The Chinese Academy of Sciences (CAS) has awarded members of the ATLAS computing community first prize for their novel use of supercomputer infrastructure. The award was presented to Eric Christian Lançon (ATLAS, IRFU CEA-Saclay laboratory), Andrej Filipcic (ATLAS, Jozef Stefan Institute, Ljubljana), Shan Jin (ATLAS, IHEP, Chinese Academy of Sciences), Gang Chen (IHEP, Chinese Academy of Sciences), Weidong Li (ATLAS, IHEP, Chinese Academy of Sciences), Wenjing Wu (ATLAS, IHEP, Chinese Academy of Sciences), Xiaofei Yan (ATLAS, IHEP, Chinese Academy of Sciences) and Haili Xiao (SCCAS, Chinese Academy of Sciences).

When it comes to large-scale computing, there are two schools of thought: you can take the distributed computing route carried out by the Worldwide LHC Computing Grid (WLCG), where tasks are shared across a vast network of computers around the world. Or there’s High Performance Computing (HPC), where hundreds of thousands of CPUs are joined together to act as a single, massive supercomputer. While these supercomputers may be extremely powerful, they are not always used to their fullest capacity. As they are built around the largest possible job they have to handle, they often have low ‘occupancy’.

"The idea was simple: we need CPUs to run simulations of the proton-proton collision events in our detector, and supercomputers have spare CPUs," explains Eric Christian Lançon, head of the ATLAS software and computing project. "In exchange, we can teach these systems how to process massive amounts of data. There was a common interest to share knowledge, building a bridge between the two worlds of computing."

The ATLAS computing team sought to use China’s unique, interconnected network of supercomputers to run ATLAS jobs. Traditionally, HPC sites are closed environments, not connected to the outside world. If you want to run a job, you have to login to the site – an impractical chore that has, up until now, made connecting supercomputers to the WLCG infrastructure impossible. The Chinese Academy of Sciences, however, has developed a unique, grid-like network of 14 Supercomputers. "This is the only network of its kind in the world," says Eric. "A user can submit a job to the HPC centre and the software selects and distributes it to the best available HPC."

"There was a common interest to share knowledge, building a bridge between the two worlds of computing." says Eric Lançon.

At a small ceremony in CERN's Building 40, three young ATLAS students celebrated the start of their postgraduate studies at CERN. As the recipients of the 2015 ATLAS PhD Grant, Ruth Jacobs (Germany), Artem Basalaev (Russia) and Nedaa B I Asbah (Palestine) have received two years of funding for their studies, spending one year at CERN and another back at their home institute.

Now in its third year, the ATLAS PhD Grant awards talented and motivated doctoral students in the ATLAS experiment. This year, all three of the grant recipients are return-visitors to the ATLAS experiment, having first arrived at CERN during their university studies. "I'm excited to be back," says Ruth Jacobs, who is doing her PhD with the University of Bonn (Germany). "I first came as a summer student while working on my Master's thesis, and am looking forward to starting my studies here in April."

One of the great advantages of the ATLAS PhD Grant is its focus on encouraging student's stay at CERN. "The Grant is an excellent opportunity," comments Artem Basalaev, who is doing his PhD with the Petersburg Nuclear Physics Institute (Russia). "Without this support, I would not have been able to spend a full year based at CERN; I would have only had short visits. When based at CERN, communication is easier: you can go to Building 40, have a coffee, pass by some experts and just ask their advice. That's not possible when you are working remotely from your institute."

Nedaa B I Asbah is also looking forward to being based at CERN while she works on her PhD with DESY /Humboldt University Berlin (Germany). "I found out about the Grant initiative from my supervisor while taking part in the CERN Summer Student programme in 2013," says Nedaa B I Asbah. "I began my first year at CERN this month, working in the ATLAS' ttH (top quark pair and Higgs) group."

The ATLAS PhD Grant was established by former ATLAS spokespersons Peter Jenni and Fabiola Gianotti, who created the fund with Fundamental Physics Prize award money they received in 2013. Applications for this year's Grant are now open.

To sustain the programme over the coming years, the fund is also open to anyone interested in contributing. Visit the CERN & Society website to find out more.

The winners were selected by the ATLAS Thesis Awards Committee for their outstanding contributions to the collaboration in the context of a PhD thesis. A total of 33 nominations were received, all of a very high standard and encompassing major achievements in all areas of ATLAS results and activities.

During the ceremony, the winners gave presentations about their thesis work in front of members of the ATLAS collaboration, including ATLAS Spokesperson Dave Charlton: "We were delighted to hear about their achievements as students on ATLAS," says Charlton, who went on to describe the event as "one of the best parts of my week". He shook hands with the winners and – together with Thesis Committee Chair, Anna Di Ciaccio, and ATLAS Collaboration Board Chair, Katsuo Tokushuku – presented them all with certificates and an engraved glass model of the ATLAS detector.

"It's nice to have recognition for all the hard work," comments Javier Montejo Berlingen, who did his graduate studies with the Institute for High Energy Physics (IFAE) in Barcelona (Spain). "It's something that you basically don't notice while you're doing the PhD but this award has been an opportunity to look back and see how much has been done over all those years. I was part of a nice, small analysis group during my PhD; we were a small family were you could learn a lot. Those people are now really good friends." Javier is continuing his career with ATLAS, doing his post-graduate work with the Trigger and Supersymmetry (SUSY) group as a CERN fellow.

Steven Schramm, who did his PhD with the University of Toronto (Canada), took part in the search for Dark Matter, as part of the exotics group, while also working with the Jet Etmiss group. "It was always very busy – that's life at ATLAS," says Steven. "But it was a very good type of busy and I've had a lot of fun. There's really a sense of community, everyone working together to try to make things as good as possible, trying to deliver an amazing product." Steven is now with the University of Geneva (Switzerland) and, since October 2015, has been the ATLAS Jet Trigger convener.

Winners Ruth Pöttgen and Nils Ruthmann both came to CERN as summer students in 2009. "It was funny as Nils and I were actually studying in the same university, but hadn't known each other very well until we came to ATLAS as students," says Ruth Pöttgen. "During that summer, I worked on the ATLAS pixel detector doing hardware work, installing and changing little devices. It was really cool and it kind of infected me. I always wanted to go back." A few years later, after finishing her diploma, Ruth returned to CERN in 2011 with a Wolfgang-Gentner Scholarship, and affiliated with Johannes Gutenberg University, Mainz (Germany). For her PhD, Ruth carried out a search for Dark Matter in mono-jet events while also working in the ATLAS Central Trigger group. 

Ruth is now doing her post-doctoral studies with Stockholm University (Sweden): "Over the past year I have been focusing on the leptoquark search," she continues. "It has been quite exciting to look at the first 13 TeV data coming out of ATLAS."

"I did most of my PhD work within the ATLAS Higgs group; that's one of the biggest physics groups in ATLAS," says Nils Ruthmann, who did his PhD with the University of Freiburg (Germany). "When I started in 2011, the search for the Higgs was already ongoing in the big channels. Whereas I joined the effort to look for the Higgs decaying into two tau (ττ) leptons, which came a little later as it is a super complex analysis that needs a bit more data. For me, the timing was perfect. From the time I started my analysis to my thesis defence in 2014, I was able to cover the progress to the discovery in the ττ channel."

Now as post-graduate based at CERN, Nils has changed focus to a new area of investigation: SUSY. "With the increase of energy during Run 2, searches for new physics are very important," continues Nils. "A lot of man power is moving from Higgs to SUSY and it should be an interesting time."

Each year the ATLAS Thesis Awards Committee puts forward nominations to the Springer Thesis series and, this year, both Steven Schramm's thesis and Ruth Pöttgen's thesis have been forwarded as the collaboration's nominations.

Women play key roles in the ATLAS Experiment: from young physicists at the start of their careers to analysis group leaders and spokespersons of the collaboration. Celebrate International Women’s Day by meeting a few of these inspiring ATLAS researchers. 

“As an experimental physicist, I am interested in testing new theories that describe how the Universe works,” says Reina Coromoto Camacho Toro, a post-graduate researcher with the University of Chicago. After completing her Bachelor’s and Master’s degrees in her home country of Venezuela, Reina moved to Clermont Ferrand in France to do her PhD in particle physics with ATLAS. “It’s my career now, but when I first started my studies I certainly didn’t know where they could lead. I just knew I was studying something I liked. There are many misconceptions about our work as physicists. Physics relates to everyday events but it still remains foreign to most people and this needs to change."

Reina is now based at CERN full time, looking for evidence of physics beyond the Standard Model. “I am studying interactions that emit two bosons with really high transverse momentum, looking for evidence of new particles,” says Reina. “I am also involved in the upgrade of the Level-1 Calorimeter Trigger, working on the development of a new system called the Global Feature Extraction (gFEX) which will be operational for Run 3 of the LHC.”

“I was always interested in physics as a kid. It had all the interesting parts from chemistry, but none of the test-tube cleaning!” says Isabel Trigger, who works in the ATLAS TRIUMF group. “During my first year as an undergrad I applied for a summer project at Université de Montréal that ended up taking me to CERN. I fell in love with the Lab and, as a result, chose to do my PhD at CERN’s OPAL experiment, looking for the Higgs boson and Supersymmetry.”

Today Isabel is coordinating preparations for the ATLAS small Thin Gap Chamber (sTGC) wedge assembly. “Canada, together with several other countries, is making these detectors for the new small wheel upgrade,” says Isabel. “I spent the last couple of years in Canada setting up a machine to spray a graphite coating onto cathode planes so that we could build them up into detector layers. Now I am based in Geneva, preparing for when the sTGC detectors arrive at CERN and we have to turn them into wedges ready for installation.”

