Highlights from Moriond: ATLAS explores the full Run 2 dataset

This week, particle physicists from around the world gathered in La Thuile, Italy, for the annual Rencontres de Moriond conference on Electroweak Interactions and Unified Theories. It was one of the first major conferences to be held following the recent completion of the Large Hadron Collider’s (LHC) second operation period (Run 2). The ATLAS Collaboration unveiled a wide range of new results, including new analyses using the full Run 2 dataset, as well as some high-profile studies of Higgs, electroweak and heavy-ion physics.

23rd March 2019

All together now: adding more pieces to the Higgs boson puzzle

The Higgs boson was discovered in 2012 by the ATLAS and CMS experiments, but its rich interaction properties (its coupling to other particles) have remained a puzzle. Thanks to an unprecedented amount of Higgs bosons produced at the LHC, all of the main Higgs boson production and decay modes have now been observed.

19th March 2019

ATLAS measures Higgs boson coupling to top quark in diphoton channel with full Run 2 dataset

At the Rencontres de Moriond (La Thuile, Italy), the ATLAS Collaboration presented an updated measurement of ttH production in the diphoton channel. The result examines the full Run 2 dataset – 139 fb-1 collected between 2015 and 2018 – to observe ttH production in a single channel with a significance of 4.9 standard deviations.

18th March 2019

ATLAS finds evidence of three massive vector boson production

Today, at the Rencontres de Moriond conference (La Thuile, Italy), the ATLAS collaboration released evidence for the simultaneous production of three W or Z bosons in proton–proton collisions at the Large Hadron Collider (LHC). The W and Z bosons are the mediator particles of the weak force – one of the four known fundamental forces – which is responsible for the phenomenon of radioactivity as well as an essential ingredient to our Sun's thermonuclear process.

18th March 2019

ATLAS observes light scattering off light

Light-by-light scattering is a very rare phenomenon in which two photons – particles of light – interact, producing again a pair of photons. The ATLAS Collaboration has reported the observation of light-by-light scattering with a significance beyond 8 standard deviations.

17th March 2019

A new data-collection method for ATLAS aids in the hunt for new physics

What do you do when you produce more data than you can handle? This might seem like a strange question for experimental physicists, but it’s a problem that the ATLAS detector faces every day. While the LHC continues to produce ever-higher rates of proton collisions, the detector can only record data at a fixed rate. Therefore, tough choices must be made about what events to keep. This is not a decision made lightly – what if the thrown-away data contain some long-sought new particles beyond those of the Standard Model.

21st March 2018

The exploration of the Higgs boson continues

Discovering the Higgs boson can be likened to finding a new continent. While a momentous event in itself, the most exciting part remains the exploration of the new land! In a new result presented today at the Rencontres de Moriond, the ATLAS collaboration examined the Higgs boson decaying into two W bosons

12th March 2018

Impressions from Moriond

The 52nd Rencontres de Moriond conference was held in La Thuile, Italy, from the 18 March to 1 April. The first week, which ran until 25 March, was devoted to the theme "Electroweak interactions and unified theories", while the second week was based on the theme of “QCD and high energy interaction”.

6th April 2017

ATLAS highlights from Moriond

At this year’s Rencontres de Moriond, the ATLAS collaboration presented the first results examining the combined 2015/2016 LHC data at 13 TeV proton–proton collision energy. Thanks to outstanding performance of the CERN accelerator complex last year, this new dataset is almost three times larger than that available at ICHEP, the last major particle physics conference held in August 2016.

2nd April 2017

Quest for the lost arc

Nature has surprised physicists many times in history and certainly will do so again. Therefore, physicists have to keep an open mind when searching for phenomena beyond the Standard Model.

21st March 2017

Particle-hunting at the energy frontier

There are many mysteries the Standard Model of particle physics cannot answer. Why is there an imbalance between matter and anti-matter in our Universe? What is the nature of dark matter or dark energy? And many more. The existence of physics beyond the Standard Model can solve some of these fundamental questions. By studying the head-on collisions of protons at a centre-of-mass energy of 13 TeV provided by the LHC, the ATLAS Collaboration is on the hunt for signs of new physics.

