ATLAS hunts for new physics in the scattering of W bosons

Vector boson scattering processes play a special role within the Standard Model, as they are closely related to the Higgs mechanism and can proceed via an exchange of a Higgs boson. By studying these processes, ATLAS physicists are exploring multiple new-physics models, including anomalous self-interactions of the W bosons and extended Higgs sector with additional Higgs bosons.

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Machine learning is revolutionising our understanding of particle “jets”

This week, ATLAS physicists presented four exciting new results about jet tagging using AI algorithms at the BOOST 2023 conference held at Lawrence Berkeley National Lab (USA).

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Signal and noise

The ATLAS Collaboration has released two new results explaining how detector timing measurements and calorimeter signal calibration using artificial intelligence (AI) are being used to further improve the quality of data recorded by the experiment.

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Summary of new ATLAS results from BOOST 2023

The 15th International Workshop on Boosted Object Phenomenology, Reconstruction, Measurements, and Searches at Colliders (BOOST 2023) kicks off today in Lawrence Berkeley National Lab, California (USA). The conference brings together experts from the LHC experiments and the theory community to discuss new approaches for using “jets” of particles in studies of Quantum Chromodynamics (QCD) and searches physics beyond the Standard Model.

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ATLAS sets record precision on Higgs boson’s mass

The new result is the most precise determination of the Higgs-boson mass yet, achieving a remarkable accuracy of 0.09% for this fundamental parameter.

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ATLAS measures Higgs boson mass with unprecedented precision

This week, at the Lepton-Photon Conference in Melbourne (Australia), the ATLAS Collaboration presented its measurement of the Higgs-boson mass in studies of Higgs decays to two photons using the full LHC Run 2 dataset (“H→yy” or the diphoton channel), and a new combination of this measurement with the 2022 measurement of the Higgs-boson mass in studies of the Higgs decays to four leptons (the “H→4l channel”).

Physics Briefing |

Summary of new ATLAS results from 2023 summer conferences

The summer conference season is here! While for some, summer means slowing down – for ATLAS researchers, it means the start of new conferences, with more new results to be presented! This season, experimental physics and theorists will be traveling to Melbourne, Australia, for the International Symposium on Lepton Photon Interactions at High Energies (Lepton Photon), and to Hamburg, Germany, for the European Physical Society Conference on High Energy Physics ( EPS-HEP).

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Giving collisions a new shape

When studying the shape of LHC collision events, physicists ask: how similar or different is their energy flow? The ATLAS Collaboration recently published a measurement of new collision event shapes in high-energy multijet events at the LHC.

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ATLAS highlights from LHCP 2023

Over 300 physicists travelled to Belgrade (Serbia) for LHCP’s long-awaited return to in-person gatherings. Scientists from the ATLAS Collaboration presented several new results at the LHCP conference. These newly released results cover a broad range of physics topics, including precision measurements of the W± and Z bosons, evidence of the Higgs-boson decay into a Z boson and a photon, and searches for a new scalar particle.

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Not a jet all the way: is dark matter hiding in plain sight?

What happens if dark-matter particles are produced inside a jet of Standard-Model particles? This leads to a novel detector signature known as semi-visible jets! The ATLAS Collaboration has come up with a new search for semi-visible jets, looking for them in a general production mode where two protons interact by exchanging an intermediate particle, which is then converted into two jets.

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LHC experiments see first evidence for rare Higgs boson decay into two different bosons

The ATLAS and CMS Collaborations have joined forces to report first evidence of the Higgs boson decaying into a Z boson and a photon.

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LHC experiments see first evidence of a rare Higgs boson decay

ATLAS and CMS teamed up to find the first evidence of the rare process in which the Higgs boson decays into a Z boson, the electrically neutral carrier of the weak force, and a photon, the carrier of the electromagnetic force.

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New high-precision measurements of W and Z boson properties

At the 2023 LHCP conference, ATLAS physicists presented precise new measurements of the W± and Z boson transverse momentum distributions at two centre-of-mass energies: 13 TeV and, for the first time, 5.02 TeV. These results give unprecedented information on these transverse-momentum shape spectra, providing crucial input for other studies of these bosons.

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ATLAS measures the Higgs boson at 13.6 TeV

The ATLAS Collaboration just released new measurements of the production rate (or cross-section) of Higgs bosons at 13.6 TeV using data collected in the second half of 2022.

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Summary of new ATLAS results from LHCP 2023

The eleventh annual conference on Large Hadron Collider physics (LHCP 2023) kicks off today in Belgrade (Serbia) signaling the return of this week-long event to its face-to-face format. The programme of this edition covers the wide spectrum of Large Hadron Collider physics and technology, from several final studies of the LHC Run-2 dataset (2015-2018) to detailed assessments of the upgraded accelerators and detectors for Run 3.

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ATLAS Live: Behind the Scenes at the Control Room

On 5 May at 4pm CEST, ATLAS physicists Dr. Stefanie Morgenstern and Dr. Liaoshan Shi will give a live tour of the ATLAS Control Room on the ATLAS and CERN Youtube Channels.

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ATLAS highlights from the Moriond 2023 conference

ATLAS researchers presented several new results at the recent Rencontres de Moriond conference, spanning over a decade of LHC data.

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ATLAS & CMS Physicists Recover Lost Higgs Boson

Scientists working on the Large Hadron Collider at CERN breathed a sigh of relief today, as the world-renowned Higgs boson returned to its showcase in the heart of the laboratory.

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Probing fundamental symmetries of nature with the Higgs boson

In the new results presented at the Moriond conferences, the ATLAS Collaboration tested the CP invariance of Higgs-boson interactions with vector bosons (W or Z bosons).

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LHC passes a new milestone

The ATLAS Collaboration has just published the most precise measurement to date of the production cross section of top-quark pairs. The measured value is 829 ± 15 picobarns and has a relative uncertainty of just 1.8%.

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ATLAS confirms mild tension in production of top-quark pairs with a W boson

The ATLAS Collaboration has released the most detailed analysis to date of the production of top-quark pairs alongside a W boson.

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ATLAS observes the simultaneous production of four top quarks

The ATLAS Collaboration at CERN announces the observation of the simultaneous production of four top quarks. This is one of the rarest – and heaviest – processes ever observed at the Large Hadron Collider (LHC), with a total particle mass of almost 700 GeV.

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ATLAS measures the strength of the strong force

The ATLAS Collaboration at CERN has released a precise new measurement of the Z-boson transverse momentum. This has allowed researchers to determine the strength of the strong force. Their result has less than 1% uncertainty, making it the most precise determination of the strong force ever made by a single experiment.

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New ATLAS result weighs in on the W boson

The ATLAS Collaboration has measured the W boson mass to be 80360 MeV with an uncertainty of 16 MeV – in agreement with the Standard Model.

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Searching from top to bottom for lepton unity

The ATLAS Collaboration has released an impressive set of searches for leptoquarks interacting with third-generation leptons or quarks – placing valuable constraints on leptoquark parameters.

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