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An unforeseen feature in proton-proton collisions previously observed by the CMS experiment at CERN's Large Hadron Collider (LHC) has now been confirmed by its sister experiment ATLAS. The result, reported yesterday at the European Physical Society's High-Energy Physics conference in Marseille, suggests that top quarks - the heaviest and shortest-lived of all the elementary particles - can momentarily pair up with their antimatter counterparts to produce a "quasi-bound-state" called toponium.

In a paper published today in the journal Nature , the CLOUD collaboration at CERN reveals a new source of atmospheric aerosol particles that could help scientists to refine climate models. Aerosols are microscopic particles suspended in the atmosphere that arise from both natural sources and human activities.

Geneva, 25 September 2024. At a seminar held at CERN this week, the NA62 collaboration reported the unequivocal confirmation of the ultra-rare decay of a positively charged kaon into a positively charged pion and a neutrino-antineutrino pair. Experiments including NA62 have previously measured and seen evidence of this process, but this is the first time it has been measured with a statistical significance of five standard deviations , crossing the threshold traditionally required to claim a discovery in particle physics.

The experiment at CERN is the latest to weigh in on the mass of the W boson - an elementary particle that, along with the Z boson , mediates the weak force, which is responsible for a form of radioactivity and initiates the nuclear fusion reaction that powers the Sun. At a seminar held at CERN today, the CMS collaboration reported how it has analysed proton-proton collision data from the second run of the Large Hadron Collider , the Laboratory's flagship particle accelerator, to make its first mass measurement of this fundamental particle.

Last week, at the annual Rencontres de Moriond conference, the CMS collaboration presented a measurement of the effective leptonic electroweak mixing angle. The result is the most precise measurement performed at a hadron collider to date and is in good agreement with the prediction from the Standard Model.

Isaac Newton's historic work on gravity was apparently inspired by watching an apple fall to the ground from a tree. But what about an "anti-apple" made of antimatter , would it fall in the same way if it existed? According to Albert Einstein's much-tested theory of general relativity, the modern theory of gravity, antimatter and matter should fall to Earth in the same way.

CERN At CERN, we probe the fundamental structure of particles that make up everything around us. We do so using the world's largest and most complex scientific instruments. Know more Key achievements submenu The Higgs Boson Press Room submenu Geneva, 23 March 2023. The W boson , a fundamental particle that carries the charged weak force, is the subject of a new precision measurement of its mass by the ATLAS experiment at CERN.

Geneva, 31 March 2021. The ALPHA collaboration at CERN has succeeded in cooling down antihydrogen atoms - the simplest form of atomic antimatter - using laser light. The technique, known as laser cooling, was first demonstrated 40 years ago on normal matter and is a mainstay of many research fields.

Geneva. At the 40th ICHEP conference , the ATLAS and CMS experiments announced new results which show that the Higgs boson decays into two muons. The muon is a heavier copy of the electron, one of the elementary particles that constitute the matter content of the Universe. While electrons are classified as a first-generation particle, muons belong to the second generation.

The LHCb collaboration at CERN 1 has seen, for the first time, the matter-antimatter asymmetry known as CP violation in a particle dubbed the D0 meson. The finding, presented today at the annual Rencontres de Moriond conference and in a dedicated CERN seminar , is sure to make it into the textbooks of particle physics.

Geneva. Today, the Future Circular Collider (FCC) collaboration submitted its Conceptual Design Report (CDR) for publication, a four-volume document that presents the different options for a large circular collider of the future. It showcases the great physics opportunities offered by machines of unprecedented energy and intensity and describes the technical challenges, cost and schedule for realisation.

Geneva, 3 December 2018. Early this morning, operators of the CERN Control Centre turned off the Large Hadron Collider (LHC), ending the very successful second run of the world's most powerful particle accelerator. CERN's accelerator complex will be stopped for about two years to enable major upgrade and renovation works.

Geneva 1 st October 2018. An unprecedented combination of experimental nuclear physics and theoretical and computational modelling techniques has been brought together to reveal the full extent of the odd-even shape staggering of exotic mercury isotopes, and explain how it happens. The result, from an international team at the ISOLDE nuclear physics facility at CERN 1 , published today , demonstrates and explains a phenomenon unique to mercury isotopes where the shape of the atomic nuclei dramatically moves between a football and rugby ball.

Geneva, 18 September 2018. The largest liquid-argon neutrino detector in the world has just recorded its first particle tracks, signaling the start of a new chapter in the story of the international Deep Underground Neutrino Experiment (DUNE). DUNE's scientific mission is dedicated to unlocking the mysteries of neutrinos, the most abundant (and most mysterious) matter particles in the universe.

Geneva, 29 August 2018. In a paper published today in the journal Nature , the AWAKE collaboration at CERN reports the first ever successful acceleration of electrons using a wave generated by protons zipping through a plasma. The acceleration obtained over a given distance is already several times higher than that of conventional technologies currently available for particle accelerators.

Geneva, 28 August. Six years after its discovery, the Higgs boson has at last been observed decaying to fundamental particles known as bottom quarks. The finding, presented today at CERN 1 by the ATLAS and CMS collaborations at the Large Hadron Collider (LHC), is consistent with the hypothesis that the all-pervading quantum field behind the Higgs boson also gives mass to the bottom quark.

Three years after the announcement of the discovery of a new particle, the so-called Higgs boson, the ATLAS and CMS Collaborations present for the first time combined measurements of many of its properties, at the third annual Large Hadron Collider Physics Conference (LHCP 2015). By combining their analyses of the data collected in 2011 and 2012, ATLAS and CMS draw the sharpest picture yet of this novel boson.

The ALICE experiment at the Large Hadron Collider (LHC) at CERN has made a precise measurement of the difference between ratios of the mass and electric charge of light nuclei and antinuclei. The result, published today , confirms a fundamental symmetry of nature to an unprecedented precision for light nuclei.

The Baryon Antibaryon Symmetry Experiment (BASE ) at CERN 2 's Antiproton Decelerator (AD), reports the most precise comparison of the charge-to-mass ratio of the proton to that of its antimatter equivalent, the antiproton. The charge-to-mass ratio - an important property of particles - can be measured by observing the oscillation of a particle in a magnetic field.

LHCb experiment at CERN's Large Hadron Collider has reported the discovery of a class of particles known as pentaquarks. "The pentaquark is not just any new particle," said LHCb spokesperson Guy Wilkinson. " It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches .