At this week’s Higgs2024 conference, the ATLAS Collaboration unveiled the first LHC search for tri-Higgs production – a process over 600,000 times rarer than the production of a single Higgs boson.

ATLAS researchers are using innovative new techniques in their analysis of off-shell Higgs-boson production.

New measurements by the ATLAS Collaboration show that studying Higgs-boson decays into tau-lepton pairs can reveal not only its interactions with fermions, but also give insights into Higgs-boson production at the LHC. ATLAS researchers performed two kinds of cross-section measurements in their new analysis of Higgs-boson decays to tau leptons.

At the recent International Conference on High-Energy Physics (ICHEP) 2024, the ATLAS Collaboration presented a new measurement of the ttH(bb) process using the same Run-2 dataset, achieving a factor of two better expected ttH signal significance compared to the previous result.

The ATLAS Collaboration has just released the world’s most precise study of the Higgs boson’s interaction with bottom quarks and charm quarks. This new result is a re-analysis of data collected during Run 2 of the LHC (2015-2018). ATLAS researchers examined Higgs-boson decays to bottom and charm quarks (H→bb and H→cc) implementing significantly improved analysis techniques.

The ATLAS Collaboration has made a significant advancement in the understanding of the Higgs boson by investigating its production in association with W or Z bosons (known as “VH production”), where the Higgs boson decays to bottom quarks. For the first time, LHC researchers have studied VH production in a fully hadronic final state.

In a new analysis from the ATLAS Collaboration, physicists merged five di-Higgs studies of LHC Run 2 data. By combining the power of all these decay channels, researchers achieved the most sensitive probe of di-Higgs production and the Higgs self-coupling.

The ATLAS Collaboration has just published a search for two new Higgs bosons, X and S, that would interact with the Standard-Model Higgs boson.

If spotting one Higgs boson is interesting, what happens when you spot two? ATLAS researchers are looking for the production of two Higgs bosons using a new technique.

The ATLAS Collaboration mourns the passing of renowned physicist Peter Higgs, whose theoretical work on elucidating the fundamental spontaneous symmetry-breaking mechanism by which elementary particles acquire mass reshaped our understanding of the Universe.

In a new result, the ATLAS Collaboration reports the first evidence of a Higgs boson produced in association with a leptonically-decaying W or Z boson and decaying into a pair of tau leptons.

The ATLAS Collaboration has released two brand-new results searching for di-Higgs events in the full LHC Run-2 dataset. In one, researchers looked for events where one Higgs boson decays into two bottom quarks and the other decays into two photons. In the other, they looked for events where one Higgs boson decays into two bottom quarks, and the other into two tau leptons or W/Z bosons, which subsequently decay into leptons.

The new result is the most precise determination of the Higgs-boson mass yet, achieving a remarkable accuracy of 0.09% for this fundamental parameter.

This week, at the Lepton-Photon Conference in Melbourne (Australia), the ATLAS Collaboration presented its measurement of the Higgs-boson mass in studies of Higgs decays to two photons using the full LHC Run 2 dataset (“H→yy” or the diphoton channel), and a new combination of this measurement with the 2022 measurement of the Higgs-boson mass in studies of the Higgs decays to four leptons (the “H→4l channel”).

The ATLAS and CMS Collaborations have joined forces to report first evidence of the Higgs boson decaying into a Z boson and a photon.

ATLAS and CMS teamed up to find the first evidence of the rare process in which the Higgs boson decays into a Z boson, the electrically neutral carrier of the weak force, and a photon, the carrier of the electromagnetic force.

The ATLAS Collaboration just released new measurements of the production rate (or cross-section) of Higgs bosons at 13.6 TeV using data collected in the second half of 2022.

Scientists working on the Large Hadron Collider at CERN breathed a sigh of relief today, as the world-renowned Higgs boson returned to its showcase in the heart of the laboratory.

In the new results presented at the Moriond conferences, the ATLAS Collaboration tested the CP invariance of Higgs-boson interactions with vector bosons (W or Z bosons).

In a highlight result presented at the Higgs 2022 conference, the ATLAS Collaboration studied the production of off-shell Higgs bosons with a high invariant mass decaying into two on-shell Z bosons using the data collected during LHC Run 2 (2015-2018). For their new search, ATLAS physicists focused on events where the two Z bosons decay into four charged leptons (ZZ→4l channel) or two charged leptons plus two neutrinos (ZZ→ 2l2v channel), as they offered the highest signal sensitivity.

The ATLAS Collaboration has been looking for signs of dark photons in data collected by the experiment during LHC Run 2 (2015-2018). Their newest search targets, for the first time in ATLAS, the production of a Higgs boson in association with a Z boson, with subsequent decay of the Higgs into a photon and a dark photon.