As a particle physicist, Nansi Andari’s studies have taken her around the world. After completing her university studies in her home country of Lebanon, Nansi moved to France to do a second Master’s degree and her PhD. She is now a post-doctoral researcher with the Northern Illinois University (US).

“I’ve always enjoyed physics as it has so many real-world applications; it gives you exciting opportunities to think about the big questions of the Universe,” says Nansi. “As part of the ATLAS collaboration, I analyse data to look for new particles and perform precision measurements of the Standard Model. For my PhD, I looked for the Higgs boson decaying into two photons and was lucky enough to have the discovery in my thesis.”

ProfessorUsha Mallik, with the University of Iowa (US), leads a team of ATLAS researchers. In addition to their involvement in the Liquid Argon detector operation, her team is searching for evidence of the Higgs decaying into pairs of b-quarks: “Every heavy thing and its brother can decay via the b-quark, so it is quite a challenging channel,” explains Usha. “We’re looking forward to getting more data from this year’s run, and hope for a clearer signal by the end of this year. In parallel, we are also searching for ‘beyond the Standard Model’ particles that decay via a Higgs boson into b-quarks and a vector boson.”

Usha is also involved in the Phase II upgrade of the ATLAS detector (scheduled for 2023), conducting performance studies for a high granularity timing detector. She is a strong advocate of improving access to science education, in particular to Pakistan and India (where she was born).

Not every particle physicist dreams about being one as a kid: “It wasn’t until I went to university that I learned about large high-energy physics experiments,” says Nishu. “But the more I learned, the more curious I became about the fundamental constituents of matter and their interactions that govern Nature. So I went on to study particle physics at Panjab University in India, completing my PhD at the CMS experiment. Now, for my post-doctoral studies, I am with the ATLAS experiment doing my work with Tsinghua University in China, though I am mostly based here at CERN.”
   
Nishu is searching for elusive physics beyond the Standard Model. “Many extensions to the Standard Model predict the existence of new massive particles that couple to quarks or gluons,” says Nishu. “If produced by LHC proton-proton collisions, these new particles could decay into quarks or gluons, creating a signal we can detect. I am mainly focusing on the heavy flavour quarks that further increase the signal sensitivity.”

Catrin Bernius first came to CERN in 2004 as a young summer student from Germany. So inspired by the experience, she chose to do her PhD with University College London (UCL), looking for Higgs decays to b-quarks in the ATLAS experiment.

She is now an active member of the ATLAS trigger group, as a research associate at New York University. “I’m currently coordinating the operation of ATLAS trigger system, the system deciding which events are recorded and which are discarded in real time,” says Catrin. “The work is diverse and rewarding, though it can be quite challenging at times. Fortunately, I work with a great team of dedicated experts, which always makes heading into the office a lot of fun.” Additionally, she is analysing recorded data to search for new physics in the compressed, electroweak Supersymmetry sector.

As deputy spokesperson of the ATLAS collaboration, Dr.Beate Heinemann is involved in overseeing all aspects of the ATLAS experiment, from detector and computing operations to physics analysis. “As particle physicists, we look to increase the overall knowledge of humanity,” says Beate. “This search can lead to revolutionary developments, both for society and technology. For example, quantum mechanics led to the development of the transistor which in turn led to the development of computers.”

Beate is a Professor at the University of California, Berkeley, and Senior Physicist at the Lawrence Berkeley National Laboratory. “I am part of a great team in a fantastic working environment,” continues Beate. “My collaborators on the ATLAS experiment have a broad range of expertise, ranging from hardware development to physics analyses. It’s hard not to be inspired!”

This year’s 50^th anniversary edition of the “Moriond Electroweak and Unified Theories” conference at La Thuile in Italy highlighted the recently announced observation of gravitational waves from a binary black hole coalescence by the LIGO/Virgo collaboration, as well as the presentation and discussion of the first results from the LHC full-year 2015 data samples (“Run 2”) collected by the LHC experiments at unprecedented 13 TeV proton-proton collision energy. The ATLAS and CMS collaborations each showed numerous new Run 2 results at the conference (see links below).

ATLAS also presented several important Run 1 measurements in the domain of rare and precision physics. Among these are the total and differential cross-sections of “di-boson” W+W and W+Z production. Both are important tests of the Standard Model showing that accurate higher-order theoretical calculations are needed to describe the experimental results. ATLAS also showed new searches for the so-called "vector-boson scattering", which describes a specific process of four-boson interactions that would infinitely rise in cross-section with the proton-proton collision energy were there not the Higgs boson to moderate this rise. Such processes are thus intimately related to the electroweak symmetry breaking sector of the Standard Model.

