All articles tagged with #lhc
At the LHC's ALICE experiment, ultraperipheral lead-208 collisions produce gold-205 briefly via photon exchange, with a cross section near 6.8 barns and a lifetime of about 1e-23 seconds. This clean, photon-driven process lets physicists probe nuclear structure and QED at high energy and informs future collider design.
Physicists at the Large Hadron Collider recreated brief, Big-Bang–like conditions by colliding heavy nuclei, forming a droplet of quark-gluon plasma that behaves more like a liquid than a gas. By tagging quarks with Z bosons, researchers observed a tiny wake and a sub-percent dip in particle production, indicating energy transfer to the plasma and opening new avenues to study the primordial state of matter, as reported in Physics Letters B.
Using the Large Hadron Collider, researchers recreated quark‑gluon plasma and observed that the ultra‑hot primordial soup behaved as a nearly perfect liquid, producing wakes as fast‑moving quarks traversed it. By tagging events with a Z‑boson to isolate single-quark wakes, they found fluid‑like ripples that match hybrid model predictions, offering new insight into the universe’s first microseconds and the properties of the quark‑gluon plasma (Physics Letters B).
More than a decade after the Higgs discovery, particle physics has yet to find new physics beyond the Standard Model, prompting a crisis about the field’s direction. Proposals for big next-gen machines (the Future Circular Collider, muon colliders) and smaller-scale tests (axions, hidden valleys) mingle with advances in AI-assisted data analysis, but there’s no discovery guarantee and talent is drifting toward other fields. In short, particle physics isn’t dead, but it’s hard—and the path forward remains uncertain.
CERN has secured $1 billion in private donations from the Breakthrough Prize Foundation, the Eric and Wendy Schmidt Fund, John Elkann, and Xavier Niel to kick off the Future Circular Collider (FCC), a 90.7-km tunnel intended as the Large Hadron Collider’s successor. The plan features a two-phase roadmap: FCC-ee as a Higgs factory starting around 2030 with operations by 2047, followed by FCC-hh protons at 85 TeV in the 2070s to probe new physics. A CERN Council decision is expected in 2028, with construction potentially starting in 2030. China’s CEPC stall may open collaboration opportunities modeled after ITER, while the HL-LHC upgrade remains a priority in the near term.
The Large Hadron Collider is being upgraded to reach extreme cryogenic temperatures to improve measurements and reduce electronic noise. A new CO2-based heat exchanger, developed with Swep, cools Atlas components to -45C, while other accelerator sections reach 1.9 Kelvin for superconducting magnets. This relies on dilution refrigeration using helium-4 and helium-3, a key tech for quantum computing, with broader applications in cryogenic cooling for semiconductors and even supermarket refrigeration. By achieving colder conditions, scientists aim to probe physics beyond the Standard Model.
Scientists at CERN have successfully observed double crystal channeling at the LHC, a novel technique that could enable more precise measurements of short-lived particles like charm baryons, potentially opening new avenues in the search for physics beyond the Standard Model.
The article discusses the current state and future prospects of particle colliders for studying the Higgs boson, highlighting the potential of a cost-effective and faster option called LEP3, which would repurpose existing infrastructure to produce large numbers of Higgs particles for detailed study, as an alternative to more expensive and longer-term projects like the Future Circular Collider.
Researchers at CERN's LHC, through CMS and ATLAS experiments, have observed a fleeting bound state of top quark and antiquark pairs, called toponium, challenging previous assumptions about the top quark's behavior and opening new avenues for understanding the strong nuclear force and potential new particles.
A graduate student developed a new machine learning method called Neural Simulation-Based Inference to better analyze data from the Large Hadron Collider, overcoming challenges posed by quantum interference, leading to more precise measurements of the Higgs boson and impacting future research plans.
In 2012, CERN's Large Hadron Collider achieved the creation of the hottest artificially produced temperature ever, reaching 5 trillion Kelvin, which is about 100,000 times hotter than the Sun's core and similar to conditions microseconds after the Big Bang, by colliding lead ions at near-light speeds to study primordial matter.
The ALICE collaboration at the Large Hadron Collider has found the first evidence of antihyperhelium-4, the heaviest antimatter hypernucleus observed at the LHC, with a significance of 3.5 standard deviations. This discovery, based on 2018 lead-lead collision data, supports the statistical hadronisation model's predictions and contributes to understanding the matter-antimatter asymmetry in the universe. The findings also include evidence of antihyperhydrogen-4 and confirm equal production of matter and antimatter at LHC energies.
The CMS collaboration has released the combination of measurements that led to the discovery of the Higgs boson in 2012, along with the statistical analysis tool called Combine software, which was developed during the first run of the Large Hadron Collider (LHC). This release includes a likelihood function with nearly 700 parameters, allowing researchers outside the collaboration to incorporate the CMS Higgs boson discovery measurements into their studies. This move aligns with CMS's commitment to fully open science, which also includes open-access publications, the release of CMS data on the CERN open-data portal, and the publication of its software framework on GitHub.
The ATLAS collaboration at the Large Hadron Collider (LHC) has made the first measurement of the W-boson width, a parameter that may hold clues about new physics phenomena beyond the Standard Model. The measurement, based on proton-proton collision data at an energy of 7 TeV, yielded a value of 2202 ± 47 million electronvolts (MeV), consistent with the Standard-Model prediction. This achievement required a detailed particle-momentum analysis and the confluence of high-precision results, including an accurate understanding of W-boson production, knowledge of the inner structure of the proton, and theoretical predictions. The measured values of the W-boson mass and width are consistent with the Standard-Model predictions, and future measurements using larger datasets are expected to further refine our understanding of particle physics.
The ATLAS collaboration at the Large Hadron Collider (LHC) has provided the first measurement of the W-boson width, a parameter that may hold clues about new physics phenomena. The measurement, based on proton-proton collision data, yielded a value of 2202 ± 47 MeV, consistent with the Standard-Model prediction. Achieving this precision required detailed particle-momentum analysis, accurate understanding of W-boson production, and knowledge of the inner structure of the proton. The measured values of the W-boson mass and width are consistent with the Standard-Model predictions, and future measurements using larger datasets are expected to further reduce uncertainties and enable more stringent tests of the Standard Model.