In the most recent effort to constrain the Higgs self-coupling constant, ATLAS physicists used the full Run 2 dataset (collected during 2015-2018) to perform a combined study on the production of a single Higgs boson and two Higgs bosons. This single-Higgs analysis was featured in a paper released in Nature today, looking back on 10 years of Higgs boson research at the ATLAS Experiment

The ATLAS Collaboration at CERN has released its most comprehensive overview of the Higgs boson. The new paper, published in the journal Nature, comes exactly ten years after ATLAS announced the discovery of the Higgs boson. In celebration of this anniversary, a special all-day symposium on the Higgs boson is currently underway at CERN.

The collaborations have used the largest samples of proton–proton collision data recorded so far by the experiments to study the unique particle in unprecedented detail.

The ATLAS Collaboration has just released a new measurement of the CP properties of H→ττ interactions. The study of H→ττ allows researchers to understand the CP-nature of Higgs boson interactions.

The ATLAS Collaboration performed a new search for exotic Higgs-boson decays using the full dataset of 13 TeV proton-proton collisions delivered by the LHC between 2015 and 2018.

Many theories suggest that the Higgs boson discovered in 2012 by the ATLAS Experiment is but the first to be observed from a larger Higgs family. A new ATLAS analysis searches for the presence of a new singly-charged Higgs boson.

According to the Standard Model, most particles get their mass through an interaction with the Higgs field. If dark-matter particles acquire their mass in the same way, a Higgs boson created in an LHC collision might sometimes decay into a pair of “invisible” dark-matter particles. The ATLAS Collaboration has released a new search for invisible Higgs-boson decays using the full Run-2 dataset.

Physicists from the ATLAS Collaboration have combined two measurements of the interaction strength of the Higgs boson with two different pairs of quarks. This allows physicists to test a hypothesis that the Higgs boson interacts with charm quarks (which are second-generation quarks) in the same way it interacts with beauty quarks (third-generation quarks).

The ATLAS Collaboration has released updated measurements of the Higgs boson properties using the full LHC Run-2 dataset (recorded 2015-2018).

According to the Standard Model, the Higgs boson can interact with itself, resulting in the simultaneous production of two Higgs bosons ("di-Higgs production"). In a new result, the ATLAS Collaboration combines three di-Higgs decay channels to reach the best limits yet on di-Higgs production.

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.

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'.

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.

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.

In the post-Higgs discovery era, scientists at the Large Hadron Collider (LHC) have been hard at work studying the Higgs boson’s properties. One property that remains to be experimentally verified is whether the Higgs boson can couple to itself (self-coupling).

The Higgs boson reveals its properties to the outside world twice: during production and decay. ATLAS’ new result studies the Higgs boson at both of these moments, looking at its production via two different methods and its subsequent decay into two W bosons.

ATLAS finds first evidence of the Higgs boson decaying to two leptons and a photon. This is one of the rarest Higgs boson decays yet seen at the LHC, with striking features that presented unique challenges for the ATLAS experiment.

New results from the ATLAS Collaboration focus on different production modes of the Higgs boson decaying into b-quarks, capitalising on the power of machine learning to better discriminate this particular process from other proton collision events.

A new result from the ATLAS Collaboration, released for the Higgs 2020 conference, aims at enriching the Higgs picture by studying its WW* decays.

One of the great unexplained mysteries is the nature of dark matter. So far, its existence has only been established through gravitational effects observed in space; no dark-matter particles with the needed properties have (yet) been detected. Could the Higgs boson be the key to their discovery?

ATLAS scientists are implementing a new strategy in the search for physics beyond the Standard Model – one that combines measurements across the full spectrum of the Collaboration's research programme.

The ATLAS and CMS experiments at CERN announce new results which show that the Higgs boson decays into two muons. These new results have pivotal importance for fundamental physics because they indicate for the first time that the Higgs boson interacts with second-generation elementary particles.

Physicists can study Higgs-boson couplings in several ways: by measuring the rates of different Higgs boson production mechanisms and decays, and also by studying the particle’s kinematic properties. The ATLAS Collaboration has just presented precise new measurements of these key quantities. Several of these measurements were updated to use the full LHC Run 2 dataset (2015–2018), to provide the best precision to date.

In the contest for the heaviest known elementary particle, the top quark and Z boson rank first and third, respectively. When a proton–proton collision produces a top-quark pair together with a Z boson – a process known as ttZ production – their total mass can reach an impressive 440 GeV! The discovery of this highly energetic process thus required the record collision energy and rate of the LHC; no previous collider could come close.

