission. Instruments flying more than 18 miles (29 kilometers) above Antarctica detected two unexplainable radio pulses coming from below the ice — and these signals seem to defy particle physics. Researchers determined the radio pulses came from angles around 30 degrees below Antarctica's surface, which the laws of physics theoretically prohibit. Calculations suggest the signals had to pass through thousands of miles of rock to get to the surface; however, scientists expect the pulses to be absorbed by the rock on this journey, rendering them undetectable. The research team is now looking deeper into what could have caused the unexpected pulses. They ruled out some possible explanations using the Pierre Auger Observatory in Argentina and shared those findings in a study published March 27 in the journal Physical Review Letters. "It's an interesting problem because we still don't actually have an explanation for what those anomalies are," Stephanie Wissel, a particle physicist and co-author of the study, said in a statement. The mysterious pulses were first detected by the Antarctic Impulsive Transient Antenna (ANITA) experiment. ANITA comprises 24 radio antennas attached to a NASA balloon, located near the south pole to avoid signal interference. Related: Antimatter detected on International Space Station could reveal new physics The project was designed to capture data about neutrinos — subatomic particles that are especially difficult to study because they lack electric charge and have minimal mass. These elusive characteristics have earned them the nickname "ghost particles". But the confusing radio signals are "most likely not representing neutrinos," Wissel said. Existing models, she explained, predict that pulses caused by neutrinos would originate from angles very far from 30 degrees under the surface. The new study provides further evidence that neutrinos are probably not involved. Using complex mathematical models and simulations, the research team also ruled out noise and known particle interactions as sources of the signals. They even examined data from other experiments to see if they observed any interaction that could cause the pulses, to no avail. Since these observations can't be explained by the Standard Model, the theory that describes subatomic particles, the phenomenon responsible for these pulses could be key to unlocking new scientific understanding. "More research needs to be done on this," Benjamin Flaggs, a physics graduate student at the University of Delaware and co-author of the study, told Live Science. "There are theorists proposing some beyond-standard-model interactions from different types of particles," he said. If neutrinos aren't responsible for the radio signals, then what is? Some theories suggest the signals are coming from dark matter — the invisible entity that makes up about 27% of the universe, but which remains poorly understood — Wissel said. But more data is needed before coming to any meaningful conclusion. Wissel favors the theory that the origin of these pulses may be explained by some as-of-yet unknown behavior of radio waves, but there's no evidence to support this guess, either. "So, right now, it's one of these long-standing mysteries," she said. RELATED STORIES —Mysterious particles spewing from Antarctica defy physics —Monster antimatter particle slams into Antarctica —Bizarre Particles Keep Flying Out of Antarctica's Ice, and They Might Shatter Modern Physics The Payload for Ultrahigh Energy Observations, a new balloon-based instrument, with advanced levels of sensitivity, is expected to help solve this puzzle by detecting more anomalies, thus providing more data to be scrutinized. "The more data we can get, the better we can get our statistical error," Flaggs said. The instrument will launch from Antarctica in December. "We haven't discovered everything yet," Flaggs added. "It's exciting for researchers because these are problems that no one else has figured out before."