ATLAS also presented their full Run 1 result of a search for the extremely rare decay of a B_s meson to a muon pair (a few 10^–9 decay probability). That decay was observed by CMS and LHCb in 2014 from a combination of their datasets with a measured branching fraction in agreement with the expectation. The ATLAS analysis resulted in a signal that is smaller than expected but still compatible with the Standard Model at the two standard deviation level.

Among the 13 TeV Run 2 results, ATLAS presented Standard Model and Top physics measurements of single and double W/Z boson production, top-antitop production as well as so-called “single top” production which is an electroweak interaction process. ATLAS also presented a preliminary 13 TeV measurement of top-antitop production associated with a W or Z boson. These processes have low cross-sections, but because of their topology represent important backgrounds to the search for Higgs boson production with a top-antitop pair. The measurements are found to be in agreement with the Standard Model predictions within the currently large statistical uncertainties. First measurements of inclusive Higgs boson production in the cleanest four-lepton and two-photon decay channels resulted in smaller signals than expected, which are however fully compatible with the Standard Model as the data sample is still modest.

ATLAS presented a large set of searches for new physics at the conference. Such searches are the experiment’s primary focus for the early Run 2 phase due to the increased sensitivity to production of putative new high-mass states at the 13 TeV collision energy. The analyses covered searches for additional charged or neutral Higgs boson production, supersymmetry or exotic heavy quark partners, and the production of heavy resonances decaying to jets, bottom or top quarks, W, Z or Higgs bosons, leptons or photons, and combinations of these. Also searches for new heavy long-lived particles that travel through the detector with significantly less than the speed of light were presented. None of these searches showed a significant deviation from the Standard Model expectations.

The search for a heavy scalar (spin-0) resonance decaying to two photons presented by ATLAS in December 2015 exhibited an excess of events at around 750 GeV in the diphoton mass spectrum. At the Moriond conference, a preliminary update of this analysis was shown that included additional cross-checks and a search for a spin-2 particle (inspired by models with strong gravity), which features less stringent transverse momentum requirements and a different method for estimating the background. This and the original spin-0 analysis see a similar excess of events at 750 GeV with largely overlapping datasets. The global significances of this excess, taking into account the increased probability of statistical fluctuation of data in broad search regions, are 2.0 and 1.8 standard deviations for the scalar and spin-2 analysis, respectively. ATLAS has also reanalysed their 8 TeV dataset from Run 1 in view of this excess. Assuming the putative 750 GeV resonance to be produced through the scattering of gluons in the protons, the compatibility of the 13 TeV and 8 TeV results is 1.2 (2.7) standard deviations for the spin-0 (spin-2) analysis. ATLAS has also sought a resonant signal in the Z+photon mass spectrum in the 13 TeV data, for which no evidence was found. The upcoming restart of the LHC is expected to clarify the current uncertainty in the interpretation of these findings.

Many of the results described here are summarized at http://atlas.cern/updates/physics-briefing.

Links:

• All results from the ATLAS Collaboration: https://twiki.cern.ch/twiki/bin/view/AtlasPublic/WebHome 
• Collections of recent ATLAS Run 2 results: https://twiki.cern.ch/twiki/bin/view/AtlasPublic/December2015-13TeV, https://twiki.cern.ch/twiki/bin/view/AtlasPublic/Winter2016-13TeV 
• All results from the CMS Collaboration are available at this link: http://cms-results.web.cern.ch/cms-results/public-results/publications 

This morning the Large Hadron Collider (LHC) circulated the first proton-proton beams of 2016 around its 27 kilometre circumference. The beams were met with great enthusiasm in the ATLAS Control Centre as they passed through the ATLAS experiment.

These beams mark the start of an exciting new period for ATLAS and other CERN experiments. Having seen tantalising but still inconclusive signals in 2015, ATLAS physicists around the world are eagerly awaiting new data to analyse.

The start of a new run also means the conclusion of a maintenance period, known as the Year-End-Technical-Stop (YETS). This 3 month-long upkeep is vital for the health and well-being of the detectors, ensuring that ATLAS can function impeccably for the 9 straight months of operation that follow.

“This is a normal period of maintenance that happens yearly,” says Michel Raymond, ATLAS Deputy Technical Coordinator. “At ATLAS we use this time to repair and consolidate the detectors first, but also all the infrastructure around that allows us to run the detector.”

But before their work can begin, there is a lot preparation needed. Although located in an enormous 52,500 m³ cavern, the ATLAS experiment fills that space nearly to the brink. Whatever room is left over is devoted to the cabling and cooling infrastructure that keeps the experiment running. “You cannot just go in and start working on a detector element,” says Raymond. “We first need to move the shielding and cabling to get the experiment into a configuration where the requested detector is accessible.”

Moving these elements is called “opening” the detector and can take at least 3 weeks. The ATLAS teams have to go slowly and carefully, as they are moving fragile equipment that can weigh anywhere between 100 to 1000 tonnes.