The ATLAS Collaboration has released a new paper on the search for the Higgs-boson decay to a pair of muons. The new study uses the entire dataset collected by the ATLAS experiment during Run 2 of the LHC (2015–2018) to give a first hint of this elusive process.

Could the Higgs boson decay into dark matter? As dark matter does not interact directly with the ATLAS detector, physicists look for signs of “invisible particles”, inferred through momentum conservation of the proton–proton collision products. The ATLAS Collaboration searched the full LHC Run 2 dataset, setting the strongest limits on the Higgs boson decaying to invisible dark-matter particles to date.

The ATLAS Collaboration has just released a new result searching for the Higgs-boson decay to a Z boson and a photon. This result uses the full LHC Run 2 dataset, analysing almost four times as many Higgs-boson events as the previous ATLAS result.

When a particle is transformed into its antiparticle and its spatial coordinates inverted, the laws of physics are required to stay the same – or so we thought. This symmetry – known as “CP symmetry” (Charge conjugation and Parity symmetry) – was considered to be exact until 1964, when a study of the kaon particle system led to the discovery of “CP violation”. In a new result presented today, the ATLAS Collaboration performed a direct test of the CP properties of the interaction between the Higgs boson and top quarks. The result is based on an analysis of the full LHC Run-2 dataset, looking at collision events where the Higgs boson is produced in association with one or two top quarks, and in turn decays into two photons.

Two years ago, the Higgs boson was observed decaying to a pair of beauty-quarks (H→bb), moving its study from the “discovery era” to the “measurement era”. In new results presented today, the ATLAS Collaboration studied the full LHC Run 2 dataset to give an updated measurement of H→bb, where the Higgs boson is produced in association with a vector boson (W or Z).

Does the Higgs boson follow all of the rules set by the Standard Model? Since discovering the particle in 2012, the ATLAS and CMS Collaborations have been hard at work studying the behaviour of the Higgs boson. Any unexpected observations could be a sign of new physics beyond the Standard Model.

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.

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.

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.

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) is scheduled to begin colliding protons in 2026. This major improvement to CERN’s flagship accelerator will increase the total number of collisions in the ATLAS experiment by a factor of 10. To cope with this increase, ATLAS is preparing a complex series of upgrades including the installation of new detectors using state-of-the-art technology, the replacement of ageing electronics, and the upgrade of its trigger and data acquisition system.

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.

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.

Beams in the Large Hadron Collider came to a stop today, closing out four years of record-breaking operation for the ATLAS experiment. Run 2 saw the extraordinary exploration of the high-energy frontier, as the ATLAS experiment brought new understanding of particle physics.

The Brout-Englert-Higgs (BEH) mechanism is at the core of the Standard Model, the theory that describes the fundamental constituents of matter and their interactions. It introduces a new field, the Higgs field, through which the weak bosons (W and Z) become massive while the photon remains massless. The excitation of this field is a physical particle, the Higgs boson, which was discovered by the ATLAS and CMS collaborations in 2012.

The ATLAS Collaboration at CERN’s Large Hadron Collider (LHC) has – at long last – observed the Higgs boson decaying into a pair of bottom (b) quarks. This elusive interaction is predicted to make up almost 60% of the Higgs boson decays and is thus primarily responsible for the Higgs natural width. Yet it took over six years after the 2012 discovery of the Higgs boson to accomplish this observation.

While the discovery of the Higgs boson at the Large Hadron Collider (LHC) in 2012 confirmed many Standard Model predictions, it has raised as many questions as it has answered. For example, interactions at the quantum level between the Higgs boson and the top quark ought to lead to a huge Higgs boson mass, possibly as large as the Planck mass (>10¹⁸ GeV). So why is it only 125 GeV? Is there a mechanism at play to cancel these large quantum corrections caused by the top quark (t)? Finding a way to explain the lightness of the Higgs boson is one of the top (no pun intended) questions in particle physics.

Today, at the 2018 International Conference on High Energy Physics in Seoul, the ATLAS experiment reported a preliminary result establishing the observation of the Higgs boson decaying into pairs of b quarks, furthermore at a rate consistent with the Standard Model prediction.

Higgs boson couplings manifest themselves in the rate of production of the Higgs boson at the LHC, and its decay branching ratios into various final states. These rates have been precisely measured by the ATLAS experiment, using up to 80 fb^–1 of data collected at a proton-proton collision energy of 13 TeV from 2015 to 2017. Measurements were performed in all of the main decay channels of the Higgs boson: to pairs of photons, W and Z bosons, bottom quarks, taus, and muons. The overall production rate of the Higgs boson was measured to be in agreement with Standard Model predictions, with an uncertainty of 8%. The uncertainty is reduced from 11% in the previous combined measurements released last year.