Yahoo
31-05-2025
- Business
- Yahoo
Infamous 'neutron lifetime puzzle' may finally have a solution — but it involves invisible atoms
When you buy through links on our articles, Future and its syndication partners may earn a commission. A mysterious second flavor of hydrogen atoms — one that doesn't interact with light — may exist, a new theoretical study proposes, and it could account for much of the universe's missing matter while also explaining a long-standing mystery in particle physics. The mystery, known as the neutron lifetime puzzle, revolves around two experimental methods whose results disagree on the average lifetime of free neutrons — those not bound within atomic nuclei — before they decay to produce three other particles: protons, electrons and neutrinos. "There were two kinds of experiments for measuring the neutron lifetime," Eugene Oks, a physicist at Auburn University and sole author of the new study published in the journal Nuclear Physics B, told Live Science in an email. The two methods are called beam and bottle. In beam experiments, scientists count protons left behind immediately after neutrons decay. Using the other approach, in bottle experiments, ultra-cold neutrons are trapped and left to decay, and the remaining neutrons are counted after the experimental run is over — typically lasting between 100 and 1000 seconds, with many such runs performed under varying conditions like trap material, storage time, and temperature to improve accuracy and control for systematic errors. These two methods yield results that differ by about 10 seconds: beam experiments measure a neutron lifetime of 888 seconds, whereas bottle experiments report 878 seconds — a discrepancy well beyond experimental uncertainty. "This was the puzzle," said Oks. In his study, Oks proposes that the discrepancy in lifetimes arises because a neutron sometimes decays not into three particles, but just two: a hydrogen atom and a neutrino. Since the hydrogen atom is electrically neutral, it can pass through detectors unnoticed, giving the false impression that fewer decays have occurred than expected. Although this two-body decay mode had been proposed theoretically in the past, it was believed to be extremely rare — occurring in only about 4 out of every million decays. Oks argues that this estimate is dramatically off because previous calculations didn't consider a more exotic possibility: that most of these two-body decays produce a second, unrecognized flavor of hydrogen atom. And unlike ordinary hydrogen, these atoms don't interact with light. "They do not emit or absorb electromagnetic radiation, they remain dark," Oks explained. That would make them undetectable using traditional instruments, which rely on light to find and study atoms. Related: How many atoms are in the observable universe? What distinguishes this second flavor? Most importantly, the electron in this type of hydrogen would be far more likely to be found close to the central proton than in ordinary atoms, and would be completely immune to the electromagnetic forces that make regular atoms visible. The invisible hydrogen would be hard to detect. "The probability of finding the atomic electron in the close proximity to the proton is several orders of magnitude greater than for ordinary hydrogen atoms," Oks added. This strange atomic behavior comes from a peculiar solution to the Dirac equation — the core equation in quantum physics that describes how electrons behave. Normally, these solutions are considered unphysical, but Oks argues that once the fact that protons have a finite size is taken into account, these unusual solutions start to make sense and describe well-defined particles. By considering a second flavor of hydrogen, Oks calculates that the rate of two-body decays could be enhanced by a factor of about 3,000. This would raise their frequency to around 1% of all neutron decays — enough to explain the gap between beam and bottle experiments. "The enhancement of the two-body decay by a factor of about 3000 provided the complete quantitative resolution of the neutron lifetime puzzle," he said. That's not all. Invisible hydrogen atoms might also solve another cosmic mystery: the identity of dark matter, the unseen material that's thought to make up most of the matter in the universe today. In a 2020 study, Oks showed that if these invisible atoms were abundant in the early universe, they could explain an unexpected dip in ancient hydrogen radio signals observed by astronomers. Since then, he has argued that these atoms may be the dominant form of baryonic dark matter — matter made from known particles like protons and neutrons, but in a form that's hard to detect. "The status of the second flavor of hydrogen atoms as baryonic dark matter is favored by the Occam's razor principle," said Oks, referring to the idea that the simplest explanation is often best. "The second flavor of hydrogen atoms, being based on the standard quantum mechanics, does not go beyond the Standard Model of particle physics." In other words, no exotic new particles or material are needed to explain dark matter — just a new interpretation of atoms that we already thought we understood. Oks is now collaborating with experimentalists to test his theory. At the Los Alamos National Laboratory in New Mexico, a team is preparing an experiment based on two key ideas. First, both flavors of hydrogen can be excited using an electron beam. Second, once excited, ordinary hydrogen atoms can be stripped away using a laser or electric field — leaving behind only the invisible ones. A similar experiment is also being prepared in Germany at the Forschungszentrum Jülich, a national research institute near Garching. RELATED STORIES —Dark matter may have its own 'invisible' periodic table of elements —Scientists may have finally found where the 'missing half' of the universe's matter is hiding —Scientists are one step closer to knowing the mass of ghostly neutrinos — possibly paving the way to new physics The stakes for these tests are high. "If successful, the experiment could yield results this year," said Oks. "The success would be a very significant breakthrough both in particle physics and in dark matter research." In the future, Oks plans to explore whether other atomic systems might also have two flavors, potentially opening the door to even more surprising discoveries. And if confirmed, such findings could also reshape our understanding of cosmic history. "The precise value of the neutron lifetime is pivotal for calculating the amount of hydrogen, helium and other light elements that were formed in the first few minutes of the universe's life," Oks said. So his proposal doesn't just solve a long-standing puzzle — it could rewrite the earliest chapters of cosmic evolution.
