4 November 2021, Geneva. The ATLAS Experiment at CERN welcomes a brand-new detector: the Muon New Small Wheel system. Its successful installation follows nearly a decade of design and construction, and marks a major milestone in ATLAS’ high-luminosity era.

Following several years of development, ATLAS Collaboration has launched a new "multithreaded" release of its analysis software, Athena.

The ATLAS Collaboration is breathing new life into its LHC Run-2 dataset, recorded from 2015 to 2018. Physicists will be reprocessing the entire dataset – nearly 18 PB of collision data – using an updated version of the ATLAS offline analysis software (Athena). Not only will this improve ATLAS physics measurements and searches, it will also position the Collaboration well for the upcoming challenges of Run 3 and beyond.

ATLAS physicists Florencia Daneri and Waleed Ahmed share the latest news from the Charge-Higgs@LHC workshop, which took place online August 30-31, 2021.

On 23 September 2021 at 8pm CEST, Dr. Maria Moreno Llácer will give a live public talk on the ATLAS Youtube Channel on the top quark. She will explain what makes this quark such a unique particle and describe the role it plays in the search for new physics.

Finding the differences between these types of matter – while extremely challenging – could reveal well-hidden effects that hint at the existence of new particles and interactions. In a new result presented at the TOP 2021 conference, the ATLAS Collaboration probed the heaviest-known elementary particle, the top quark, in search of these effects.

ATLAS’ vibrant physics programme was on full display at EPS-HEP 2021, with members presenting 26 new physics analyses among other key recent results. These were shown in 63 presentations and 45 posters over the five days.

In a new study, the ATLAS Collaboration looked for Z bosons decaying into an electron and an anti-muon, or into a muon and a positron.

The ATLAS Collaboration releases new measurements of the Higgs-boson decay to tau leptons. The result provides new insight into the “Yukawa coupling”, a key interaction of the Higgs boson.

One of the long-term goals of the LHC is to measure the Higgs-boson self-coupling, which in turn can give us clues about the formation of the early Universe. This self-coupling can only be measured directly by studying the production of pairs of Higgs bosons (HH).

The ATLAS Collaboration has released a new result searching for pairs of Higgs bosons (HH) produced by new particles. The Higgs bosons would then each decay into pairs of bottom (b) quarks – known as the '4b decay channel'.

The ATLAS Collaboration announces the first observation of “WWW production”: the simultaneous creation of three massive W bosons in high-energy LHC collisions.

The European Physical Society Conference on High Energy Physics (EPS-HEP 2021) kicks off today. Explore the ATLAS results that will be presented.

Twenty-five years on from the discovery of the top quark, ATLAS physicist Richard Hawkings discusses the history of the particle's discovery, its place in the Standard Model and what it has still yet to tell us.

What can particles of light – photons – tell us about the inner workings of the Standard Model? A new paper from the ATLAS Collaboration measures pairs of photons to improve the understanding of a fundamental force of Nature – the strong force – and thus scrutinise the theoretical models that underpin high-energy physics research.

In celebration of the lowering of the first New Small Wheel detector, CERN is hosting a 360° live event from the ATLAS cavern! Tune in on Thursday 15 July at 5pm CEST.

A new result from the ATLAS Collaboration studies the interactions of photons – particles of light – with lead nuclei at the Large Hadron Collider (LHC). Using new data collection techniques, physicists revealed an unexpected similarity to the experimental signatures of the quark–gluon plasma.

On 1 July 2021, Dr. Hongtao Yang will be giving a live public talk, sharing the story of the Higgs boson's discovery by the ATLAS and CMS experiments. He will explain what ATLAS physicists have learned about this fascinating particle so far, and describe the next steps in its exploration.

The ATLAS Collaboration celebrates the creativity, wealth and scientific impact enshrined in its 1000 papers using LHC collision data. This work – together with that carried out by its sister experiments at the LHC – represents a diversified physics programme that is unprecedented and unequalled in physics research to date.

The ATLAS Collaboration has released three new searches for "higgsinos" - the super-partner of the Higgs boson.

A new search from the ATLAS Collaboration, released this week at the Large Hadron Collider Physics conference (LHCP 2021), sets limits on the mass of the W’ boson.

In a new result presented by the ATLAS Collaboration, physicists have measured – for the first time – the full polarisation vectors for both top quarks and antiquarks.

At the LHCP2021 conference, the ATLAS Collaboration presents a new direct search for the decay of the Higgs boson to charm quarks. Observing this decay would give physicists new insight into the Higgs boson’s relationship with the second generation of matter particles.

The ninth annual conference on Large Hadron Collider physics (LHCP 2021) begins today in video-conference rooms around the world.

Soon after the Big Bang, the Universe was too hot for normal matter to exist. Instead, it was made up of an extremely hot liquid of quarks and gluons: the quark-gluon plasma (QGP). In this live talk, Dr. Anne Marie Sickles explains how physicists at the ATLAS experiment are studying the QGP and what they've have learned.