Once the detector elements are accessible, the teams have only a few weeks to get to work before they need to start closing the detector back up. “Every hour in the cavern is precious,” says Raymond. “We prioritise in advance what operations are the most important, and which can wait for next maintenance period.”

During this YETS period, the main priority was the repair of ATLAS’ end-cap magnet bellows. These bellows protect the integrity of the vacuum surrounding ATLAS cooling elements, and are essential for keeping the magnet system cool. They were damaged during a previous maintenance period though continued to work adequately throughout 2015. The damage was successfully repaired during this recent shutdown.

“After that, we took action on the detector elements, repairing wear-and-tear damage,” says Raymond. “There was a lot of work needed on the muon chambers and the Tile Calorimeters, replacing faulty electronic elements; and a number of gas connections had to be replaced on both sides of the experiment, to avoid leaks.”

With the work now complete and beams running through the LHC, most of the ATLAS Collaboration has turned their focus to the data. However Michel and his colleagues continue to look forward to their next trip underground.  “We’re always planning ahead, thinking about the next shutdown and the ones after that,” concludes Raymond. 

Spring is now in full bloom at the ATLAS experiment which recorded the year’s first collisions for physics on Monday, 9 May. Event displays from these collisions were immediately streaming on the ATLAS live website, with some shared across social media platforms.

But what do these beautiful, complex images represent? Known as “event displays”, these snapshots are high-tech visualisations of information recorded by the ATLAS experiment. But their history and development are as complex as the particles they display.

“Particle physicists study a field that is, by its very nature, invisible to the naked eye,” says Riccardo-Maria Bianchi, who works on ATLAS visualisation software. “That can make the task of visualising particle interactions very challenging.”

In the 20th century, physicists developed particle detectors such as cloud chambers and bubble chambers that turned invisible interactions into visible tracks. With the help of high-speed cameras, these tracks were captured on film to create the world’s first event displays.

However, as experiments have grown in size and complexity, a simple point-and-shoot approach will no longer do. When experiments go digital, particle collisions are recorded as electronic data and event displays evolve to become computer-generated visual representations of that data.

The ATLAS collaboration use two types of visualisation software: VP1 and Atlantis. Both were specifically developed for the ATLAS experiment to analyse data directly and convert them into graphical objects. Each software has a specific area of expertise.

VP1, or Virtual Point 1, provides interactive 3D event displays. The software uses detailed geometry to display a particle’s path through the ATLAS experiment. “When we run our experiment (or when we design a new piece of it) we need to check the performance of every detector layer to make sure they respond as we expect,” says Riccardo-Maria Bianchi. “Interactive data visualization tools like VP1 let us follow these particles through the entire experiment, starting from their birth at the interaction point.” VP1 software is also used for physics analyses, for example allowing users to view different subsystems and use tools to mask channels.

Meanwhile, Atlantis creates two-dimensional event displays that are prominently showcased in the ATLAS control room. “It’s the heartbeat of ATLAS,” says Paul Laycock, ATLAS Data Preparation Coordinator. “We monitor each and every subsystem individually in the control room, but Atlantis brings the information together in a way that’s immediately intuitive. At a glance we can see that everything is OK.” The events seen in the control room are also quickly transferred to the ATLAS Live website, providing a real-time look at data coming from the experiment to the public.

“We analyse billions of events using sophisticated statistical techniques; we can’t afford to look at each event individually,” continues Paul Laycock. “However a picture is worth a thousand words, and event displays help us describe and understand analyses using our physics intuition.”

So the next time you see one of these stunning event displays on your twitter feed or in a scientific paper, take a moment to appreciate the decades of work that went into its development.

Discover more ATLAS event displays here.

From techno beats to classical melodies, from jazz swinging to pop and rock riffs – the ATLAS experiment can play them all. Thanks to Quantizer, a platform that translates ATLAS events into notes and rhythms, one of the most complex scientific instruments in the world will not only search for new physics, but also generate music.

Quantizer was conceived by Juliana Cherston, a Master’s student in the Responsive Environments Group at the MIT Media Lab, and designed in partnership with ATLAS Doctoral student Ewan Hill from the University of Victoria. They have just released Quantizer on the web, providing real-time audio samples produced with the latest data.

“I did my undergraduate degree in physics and I spent a couple of summers at CERN working for the ATLAS experiment,” says Juliana Cherston. “I was really inspired by the place, so I started my Master’s studies already knowing what I wanted to work on: more artistic and creative ways of using high-energy physics data.”

Less than a year later, her project became a reality. Quantizer challenges artists and composers to explore the thin border between science and art. At the same time, it is a powerful tool for outreach and education, since its music embodies fundamental physics research in a more intuitive and appealing way. But how does it work?

First, Quantizer takes the data released through the ATLAS Live website and applies a noise filter. It then clusters the data geometrically, scales it and shifts it – to ensure that the output is in the audible frequency range – and then maps the data as notes.