21st March 2017

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”

21st March 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

20th March 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.

19th March 2017

One does not simply give a talk at Moriond

The third day of the Moriond QCD conference was dedicated to quantum chromodynamics (QCD), the theory that describes strong interactions itself.

5th April 2016

Bumps in the light

Here we are at the second blog from the Moriond QCD conference and, as promised, I will discuss a bit of physics.

4th April 2016
4th April 2016

First impressions from the Moriond conference

My name is Mario Campanelli, and I am a physicist who has been working for about 9 years on the ATLAS experiment, as part of the academic staff of University College London. This is the first time I write a blog, but I do have quite an experience in communicating science to the public, having guided visitors around CERN since I started working there as a PhD student 20 years ago, and also having written two books for the general public. Since Saturday I have been in La Thuile, a mountain resort in the Italian Alps, for the Rencontres de Moriond - arguably the most important winter conference in particle physics.

24th March 2016

Searching beyond the Standard Model with photon pairs

The ATLAS Collaboration uses two selections in this search, one optimised for Higgs-like particles that are expected to have a strong signal compared to background with both photons in the central region of the detector (the “spin-0” selection) and a second optimised for graviton-like particles (the “spin-2” selection) which often have at least one photon close to the LHC proton beam axis.

22nd March 2016

Chasing after elusive B meson decays into muons

Almost four years following the discovery of the Higgs boson, LHC experiments are now more than ever exploring the possibility of new particles and new effects beyond the Standard Model.

22nd March 2016

Are there more Higgs bosons?

The results presented by the ATLAS collaboration during the Moriond Electroweak 2016 conference set new limits on a potential extended Higgs sector.

22nd March 2016

ATLAS presents new results at Moriond conference

This year’s 50th anniversary edition of the “Moriond Electroweak and Unified Theories” conference at La Thuile in Italy featured the presentation and discussion of 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.

21st March 2016

A week of firsts

The annual conference, Moriond, is in its 50th edition this year, and I’ve had the pleasure of coming down to Aosta in Italy to participate in the QCD session; for the first time. It’s actually a week of firsts for me. The conference organizers described it as being in a kind of “QCD confinement”.

7th April 2015
7th April 2015

Moriond Electroweak: physics, skiing and Italian food

If you’re a young physicist working in high energy physics, you realize very soon in your career that “going for Moriond” and “going to Moriond” are two different things, and that neither of the two means that you’re actually going to Moriond. This year’s “Moriond Electroweak” was held in the Italian mountain resort of La Thuile, and had a special significance.

30th March 2015

ATLAS further verifies Standard Model coupling/mass relationship of Higgs boson

The discovery of a Higgs Boson in 2012 by the ATLAS and CMS experiments marked a key milestone in the history of particle physics. It confirmed a long-standing prediction of the Standard Model, the theory that underlines our present understanding of elementary particles and their interactions.

27th March 2015

The scalar boson

The ATLAS experiment has released results confirming that the Higgs boson has spin 0 (it is a so-called “scalar”) and positive parity as predicted by the Standard Model, making it the only elementary scalar particle to be observed in nature.

26th March 2015

In search of rare Higgs boson production with top quarks

In proton-proton collisions, several processes can lead to the production of a Higgs boson. The most “frequent” process (which is about one collision in four billion!) is the fusion of two gluons, contained in the initial protons, into a Higgs boson through a “top-quark loop”. Least frequent is a mode where the Higgs boson is produced in association with a pair of top-quarks.

24th March 2015

Unread section opened in the Standard Model book

While others are worrying that new physics might be running out of corners (see Eve Le Ménédeu's blog) we should not forget that even within the book of the Standard Model there are completely unread chapters. The Standard Model draws its success from the fascinating fact that its basic energy density formula, called Lagrangian, is uniquely defined by just specifying three fundamental symmetries.

