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

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.

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.

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.

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.

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.

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

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.

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).

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%.

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

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.

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.

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.

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.

The ATLAS Collaboration has released two new studies of the tau lepton, investigating whether this elementary particle may actually be composite in nature.

The winter conference season has begun! This month, all roads lead to La Thuile in the Italian Alps, where experimental physicists and theorists will take part in some of the most important particle physics meetings of the year. The La Thuile and Rencontres de Moriond conferences promise not to disappoint, with topical sessions ranging from heavy-ion and neutrino physics, to dark matter searches and astroparticle observations.

Kevin Einsweiler is a senior scientist at Lawrence Berkeley National Lab (LBNL). He joined the ATLAS Collaboration in 1993, playing an instrumental role in bringing US institutes into the LHC programme. He served as ATLAS Pixel Project Leader (2005-2009), Physics Coordinator (2011-2013) and Upgrade Coordinator (2014-2019).

The ATLAS Collaboration at CERN welcomes a new management team at its helm. Spokesperson Andreas Hoecker (CERN) will continue to steer the experiment until March 2025.

Behind nearly every great ATLAS result lies an outstanding PhD student! Students are a key cohort of the ATLAS Collaboration, making critical contributions to the experiment while working on their degree. Every year, the Collaboration comes together to celebrate their work in the context of the ATLAS Thesis Awards.

The ATLAS Collaboration has just released its most precise luminosity measurement to date. They studied four years of measurements (2015-2018), covering the entire Run 2 of the LHC to assess the amount of luminosity delivered to the ATLAS experiment.

Stefan Guindon, Christian Ohm and Caterina Vernieri describe the major ‘Phase II’ upgrades taking place to prepare the ATLAS detector for the High-Luminosity LHC.

The ATLAS Collaboration has performed an extensive search for new, high-mass particles that can decay to a pair of W bosons. As many theoretical models predict the existence of such high-mass particles, physicists were able to investigate the validity of several models at once across a large energy range.

The ATLAS Collaboration has just released its first Run 3 measurements, studying data collected in the first half of August 2022. Researchers have measured the interaction strength (or cross-section) of two well-known processes: the production of a pair of top quarks and the production of a Z boson.

In a highlight result presented at the Higgs 2022 conference, the ATLAS Collaboration studied the production of off-shell Higgs bosons with a high invariant mass decaying into two on-shell Z bosons using the data collected during LHC Run 2 (2015-2018). For their new search, ATLAS physicists focused on events where the two Z bosons decay into four charged leptons (ZZ→4l channel) or two charged leptons plus two neutrinos (ZZ→ 2l2v channel), as they offered the highest signal sensitivity.