Tau & co.: the search for new physics with the heaviest leptons

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

Physics Briefing |

Summary of new ATLAS results from 2023 Winter Conferences

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.

News |

In conversation with Kevin Einsweiler, an instrumental voice in ATLAS upgrades

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).

Portrait |

ATLAS management begins new term

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.

News |

Winners of the 2022 ATLAS Thesis Awards announced

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.

News |

ATLAS delivers most precise luminosity measurement at LHC

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.

Experiment Briefing |

A new ATLAS for the high-luminosity era

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.

Feature |

ATLAS casts wide net in search for new high-mass particles

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.

Physics Briefing |

ATLAS moves into top gear for Run 3

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.

Physics Briefing |

ATLAS measures Higgs width

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.

Physics Briefing |

ATLAS and Seal Storage Technology collaborate on new archival storage

The ATLAS Collaboration has partnered with Seal Storage Technology in a pilot project to explore their decentralised cloud storage platform as an efficient and cost-effective option for archival data storage

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ATLAS celebrates 30 years of collaboration

The ATLAS Collaboration celebrated its 30th anniversary on 1 October 2022.

News |

ATLAS Live talk: Searching for new, long-lived particles at the LHC with Dr. Hideyuki Oide

On 6 October at 2pm CET, Dr. Hideyuki Oide will give a live public talk on the ATLAS Youtube Channel on the LHC's search for new, long-lived particles.

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Using the Higgs boson to search for dark photons

The ATLAS Collaboration has been looking for signs of dark photons in data collected by the experiment during LHC Run 2 (2015-2018). Their newest search targets, for the first time in ATLAS, the production of a Higgs boson in association with a Z boson, with subsequent decay of the Higgs into a photon and a dark photon.

Physics Briefing |

ATLAS Highlights from ICHEP 2022

At ICHEP 2022, the ATLAS Collaboration presented the results of 30 new studies, spanning from Higgs boson and Standard Model measurements to searches for new phenomena.

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ATLAS observes potential four-charm tetraquark

In a new analysis presented at the ICHEP 2022 conference, ATLAS physicists found evidence of a four-charm-quark excess. Like the LHCb Collaboration, ATLAS sees both the X(6900) particle and a broad structure at threshold.

Physics Briefing |

ATLAS measures quantum interference when protons bounce off each other

In a new result presented at ICHEP 2022, ATLAS physicists set out to measure proton scattering at microradian angles and study this quantum interference.

Physics Briefing |

ATLAS measures joint polarisation of W and Z bosons

In a new result presented at the ICHEP 2022 conference, ATLAS physicists have been able to observe events with both a W and Z boson simultaneously polarised longitudinally for the very first time.

Physics Briefing |

Summary of new ATLAS results from ICHEP 2022

The 2022 International Conference on High Energy Physics (ICHEP) kicks off this week in Bologna, Italy. The ATLAS Collaboration will be unveiling a wide range of new results, exploring the full potential of the dataset collected during LHC Run 2 (2015-2018).

News |

ATLAS Experiment records “first physics” at new high-energy frontier

“We have proton collisions in the ATLAS experiment.” At 16.47 CEST, the Large Hadron Collider (LHC) officially kicked off its third period of operation (Run 3). The LHC is colliding proton beams at a world-record-breaking energy of 13.6 tera electron volts (TeV). The higher beam energy and intensity of Run 3 will allow the ATLAS experiment to push the very limits of its physics research.

Press Statement |

LHC Run 3 starts

The Large Hadron Collider is ready to once again start delivering proton collisions to experiments, this time at an unprecedented energy of 13.6 TeV, marking the start of the accelerator’s third run of data taking for physics.

Press Statement |

ATLAS explores the self-interaction of the Higgs boson

In the most recent effort to constrain the Higgs self-coupling constant, ATLAS physicists used the full Run 2 dataset (collected during 2015-2018) to perform a combined study on the production of a single Higgs boson and two Higgs bosons. This single-Higgs analysis was featured in a paper released in Nature today, looking back on 10 years of Higgs boson research at the ATLAS Experiment

Physics Briefing |

10 years of Higgs research

The ATLAS Collaboration at CERN has released its most comprehensive overview of the Higgs boson. The new paper, published in the journal Nature, comes exactly ten years after ATLAS announced the discovery of the Higgs boson. In celebration of this anniversary, a special all-day symposium on the Higgs boson is currently underway at CERN.

Press Statement |

ATLAS & CMS Higgs study 2022

The collaborations have used the largest samples of proton–proton collision data recorded so far by the experiments to study the unique particle in unprecedented detail.

News |

ATLAS Pixel detector in Run 3

The ATLAS experiment at the Large Hadron Collider (LHC) is on the eve of a new data harvest with the restart of the LHC for Run 3. The upcoming four-year run will provide a dataset nearly twice the size of what was collected in Run 2 (2015–2018).

Physics Briefing |