All posts tagged: particle physics

Future Circular Collider public consultations begin across Switzerland and France

Future Circular Collider public consultations begin across Switzerland and France

Published by skeptic

The public consultation phase for CERN’s proposed Future Circular Collider project has begun in Switzerland and France, marking a major step in the long-running evaluation of what could become the world’s largest particle physics facility. The consultations will run between May and October 2026 and are intended to gather public feedback before any final approval decision is made. CERN confirmed that the Future Circular Collider remains under study, with a formal decision on whether to proceed not expected before 2028. The project is currently being assessed as part of the wider update to the European Strategy for Particle Physics, which guides the continent’s long-term research priorities. If approved, the Future Circular Collider would be built in a 91-kilometre underground tunnel beneath parts of eastern France and western Switzerland. Scientists say the machine could unlock new insights into the structure of matter and the origins of the Universe, while also driving advances in engineering, computing and energy technologies. What is the Future Circular Collider? The proposed Future Circular Collider, often referred to as the FCC, would …

300-year-old experiment could become world’s best dark matter detector

300-year-old experiment could become world’s best dark matter detector

Published by skeptic

Dark matter makes up more of our universe than ordinary matter ESA/Euclid/Euclid Consortium/NASA, image processing by M. Schirmer (MPIA, Heidelberg) A centuries-old experiment could help accelerate the search for new and exotic particles, including those that make up dark matter. In 1773, British scientist Henry Cavendish set up a simple experiment aimed at uncovering the nature of electromagnetism. It involved measuring the electric potential at the surface of two nested metal shells to discern how charged particles affect each other within them. Now, Peter Graham at Stanford University in California and his colleagues say that reviving Cavendish’s experiment could help reveal an even more mysterious feature of our cosmos – the particles that make up dark matter. Though dark matter comprises much more of our cosmos than the ordinary matter, we don’t know what it is made of. There are many theoretical proposals for what it could be, and experiments trying to find out range from using particle colliders to elaborate underground detectors. Graham and his colleagues focused on one dark matter candidate called millicharged …

Decade-long muon calculation shrinks hope for a fifth force of nature

Decade-long muon calculation shrinks hope for a fifth force of nature

Published by Jenni Sidey

For years, one tiny mismatch in particle physics carried outsized hopes. The muon, a heavier and short-lived cousin of the electron, seemed to wobble in a magnetic field just a little differently than the Standard Model said it should. That gap, known through the particle’s anomalous magnetic moment or muon g−2, looked to many physicists like a possible opening to something deeper, perhaps even a fifth force of nature. Now that opening looks much narrower. An international team led by Penn State physicist Zoltan Fodor has published what it describes as the most precise calculation yet of the key strong-force contribution behind the muon’s magnetic behavior. Their result, published in Nature, brings theory and experiment into agreement within half a standard deviation, suggesting the long-running discrepancy was not a sign of new physics after all. Artist’s conception of the mystery of the magnetic moment of the muon — a sub-atomic particle similar to, but heavier than, an electron (represented by the Greek letter mu). (CREDIT: Dani Zemba / Penn State) New calculation method “There were …

Undergraduate students built a cavity detector to search for axion dark matter

Undergraduate students built a cavity detector to search for axion dark matter

Published by Jenni Sidey

Dark matter is supposed to be everywhere, threaded through the Milky Way and outnumbering ordinary matter by a wide margin. Yet after decades of effort, nobody has caught it directly. That gap between certainty and absence has helped turn modern cosmology into a field of giant machines, giant budgets and giant collaborations. So there is something striking about a recent axion search that went in the opposite direction. A team of then-undergraduate students at the University of Hamburg built a compact cavity detector. They ran it inside a powerful magnet and used it to probe one narrow slice of the dark matter problem. They did not find a signal. However, what they did find was a way to rule out axions with certain properties in that range. This tightened the map for future searches and showed that careful, smaller-scale physics can still leave a mark on one of science’s biggest mysteries. The work, now published in the Journal of Cosmology and Astroparticle Physics, focused on axions, hypothetical particles long considered one of the strongest candidates …

Physicists achieve most accurate measurement yet of the W boson

Physicists achieve most accurate measurement yet of the W boson

Published by Jenni Sidey

For a few years, one of particle physics’ most unsettling numbers seemed to be pointing somewhere strange. The trouble centered on the W boson, a heavy particle that carries the weak force, one of the four fundamental forces in nature. That force helps particles switch identities, letting protons turn into neutrons and back again. It sits behind radioactive decay and helps make nuclear fusion in the sun possible. Then came a jolt in 2022. A measurement from the Collider Detector at Fermilab, or CDF, put the W boson’s mass noticeably above what the Standard Model of particle physics said it should be. Because the Standard Model is the field’s best-tested framework for matter and forces, the result stirred talk of hidden particles, unknown forces, and a crack in the theory itself. Now a new measurement from the CMS experiment at CERN’s Large Hadron Collider points the other way. In a paper published in Nature, the CMS Collaboration reports that the W boson has a mass of 80,360.2 ± 9.9 megaelectron volts, a figure that lines …

