Searching for signs of the “stop”

In new results presented at the Moriond Electroweak conference, the ATLAS Collaboration has sifted through the full available data sample of the LHC’s 13 TeV proton collisions in search of a specific SUSY particle: the heavy partner to the top quark, called the “top squark” or “stop”

Physics Briefing | 21 Mar 2017

The search for super-particles continues!

Many of the most important unanswered questions in fundamental physics are related to mass. Why do elementary particles, which we have observed and measured at CERN and other laboratories, have the masses they do? And why are they so different, with the mass of the top quark more than three hundred thousand times that of the electron? The presence of dark matter in our universe is inferred because of its mass but, if it is a particle, what is it? While the Standard Model has been a tremendously successful theory in describing the interactions of sub-atomic particles, we must look to even larger masses in search of answers and, potentially, new supersymmetric particles

Physics Briefing | 20 Mar 2017

ATLAS to present new results at Moriond

Every March for the past 50 years, particles physicists have been heading to the mountains. The terminus of this migration? Les Rencontres de Moriond, one of the year’s first major conference for high-energy physics.

News | 19 Mar 2017

New management at the ATLAS Experiment

Karl Jakobs from the University of Freiburg is a familiar face at CERN and in the ATLAS Experiment. He’s been part of the collaboration since the signing of the ATLAS Letter of Intent in 1992, having taken on various coordination roles, and followed the experiment through all its phases. Now, after twenty-five years with the collaboration, Karl is moving into the main office as spokesperson.

News | 03 Mar 2017

Award season at the ATLAS Experiment

From detector development to detailed searches for new physics, ATLAS PhD students publish dozens of outstanding theses every year. Since 2010, a few have been celebrated at the annual ATLAS Thesis Awards.

News | 28 Feb 2017

Meet the talented recipients of the ATLAS PhD Grant

Motivated. Outstanding. Enthusiastic. These are the criteria used when selecting the recipients of the ATLAS PhD Grant. It’s a tough competition.

News | 16 Feb 2017

How strange is the proton?

What precision measurement of the inclusive W+, W− and Z/γ∗ production cross sections can tell us about the true nature of the proton.

Physics Briefing | 25 Jan 2017

Return of the top quark!

For the first time, ATLAS has measured the kinematics of the top quark and of the tt̅ system in 13 TeV events containing two charged leptons, two neutrinos and two jets (called “dilepton” events).

Physics Briefing | 13 Jan 2017

The trouble with terabytes

2016 has been a record-breaking year. The LHC surpassed its design luminosity and produced stable beams a staggering 60% of the time – up from 40% in previous years, and even surpassing the hoped for 50% threshold. While all of the ATLAS experiment rejoiced – eager to analyse the vast outpouring of data from the experiment – its computing experts had their work cut out for them.

News | 14 Dec 2016

Measuring the W boson mass

The ATLAS collaboration is now reporting the first measurement of the W mass using LHC proton-proton collisions data at a centre-of-mass energy at 7 TeV. The ATLAS result matches the best single-experiment measurement of the W mass performed by the CDF collaboration.

Physics Briefing | 13 Dec 2016

Become a Higgs Hunter

HiggsHunters is the first mass-participation citizen science project for the Large Hadron Collider, allowing non-experts to get directly involved in physics analysis. Since its launch in 2014 on the Zooniverse platform, over 30,000 people from 179 countries have participated in the project. Their work has led to the project’s first publication on arXiv.

News | 05 Dec 2016

Is there life after physics?

Am I going to dedicate my entire life to high-energy physics? Am I qualified to work in another field, if I wish to? These are questions we may ask ourselves as we near the end of a contract. On Tuesday 29 November, the four experiments, ATLAS, ALICE, CMS and LHCb, organized a meeting with some of their former physicists who had decided to take the plunge into the business world.

Blog | 02 Dec 2016

What happens when energy goes missing?

