A golden era of exploration: ATLAS highlights from EPS-HEP 2019

Eight years of operation. Over 10,000 trillion high-energy proton collisions. One critical new particle discovery. Countless new insights into our universe. The Large Hadron Collider (LHC) has been breaking records since data-taking began in 2010 – and yet, for ATLAS and its fellow LHC experiments, a golden era of exploration is only just beginning.

20th July 2019

New milestone reached in the study of electroweak symmetry breaking

In the Standard Model of particle physics, elementary particles acquire their masses by interacting with the Higgs field. This process is governed by a delicate mechanism: electroweak symmetry breaking (EWSB). Although EWSB was first proposed in 1964, it remains among the least understood phenomena of the Standard Model as a large dataset of high-energy particle collisions is required to probe it.

15th July 2019

Exploring the Higgs boson “discovery channels"

This week, at the European Physical Society Conference on High-Energy Physics (EPS-HEP) in Ghent, Belgium, the ATLAS Collaboration at CERN released new measurements of Higgs boson properties using the full LHC Run 2 dataset. Critically, the new results examine two of the Higgs boson decays that led to the particle’s discovery in 2012: H→ZZ*→4ℓ, where the Higgs boson decays into two Z bosons, in turn decaying into four leptons (electrons or muons); and H → γγ, where the Higgs boson decays directly into two photons.

12th July 2019

Double the Higgs for double the difficulty

A key interaction not yet observed by LHC experiments is the production of “double Higgs”. The Standard Model predicts that the Higgs field can interact with itself to create a Higgs boson pair. The rate with which this happens is critical, as it allows physicists to directly probe the potential energy of the Higgs field, which is responsible for mass of particles. Deviations from the expectation would be a strong hint of new physics.

11th July 2019

ATLAS searches for rare Higgs boson decays into muon pairs

Today, at the European Physical Society Conference on High-Energy Physics (EPS-HEP) in Ghent, Belgium, the ATLAS Collaboration released a new preliminary result searching for Higgs boson decays to a muon and antimuon pair (H → μμ). The new, more sensitive result uses the full Run 2 dataset, analysing almost twice as many Higgs boson events as the previous ATLAS result.

11th July 2019

ATLAS finds evidence of charge asymmetry in top-quark pairs

Among the most intriguing particles studied by the ATLAS collaboration is the top quark. As the heaviest known fundamental particle, it plays a unique role in the Standard Model of particle physics and – perhaps – in yet unseen physics beyond the Standard Model. A new ATLAS result, presented today at the European Physical Society Conference on High-Energy Physics (EPS-HEP) in Ghent, Belgium, examines the full Run 2 dataset to find evidence of charge asymmetry in top-quark pair events, with a significance of four standard deviations.

11th July 2019

Summary of new ATLAS results for EPS-HEP 2019

ATLAS physicists are in Ghent, Belgium, this week for the European Physical Society Conference on High-Energy Physics (EPS-HEP) 2019. Since its establishment in 1971, the EPS-HEP conference has brought together the high-energy particle physics community every two years to discuss the latest results in field. This year, several hundred physicists from around the world are expected to attend.

11th July 2019

ATLAS highlights from EPS-HEP 2017

The ATLAS Collaboration has presented important new results at the European Physical Society conference on High Energy Physics (EPS-HEP) in Venice (Italy), including the latest analyses of 13 TeV Run 2 data from the Large Hadron Collider (LHC).

12th July 2017

Probing physics beyond the Standard Model with heavy vector bosons

Although the discovery of the Higgs boson by the ATLAS and CMS Collaborations in 2012 completed the Standard Model, many mysteries remain unexplained. For instance, why is the mass of the Higgs boson so much lighter than one would expect and why is gravity so weak?

8th July 2017

New rare pairs of heavy friends in ATLAS

Observing rare productions of heavy elementary particles can provide fresh insight into the Standard Model of particle physics. In a new result, the ATLAS Experiment presents strong evidence for the production of a single top-quark in association with a Z boson.

7th July 2017

Why should there be only one? Searching for additional Higgs Bosons beyond the Standard Model

Since the discovery of the elusive Higgs boson in 2012, researchers have been looking beyond the Standard Model to answer many outstanding questions. An attractive extension to the Standard Model is Supersymmetry (SUSY), which introduces a plethora of new particles, some of which may be candidates for Dark Matter.

6th July 2017

New ATLAS measurement of the Higgs Boson mass

The ATLAS collaboration has released a new preliminary measurement of the Higgs boson mass using 2015 and 2016 LHC data. The number of recorded Higgs boson events has more than tripled since the first measurement of the Higgs boson was released, using 2011/2012 data. An improved precision in the measurement of the Higgs boson mass has been made possible by both the increased collision energy of 13 TeV and improved collision rate.

6th July 2017

ATLAS takes a closer look at the Higgs boson’s couplings to other bosons

Since resuming operation for Run 2, the LHC has been producing about 20,000 Higgs bosons per day in its 13 TeV proton–proton collisions. At the end of 2015, the data collected by the ATLAS and CMS collaborations were already enough to re-observe the Higgs boson at the new collision energy. Now, having recorded more than 36,000 trillion collisions between 2015 and 2016, ATLAS can perform ever more precise measurements of the properties of the Higgs boson

6th July 2017

Chasing the invisible

Cosmological and astrophysical observations based on gravitational interactions indicate that the matter described by the Standard Model of particle physics constitutes only a small fraction of the entire known Universe. These observations infer the existence of Dark Matter, which, if of particle nature, would have to be beyond the Standard Model.