Considering its origin, it is not surprising that one can recognise physics phenomena within the music. “You can hear lower notes more often than higher notes, because less energetic particles are more common than highly energetic ones,” explains Ewan Hill, who supervises the data selection and the first translation steps. “At the same time, Quantizer makes use of the particle spatial distribution, so that you can hear the geometric symmetries of the detector in the music.”

Last July, Quantizer gave its first performance at the Montreux Jazz Festival, as part of the third ThePhysics of Music and the Music of Physics event. A few days before the festival, Quantizer held a workshop with twenty composers who worked with the software, exploring all the possibilities it provides. “The hardest and most intriguing part of the project has been figuring out how to manage the tension between the randomness of data and the structure of music,” says Juliana Cherston. “For this reason, working side by side with composers is extremely important, especially in this starting phase.”

Most recently, the project was presented at the CHI 2016 conference (paper available here). Different elements of the project will be presented at the New Interfaces in Musical Expression conference in July 2016 and at ICHEP in August 2016.

Discover Quantizer for yourself and listen to the wonderful sound of physics!

The Large Hadron Collider Physics (LHCP2016) conference kicked off today in Lund, Sweden. Held annually, the LHCP conference is an opportunity for experimental and theoretical physicists to discuss results from across the high-energy physics community. From Standard Model Physics and Heavy Ion Physics to Supersymmetry and other Beyond Standard Model investigations, the conference unites the disciplines to examine recent progress and consider future developments. 

ATLAS scientists will be presenting the latest analyses of 2015 data at 13 TeV, as well as new analyses of 8 TeV Run 1 data. Many of these results include refined calibration and analysis techniques that have further developed the understanding of the ATLAS data, ensuring that the detector, trigger, computing and analysis run as efficiently as possible. This will prove essential as the experiment moves into the upcoming period of data-taking. 

Results using early 2016 data will also be presented at LHCP2016, with a focus on the performance of the detector. 

“The completion of many analyses of Run 1 and 2015 data for LHCP shows the scope and breadth of the ATLAS physics programme,” said Rob McPherson from the University of Victoria, ATLAS Deputy Spokesperson.  “The stage is now set for 2016, with new results with a much larger data set at the highest LHC energies expected by mid summer.”

One of the greatest challenges faced by the ATLAS experiment is the increasing “pile-up” seen in Run 2 data. “Pile-up” consists of numerous additional proton collisions that do not result in what physicists would consider interesting physics, and can drown out signals of much sought-after heavy particles. As the LHC increased its luminosity in 2016 by squeezing the intersecting bunches by a factor of two, this “pile-up” doubled! But thanks to months of hard work to improve detector performance and incorporate all-important calibration measurements, ATLAS physicists are now able to navigate these challenging new waters. 

Results using early 2016 data will also be presented at LHCP2016, with a focus on the performance of the detector. While this year’s run is still in its infancy, ATLAS is already seeing good agreement between the data taken in 2015 and 2016. The hard work of ATLAS analysis teams has paid off – an excellent sign of things to come!

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ATLAS released Physics Briefings highlighting key new results presented at the LHCP2016 conference. Make sure to check out:

• Stacking the building blocks of the 2016 ATLAS Physics Programme, 13 June 2016
• Weighing in on the top quark mass, 13 June 2016
• A peak inside the proton…, 14 June 2016
• Something went bump in the night, 15 June 2016
• Di-photons in the spotlight, 15 June 2016
• Continuing the search for extra dimensions, 16 June 2016

On Friday 29 July, the ATLAS experiment at CERN released the data from 100 trillion proton-proton collisions to the public. This includes the world’s first open release of 8 TeV data, gathered from the Large Hadron Collider in 2012, making it the most current high-energy physics open data.

The ATLAS Open Data release embraces the spirit of open access established by the CERN Open Data portal. “The ATLAS collaboration exemplifies the culture of open science, with thousands of physicists working around the world to further our understanding of the universe,” says Kate Shaw, ATLAS Outreach Co-coordinator. “Making our data publicly available is a natural development of this open culture.” 

Learn by doing

Unique to the ATLAS Open Data release is its strong emphasis on learning. In parallel with the data release, ATLAS has launched a comprehensive educational platform to guide students and teachers at university level through how to use the data and the corresponding analysis tools. 

“This platform is a key part of the ATLAS Open Data release,” explains Felix Socher, ATLAS physicist with TU Dresden who lead the development of the release. “It bridges the gap between physicists and the public, with extensive documentation to demystify the data analysis process. Users can follow worked examples using the ATLAS open dataset, and then carry out analyses on their own.”

From theory to reality
    
ATLAS has made seven physics analyses available to help users get started with their research. By providing theoretical predictions of certain interactions, these analyses give necessary context to the real ATLAS data. Users can compare real data to theory, carrying out measurements of Standard Model particles, hunting for the Higgs boson and even searching for physics beyond the Standard Model.     