Here at ATLAS, we like to consider ourselves pretty decent at tracking down particles. In fact, we do it every day. Just because a proton-proton collision doesn’t produce the next Nobel Prize winning particle doesn’t mean we can ignore it. Teams of physicists are still combing through every single event, rebuilding known particles out of the signals they leave us

Blog | 03 Nov 2016

Counting collisions

Whether searching for signs of new physics, or making precise measurements of known interactions, it is essential to know the total number of proton-proton collisions that the LHC delivers in ATLAS. This parameter, known as “luminosity”, is a vital part of ATLAS analysis.

News | 27 Oct 2016

ATLAS awards outstanding achievement

The 2016 ATLAS Outstanding Achievement Awards ceremony was held at CERN on 20 October. Now in its third year, the awards give recognition to excellent contributions made to the collaboration, with an emphasis on activities carried out in the first year of Run 2.

News | 24 Oct 2016

The many faces of research

Ever since the age of 10, as far as I remember, I have been fascinated by technical and natural sciences, especially physics. I loved building (and repairing) experiments or things. As a result, in high school I happily attended an advanced course in physics and continued my studies at RWTH Aachen University (Germany).

Blog | 17 Oct 2016

Higgs over easy

My colleagues and I are in town to attend the 22nd International Conference on Computing in High Energy and Nuclear Physics (CHEP 2016, for short). I like to think of us as the nerds of the nerds. Computing, networking, software, middleware, bandwidth, and processors are the topics of discussion, and there is indeed much to talk about.

Blog | 12 Oct 2016

Dortmund students work with ATLAS data

The ATLAS Open Data platform is inspiring new ways to teach high-energy physics. Universities can incorporate the data into their curriculum, giving their students hands-on analysis experience and introducing them to the world of research.

News | 29 Sep 2016

An exceptional summer

For many students, summer means sun and beach volleyball. For some, though, it is an opportunity to learn at ATLAS! Thanks to CERN’s Summer Student Programme, every year dozens of university students come to ATLAS to spend their holidays in this unique environment. During these three months they alternate between lectures and work, always supported by their supervisors. This summer, ATLAS hosted 50 students from 31 different countries. Here are some of their stories.

News | 30 Aug 2016

Precision measurements with multi-TeV energy jets

The strong force is one of the four fundamental interactions of Nature. It governs the interactions between quarks and gluons, and is thus responsible for the stability of ordinary matter. In the proton-proton collisions at the Large Hadron Collider, the strong force is seen in the production of collimated sprays of mesons and baryons, known as hadron jets. The ATLAS Collaboration has released the measurement of the inclusive jet production cross sections at the new 13 TeV energy frontier.

Physics Briefing | 23 Aug 2016

ATLAS highlights from ICHEP2016

The International Conference on High Energy Physics (ICHEP) wraps up its 38th edition today in Chicago. For ATLAS, it brings to a close an intense period of analysis. The collaboration presented 64 new sets of results at the conference, ranging from detector performance studies to measurements of Standard Model processes to searches for new physics. All in all, a rather stellar turnout.

News | 10 Aug 2016

ICHEP results presented with style!

For those of you with an affinity for Twitter, you’ll know that the ICHEP press crew have been utilising all of their dark arts to bring you the most interesting results as they’re presented at ICHEP 2016.

Blog | 08 Aug 2016

Hunting for new physics with boosted bosons

One of the most direct ways to search for the unexpected is to look for new particles, often with multi-TeV mass. These heavy particles are featured in beyond the Standard Model theories and could be created at the Large Hadron Collider.

Physics Briefing | 06 Aug 2016

Double the bosons, double the excitement

ATLAS has performed measurements of boson-pair production using data from 13 TeV proton-proton collisions that began in 2015. The cross-section (a measure of the production frequency) of the WW boson pair production was measured and was compared to a previous measurement in 8 TeV collisions.

Physics Briefing | 05 Aug 2016

High-mass di-photon resonances: the first 2016 ATLAS results

One of the highlights of last year’s physics results was the appearance of an excess in the search for a new particle decaying into two photons ("the di-photon channel"). New results in this channel were presented at the ICHEP conference in Chicago on Friday, 5 August.

Physics Briefing | 05 Aug 2016