The coldest ever hunt for dark matter has begun deep underground

The coldest ever hunt for dark matter has begun deep underground

Published by Jenni Sidey

Two kilometres underground near Sudbury, Ont., a machine has reached a temperature so low it barely seems real. Inside SNOLAB, scientists have cooled the Super Cryogenic Dark Matter Search, or SuperCDMS, to just tens of milliKelvin above absolute zero, roughly a hundred times colder than outer space. That number matters because the experiment’s detectors cannot truly come alive until they reach it. “Reaching this base temperature now allows us to turn on the detectors, make sure they are all working and start collecting data that potentially is coming from dark matter particles hitting our detectors,” says Miriam Diamond, a co-principal investigator in the international collaboration and an assistant professor in the University of Toronto’s department of physics in the Faculty of Arts & Science. For the team behind SuperCDMS, hitting base temperature marks a turning point. The project is no longer mainly about construction and installation. It is moving into commissioning and, soon after that, science operations. Scientists have reached a critical milestone in their efforts to detect dark matter – the mysterious substance that …

Astronomers discover a mysterious duality in dark matter

Astronomers discover a mysterious duality in dark matter

Published by Jenni Sidey

A dark matter signal that appears in one place but not another might look like a contradiction. This new study argues it may be something else entirely. At the center of the Milky Way, astronomers have long seen an excess of gamma rays, a form of high-energy light. That glow, known as the Galactic Center Gamma-Ray Excess, has remained one of the more intriguing clues in the hunt for dark matter. Some researchers think it could come from dark matter particles annihilating each other. Others argue it may come from more ordinary sources. In particular, they suggest a large population of faint millisecond pulsars could be responsible. A paper published in the Journal of Cosmology and Astroparticle Physics takes aim at one of the strongest objections to the dark matter idea. If dark matter is causing the gamma-ray excess near the Milky Way’s center, then why do dwarf galaxies, which are also packed with dark matter, not show the same kind of signal? According to the authors, that absence does not necessarily sink the dark …

Astronomers discover a mysterious duality in dark matter

Astronomers discover a mysterious duality in dark matter

Published by Jenni Sidey

A dark matter signal that appears in one place but not another might look like a contradiction. This new study argues it may be something else entirely. At the center of the Milky Way, astronomers have long seen an excess of gamma rays, a form of high-energy light. That glow, known as the Galactic Center Gamma-Ray Excess, has remained one of the more intriguing clues in the hunt for dark matter. Some researchers think it could come from dark matter particles annihilating each other. Others argue it may come from more ordinary sources. In particular, they suggest a large population of faint millisecond pulsars could be responsible. A paper published in the Journal of Cosmology and Astroparticle Physics takes aim at one of the strongest objections to the dark matter idea. If dark matter is causing the gamma-ray excess near the Milky Way’s center, then why do dwarf galaxies, which are also packed with dark matter, not show the same kind of signal? According to the authors, that absence does not necessarily sink the dark …

We might finally know the size of the proton

We might finally know the size of the proton

Published by skeptic

A vacuum chamber used to measure electron transitions in atomic hydrogen, from which the proton’s size was inferred Axel Beyer/MPQ At long last, we have pinned down the size of a proton. More than 15 years after an experiment unexpectedly shook the world of particle physics, researchers are regaining their grip on one of this fundamental particle’s most basic properties. Look around you, and everything you see will be filled with protons. The proton is a fundamental building block of our world – and until 2010, we thought we understood it fairly well. We knew its composition – it is made from three quarks – and we knew its size. Then, a measurement based on an exotic hydrogen atom showed that the proton may actually be about 4 per cent smaller than expected. Physicists scrambled, exploring sources of experimental error as well as theories about new physics phenomena that could resolve this “proton radius puzzle”. In 2019, another experiment strengthened the evidence that the proton’s size had long been overestimated. Now, the issue may have …

Astronomers discover a mysterious duality in dark matter

What if dark matter came in two states?

Published by Jenni Sidey

The absence of a signal could itself be a signal. This is the idea behind a new study published in the Journal of Cosmology and Astroparticle Physics (JCAP), which aims to redefine how we search for dark matter, showing that it may not be necessary to find the same “clues” everywhere in order to interpret it. In particular, the study suggests that even if we observe a certain type of signal at the center of our galaxy — an excess of gamma radiation that could result from the annihilation of dark matter particles — failing to detect the same signal in other systems, such as dwarf galaxies, is not enough to rule out this explanation. Dark matter, in fact, may not consist of a single particle, but of multiple slightly different components, whose behavior varies depending on the cosmic environment. The galactic center gamma-ray excess Dark matter: we know it exists and is abundant, but we have never observed it directly and therefore we still do not know what it is. For decades, it has been …