As the Open Data platform grows, users can look forward to new content. “We are planning to release further analyses, additional documentation and, eventually, more data,” says Socher. “We especially want to hear from our community of users. Our next releases will address their feedback.”

Easy access 

The ATLAS Open Data platform also addresses a common problem faced by open data releases: storage space. Without downloading a single file, users will be able to access and analyse ATLAS data. “By removing this technical hurdle, students and teachers will be able to focus on what’s important: understanding the physics processes and making appropriate cuts and selections to lead to a discovery,” says Arturo Sánchez Pineda, ATLAS researcher with University of Naples Federico II and INFN who developed the Open Data platform. “If they then decide to carry out a more complex analysis, all of the necessary software, tools and datasets are available for download on the platform.”

The ATLAS data and tools currently weigh in at just under 11 GB – making them easy to store on personal computers. This flexibility opens new doors for educators in developing countries who may have limited computing resources. Moreover, for those who have little-to-no internet connection, the ATLAS Data and Tools team will be making the entire platform available on USB sticks.*

Get started!

Start your analysis now! Visit the ATLAS Open Data website or the CERN Open Data portal to access the data and tools. 

*Contact atlas.outreach.data.tools@cern.ch to request the full ATLAS Open Data platform on a USB stick.

3 August, 2016. It’s been a good summer for the ATLAS experiment. Thanks to the exceptional performance of the Large Hadron Collider and the continued efficient data-taking of the detector, ATLAS is releasing results with 12 inverse femtobarns of data recorded at 13 TeV in 2016. This is nearly four times larger than the 2015 dataset – and the year is not yet over.

Results using this record-breaking 2016 data will be presented at the International Conference on High Energy Physics (ICHEP) in Chicago, 3-10 August. Held every two years, ICHEP brings together physicists from around the world to share the latest advancements in particle physics, astrophysics, and accelerator science and to discuss plans for major future facilities. 

Preparations for ICHEP have kept everyone at ATLAS on their toes. From detector operations and trigger to computing and analysis, ATLAS teams have worked tirelessly to collect and analyse this new wealth of data. Thanks to their efforts, 50 new conference notes have been prepared especially for ICHEP. 

Along with detailed studies of Standard Model processes and searches for new physics, the ATLAS collaboration is looking forward to shedding new light on the modest “excess” seen in the 2015 data. New studies of the Higgs boson will also be shown, including searches for the famous particle using 2016 data.

These key results will be explored in ATLAS Physics Briefings, to be released throughout the conference. Check the ICHEP2016 tag for the latest updates.

ATLAS will be hosting a series of Facebook Live events for its social media followers. Tune in to hear members of the collaboration discuss the latest ICHEP results.

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.

Dortmund is the first university to use ATLAS Open Data in this way. During the current semester, an 8-hour lab course has been offered to first-year Master’s students. “It has been quite a success,” says Kevin Kröninger, ATLAS member and supervisor of the new lab course at Dortmund. “Students were pretty excited to see it added to the roster, and have been eager to enrol.”

“During the course, students search for new physics signals, which would show up as a resonance over Standard Model top-antitop production,” says Sonja Bartkowski, the main developer of the course. “Using simulated data, they can identify the key variables that discriminate between signal and background. They then apply these selections to real data.”

“Three groups of students have already attended the new lab course,” says Johannes Erdmann, who collaborated with Kevin and Sonja. “Until now, the response has been extremely positive, but we are gathering as much feedback as possible in order to make further improvements.”

Other universities can follow in Dortmund’s footsteps using the ATLAS Open Data platform, which was launched in July 2016 in parallel with the data release. The platform provides all the tools that students need to start their own analysis. Complete analysis packages are freely available; in addition to the data, they include visualisation and analysis software, clear instructions, and worked examples.

The aim of ATLAS Open Data is to give students a realistic idea of what it means to be a physicist. “The datasets have been simplified to allow easier understanding,” says Susan Cheatham, ATLAS member with University of Udine and a developer of the Open Data website. “This allows students to dive straight into the analysis.” In this way, they can have a taste of real-life research.

If you are interested in developing a course to engage your students in particle physics research, visit the ATLAS Open Data website and get started now!

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. 

“There are a lot of excellent, hard-working people in ATLAS, as displayed by the quality and quantity of the nominations we received,” said Stephen Haywood, Chairperson of the selection committee. “As such, the committee had to make many hard choices, as we tried to pick out the ‘outstanding’ from all the excellent work nominated.”

As in previous years, nominations came from across the collaboration, in areas such as technical coordination, detector systems, as well as activity areas including upgrade, combined performance and outreach. The Collaboration Board Chair Advisory Group examined each of the 62 nominations to make their final selections.

The first to receive their awards were Marcello Bindi (University of Göttingen), Laura Jeanty (Berkeley National Lab), Kerstin Lantzsch (University of Bonn), Karolos Potamianos (Berkeley National Lab) and Yosuke Takubo (KEK). They were celebrated for their outstanding contributions to the successful commissioning and operation of the Pixel Detector for the start-up of Run 2.

