All articles tagged with #lhc
New LHCb results on rare B-meson decays, corroborated by CMS data, show tensions with Standard Model predictions in electroweak penguin processes, hinting at heavy new particles such as leptoquarks. While not definitive, the anomalies are growing and future LHC upgrades and larger datasets may confirm a need for new physics beyond the Standard Model.
New results from CERN’s LHCb show a rare electroweak penguin decay of B mesons that disagrees with Standard Model predictions at about four standard deviations, hinting at possible new physics. The finding is supported by earlier CMS results and comes from analyzing roughly 650 billion B decays (2011–2018). Although intriguing, it does not reach the five-sigma discovery threshold; further data and upgrades planned for the 2030s could confirm whether this points to new particles or remains a heavy overlap within the current theory.
CMS analyzed over 100 million W→μν decays from 2016 pp collisions at 13 TeV to extract mW using a highly granular, in-situ template fit of the muon pT, eta and charge distributions, aided by state-of-the-art NNLO+N3LL theory and data-driven PDFs; the result mW = 80,360.2 ± 9.9 MeV agrees with the Standard Model and helps address the prior CDF tension, with an additional W+ vs W− mass difference measurement of 57.0 ± 30.3 MeV. The analysis validates via Z-boson mass checks and a W-like mZ cross-check, and features robust muon momentum scale and hadronic recoil calibrations.
Scientists at CERN's LHCb have identified a new baryon, Xi-cc-plus, composed of two charm quarks and one down quark. Weighing about four times the mass of a proton, it offers a testbed for quantum chromodynamics and the strong force; discovered after 2023 detector upgrades, it is only the second observed baryon with two heavy quarks and has a lifetime up to six times shorter than a similar earlier baryon.
British researchers at CERN report the discovery of Xi-cc-plus, a proton-like particle four times heavier than a regular proton, found in data from the upgraded LHCb detector after a 20-year search, promising new insights into the strong force that binds atomic nuclei.
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.