30th March 2014

Dark Matters

The winter conference season is well under way, and what better way to fill my first blog post than with a report from one of the premier conferences in particle and astroparticle physics: the Rencontres de Moriond.

24th March 2014
24th March 2014

The Neutrino Puzzle

Having explored the latest results on what we call 'heavy flavour' or physics of particles containing a b-quark (see The Penguin Domination by Jessica Levêque), we embarked on a much lighter subject: neutrinos.

22nd March 2014
22nd March 2014

No matter how hard you try... Standard is standard

The past two days of the Recontres de Moriond 2014 Electroweak conference have been very intense with many new experimental results, many insightful theoretical talks and many lively discussions. Since the topics cover neutrino experiments, astrophysical observations and Standard Model precision measurements, giving a summary is not an easy task. But I will try.

22nd March 2014

The Penguin Domination

This week features the 2014 Moriond Electroweak conference at La Thuile, Italy. More than a 100 particle physicists gather from all around the world. Started 50 years ago, this conference is still very valued, year after year, due to the high quality of the talks. The Moriond winter conference is one of the most exciting conferences, as all the particle physics experiments present their brand new results, but it is also appealing because of the mountains and the great Italian food.

18th March 2014

Moriond EW feedback

"Moriond", that's an important keyword in our collaboration. It's the winter deadline for many analyses, the occasion to see first results with the whole set of data collected in the past year. An important conference, one of the milestones of the year.

25th April 2013
25th April 2013

What we learned from ATLAS at Les Rencontres de Moriond 2013

Les Rencontres de Moriond, an important conference for the worldwide community of particle physicists, took place from 2-16 March 2013 in La Thuile, Italy. Of all the scientists present, 22 ATLAS physicists had been invited to reveal the experiment's latest findings. What did we learn from this new ATLAS physics harvest?

8th April 2013

ATLAS in the Italian Alps for the Rencontres de Moriond 2013

From March 2nd to March 16th 2013 the mythic "Rencontres de Moriond" is taking place in the Italian Alps at the La Tuile ski resort. For the 48th edition of this famous event, more than 420 physicists, theorists and experimentalists, young and more experienced, coming from the four corners of the planet get together in this pleasant environment to share their most recent results and ideas on particle physics. Twenty-two ATLAS physicists were invited to divulge the latest findings of the ATLAS Experiment.

27th February 2013

Moriond day 3: The day of the Higgs

(I'm not skipping day 2, about heavy flavors and my own talk, but I think today's topic merits a reshuffling)

8th March 2012

Moriond day 2: Inverse time dilation

I work with crazy particles. Dark matter is pretty weird, so are neutrinos seemingly, but what I search for blows it all away. Tuesday was the day of my presentation. The format for these young scientist presentations are 5 minutes and time for a single question afterwards. Trying to present a full picture of any analysis in that short a time is impossible; instead the idea is more like handing out a business card telling the audience what you work on in the hope that some will be interested and contact you informally afterwards.

6th March 2012

Moriond day 1: The outer limits

Not many trips take you to all ends of the world in one day, but that was nevertheless how it felt after the first talks at Moriond. Sunday and Monday have mainly featured presentations on neutrino and dark matter physics. Many of these experiments are placed in remote regions or deep under ground.

5th March 2012

Mountains of Physics

Experimentalists and theorists are gathering once more in the Alps at La Thuile, Italy, March 3-17 for the annual "Rencontres de Moriond" to discuss latest results in particle physics and cosmology.

5th March 2012

Mystical Moriond

As a young physicist not many conferences have the same mystical status as Rencontres de Moriond. This gathering of physicists from all areas of particle physics is one of most anticipated events of the year. More a gathering than a conference, Moriond started in 1966 and has inspired many similar events. Presentations, time for discussion and recreation is combined to inspire and foster collaboration and new ideas. Another element is the meeting between young and more experienced scientists. Nearly half of the talks are given by young participants below 35 like myself. I was invited by the ATLAS collaboration to present our latest results on a search for a type of long-lived particles that has meant a lot to me for the last two years.

3rd March 2012
3rd March 2012