Dmitri Kharchenko (JINR), Uladzimir Kruchonak (JINR), Konstantin Levterov (JINR) and Enrico Pastori (University of Rome Tor Vergata and INFN) were celebrated for developing new techniques ensuring stable operation of the RPC gas system.

For his contribution to the operations and upgrade of the TileCal Detector Control System, ATLAS awarded Filipe Martins (Laboratory of Instrumentation and Experimental Particle Physics (LIP)).

For their outstanding contributions to ensuring the integrity of the Trigger during Run 2, the ATLAS Experiment presented awards to Ricardo Abreu (University of Oregon), Patrick Czodrowski (CERN), Carlos Barajas (University of Sussex), Joana Machado Miguens (University of Pennsylvania) and Mark Stockton (McGill University).

This year, in addition to awarding specific members of the collaboration, special recognition was also given to ATLAS and CERN groups. The ATLAS Magnet Team, CERN VSC (Vacuum, Surfaces & Coatings) Team, CERN Central Workshop and CERN Detectors Technology Operations Group were celebrated for their outstanding work on the vacuum bellows for the Endcap C Toroid.

For providing prompt data reconstruction at Tier 0, especially during the 2015 run, ATLAS awarded Magda Chelstowska (CERN) and Christian Ohm (Berkeley National Lab).

Attila Krasznahorkay (CERN) was given an award for his outstanding contributions to the development and implementation of the Run 2 analysis model, in particular the development of the xAOD.

And finally, Matthias Danninger (University of British Columbia) and Hideyuki Oide (University of Genoa and INFN) were celebrated for their outstanding contributions to the real-time tracking of the Insertable B-Layer alignment.

Having a precise measurement of the luminosity allows ATLAS physicists to calculate the rate at which the processes they’re interested in are expected.

Citizen scientists are asked to examine ATLAS event displays, looking for “off-centre vertices” where several tracks intersect away from the central collision point. 

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.

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

Now in its fourth year, the Grant gives doctoral students an opportunity to benefit from world-class research, supervision and training within the ATLAS collaboration. The students receive two years of funding for their studies, spending one year at CERN and another back at their home institute. 

On Tuesday 14 February, the 2017 ATLAS PhD Grant recipients were presented with certificates at a small ceremony in CERN's Building 40. It was a chance for Chilufya Mwewa (University of Cape Town), Santiago Paredes Saenz (University of Oxford) and Giulia Ripellino (KTH Royal Institute of Technology) to meet the committee members and share stories with the previous year’s recipients.

The ATLAS PhD Grant was established by former ATLAS spokespersons Fabiola Gianotti and Peter Jenni, who created the fund with Fundamental Physics Prize award money they received in 2013. Hopefully the Grant will be sustained over the coming years with the support of private contributions. Visit the CERN & Society website to find out how you can contribute.

Chilufya Mwewa (University of Cape Town)

Born in Zambia, where she also did her undergraduate studies, Chilufya attended the African School of Physics in 2010. “That was my first exposure to the incredible world of particle physics,” she says. “It was also where I learned about high-energy physics opportunities in African universities.” Chilufya went on to speak about the support she received from her professors, all of whom encouraged her to pursue a career in particle physics. 

“I'm really thankful for the opportunity this grant has given me,” says Chilufya. “I'm now able to work in close collaboration with various ATLAS personnel within the CERN environment, which I really appreciate.“ For her thesis, Chilufya will be carrying out a same-sign WW analysis in the ATLAS Standard Model electroweak subgroup. In addition, she will be working on validation studies for the ATLAS New Small Wheel software.

Santiago Paredes Saenz (University of Oxford)

When looking for funding for his PhD, Santiago found limited opportunities for students from Latin America. “My university suggested that apply for the ATLAS PhD Grant, which has no such nationality restrictions,” says Santiago, who is from Ecuador. “To be honest, I thought it was a long-shot. I was very honoured to be selected!”

Santiago will be carrying out a di-Higgs search within the ATLAS Exotics group for his thesis, and is also working on the jet missing-energy trigger for his qualification task. “It is quite challenging work, but I’m really enjoying it,” he concludes.

Giulia Ripellino (KTH Royal Institute of Technology)

“One of the great advantages of this scheme is the year spent at CERN,” says Giulia. “As I learned during my experience as a Summer Student, there is nothing to compare with the atmosphere of CERN. You can easily meet with people, ask questions and feel more involved in the day-to-day work of the collaboration.”

“I also really appreciate the multinational environment,” she continues. “I am of both Swedish and Italian descent, and it is really great to see people from lots of different countries all working together.” Giulia is carrying out a supersymmetry search for her thesis, having also worked on the alignment of the ATLAS Inner Detector.

Visit the CERN & Society ATLAS PhD Grant webpage for more information.