6th July 2017

A first LHC sighting of the Higgs boson in its favourite decay

Until now, the Higgs boson had been observed decaying to photons, tau-leptons, and W and Z bosons. However, these impressive achievements represent only 30% of the Higgs boson decays! The Higgs boson’s favoured decay to a pair of b-quarks, which was predicted to happen around 58% of the time and thus drives the short lifetime of the Higgs boson, had so far remained elusive. Observing this decay would fill in one of the big missing pieces of our knowledge of the Higgs sector. It would confirm that the Higgs mechanism is responsible for the masses of quarks and might also provide hints of new physics beyond our current theories. All in all, it is a vital missing piece of the Higgs boson puzzle!

6th July 2017

Q&A with EPS Outreach Award-Winner Kate Shaw

ATLAS Outreach Co-coordinator Kate Shaw has been awarded the 2015 European Physical Society (EPS) Outreach prize "for her contributions to the International Masterclasses and for her pioneering role in bringing them to countries with no strong tradition in particle physics".

12th August 2015

Physics and performance with 13 TeV proton collisions

After a shutdown of more than two years, Run 2 of the Large Hadron Collider (LHC) has restarted with proton–proton collisions at a centre-of-mass energy of 13 TeV. This new phase will allow the LHC experiments to explore nature and probe the physical laws governing it at scales never reached before.

30th July 2015

ATLAS measurements of the ridge in proton-proton collisions at 13TeV

Previous studies of two-particle angular correlations in proton-proton, proton-lead, and lead-lead collisions at the LHC have provided important insight on the physics of the particle production process. On 24 July, Atlas presented new preliminary measurements of two-particle correlations...

24th July 2015

Of mesons and bosons

ATLAS is ready for detailed physics studies. The experiment used early data collected from the LHC’s Run 2 to calibrate its detectors. Measurements of the production and leptonic decay of certain particle resonances have shown that the detectors and software are working as expected.

24th July 2015

Early Run 2 results test event generator energy extrapolation

On 23 July 2015, ATLAS presented its first measurements of soft strong interaction processes using charged particles produced in proton–proton collisions at 13 TeV centre-of-mass energy delivered by the Large Hadron Collider at CERN. These measurements were performed with a dataset collected beginning of June under special low-luminosity conditions.

22nd July 2015

First Run 2 results to be presented at EPS

The first results using the record-breaking Run 2 data will be presented at the European Physical Society conference on High Energy Physics (EPS-HEP) in Vienna, 22-29 July. It will be an exciting opportunity to see how these first few weeks of data-taking have progressed.

20th July 2015

New searches for SUSY

ATLAS today presented new searches for Supersymmetry, a theory that could explain the large amount of dark matter in the universe.

20th July 2013

New results on the properties of the top quark

At the EPS HEP conference today, ATLAS released a new precise measurement of the top quark mass using events where both top quarks decay via W bosons to electrons or muons. ATLAS also presented limits on the possibility of the top quark decaying to channels not foreseen in the Standard Model. A comparison of the behaviour of top quarks and anti-top quarks produced at the LHC is in agreement with the prediction of the Standard Model, disfavouring models of new physics that require a large top/anti-top asymmetry.

19th July 2013

New Results for EPS

ATLAS physicists will be presenting new results at the biennial Europhysics conference on High Energy Physics this year. The conference, which will take place 18 to 24 July in Stockholm, Sweden, is organized by the High Energy and Particle Physics Division of the European Physical Society (EPS).

16th July 2013

Everyone Here Is Motivated By Physics

In June 1993, ATLAS and CMS were given the provisional go-ahead to submit technical proposals. Twenty years later, for the discovery of the Higgs boson, the European Physical Society has awarded the High Energy and Particle Physics Prize 2013 to the research teams of the ATLAS and CMS experiments. For their “pioneering and outstanding leadership roles in the making” of the experiments, the prize also goes to ATLAS' Peter Jenni and CMS' Michel Della Negra and Tejinder Virdee. We talked to Peter Jenni, who was spokesperson of the ATLAS collaboration for the first 15 years, on ATLAS' past and future.

17th June 2013

A look back at the EPS

I happened to run into Andrey Korytov after his eagerly awaited CMS Higgs talk. No, CMS had not yet seen the Higgs, and ATLAS could breathe a sigh of relief.

30th July 2011

A view inside the ATLAS Higgs combination

Well it's been a few days since the Higgs presentations at EPS, and I'm just recovering from the lack of sleep. It's ironic that I have a newborn daughter, and my sleep deprivation is due to work.

28th July 2011

Arrival at EPS

When I was invited to give a talk on behalf of ATLAS at this summer’s European Physical Society High Energy Physics conference (EPS), I wasn’t really sure what to expect. Most conferences I have been to are relatively intimate affairs where you have long discussions after every talk and then everybody trots down to the pub together to discuss the day’s results. EPS, though, is one of the largest particle physics conferences in the world. Or at least I reckon it is, having eyeballed the number of participants registered on the website, hailing from all sorts of fields ranging from astrophysics to ultra relativistic ions to our very own LHC proton-proton collider physics.

28th July 2011
28th July 2011

ATLAS results revealed at EPS HEP 2011 conference in Grenoble

Many members of the ATLAS Experiment Collaboration have been at the European Physical Society's HEP 2011 conference in Grenoble, France, this week, revealing the results of 35 new and exciting physics analyses for the very first time.

27th July 2011