Many questions in particle physics are related to the existence of particle mass. The “Higgs mechanism,” which consists of the Higgs field and its corresponding Higgs boson, is said to give mass to elementary particles.

Physicists from around the globe assembled this week at the Centre Domenico in Bologna, Italy, the site of Europe’s oldest university, to attend the sixth annual conference on Large Hadron Collider Physics (LHCP2018). The 425 participants enjoyed picturesque architecture, world-renowned cuisine, and a full menu of recent physics results from the LHC. A sample platter of a few of the tasty morsels is presented.

A decisive property of the Higgs boson is its affinity to mass. The heavier a particle is, the stronger the Higgs boson will couple to it. While physicists have firmly established this property for heavy W and Z bosons (force carriers), more data are needed to measure the Higgs boson coupling to the heavy fermions (matter particles). These interactions, known as Yukawa couplings, are very interesting as they proceed through a quite different mechanism than the coupling to force-carrying bosons in the Standard Model.

The ATLAS Collaboration at CERN has announced the observation of Higgs bosons produced together with a top-quark pair. Observing this extremely rare process is a significant milestone for the field of High-Energy Physics. It allows physicists to test critical parameters of the Higgs mechanism in the Standard Model of particle physics.

According to the Standard Model, quarks, charged leptons, and W and Z bosons obtain their mass through interactions with the Higgs field, whose fluctuation gives rise to the Higgs boson. To test this theory, ATLAS takes high-precision measurements of the interactions between the Higgs boson and these particles. While experiments had observed and measured the Higgs boson decaying to pairs of W or Z bosons, photons or tau leptons, the Higgs coupling to quarks had – until now – not been observed.

The ATLAS Collaboration at CERN has released new studies of the Higgs boson using 13 TeV data collected in 2015 and 2016. The results further corroborate the Standard Model nature of the Higgs boson, and open doors to fresh searches for new physics.

The ATLAS collaboration has released a set of comprehensive results that illuminate the properties of the Higgs boson with improved precision, using its decay into two photons with LHC collisions recorded at a centre-of-mass energy of 13 TeV.

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

The ATLAS collaboration has presented evidence of “ttH production”, a rare process where a pair of top quarks emits a Higgs boson. Observing this process would provide new insight into the Higgs mechanism and allow for new studies of how unknown physics might (or might not) change the behaviour of this fundamental particle.

Since discovering a Higgs boson in 2012, the ATLAS and CMS collaborations have been trying to understand whether this new particle is the Higgs boson as predicted by the Standard Model, or a Higgs boson from a more exotic model containing new, as yet undiscovered, particles. The answer lies in the properties of the Higgs boson.

With the huge amount of proton–proton collisions delivered by the LHC in 2015 and 2016 at the increased collision energy of 13 TeV, ATLAS has entered a new era of Higgs boson property measurements. The new data allowed ATLAS to perform measurements of inclusive and differential cross sections using the “golden” H->ZZ*->4l decay.

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.

The LHC’s jump in energy to 13 TeV in Run 2, together with the copious amount of collisions delivered over the last 12 months, has allowed the ATLAS experiment to collect a data sample that is more than equivalent to the one collected during Run 1.

The ATLAS experiment has been searching for the process in which a pair of top quarks is produced, where one is a “virtual” particle that emits a Higgs boson on the way to becoming a “real” particle. This process is referred to as ttH production after the particles that are produced.

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

Today, at the Large Hadron Collider Physics conference (LHCP2015), the ATLAS and CMS collaborations presented the most precise measurements yet of Higgs boson properties. By combining Run 1 data from both experiments, the new measurements paint a clear picture of how the Higgs boson is produced, decays, and interacts with other particles.

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.

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.

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.

On 17 March, ATLAS presented their latest Higgs physics results at an LHC seminar at CERN from data collected during the LHC's first run. The updated results include searches for the Higgs boson in association with top quarks, measurements of the spin and parity, and improved and combined coupling measurements, all showing good compatibility with Standard Model predictions. These results are also being presented at the 50th Rencontres de Moriond ElectroWeak conference, in La Thuile, Italy, this week.

Today during the 50th session of “Rencontres de Moriond” in La Thuile Italy, ATLAS and CMS presented for the first time a combination of their results on the mass of the Higgs boson.

The dataset from the ATLAS Higgs Machine Learning Challenge has been released on the CERN Open Data Portal.

Higgs Hunters, the first particle physics venture on Zooniverse, a citizen science project, has been launched in collaboration with the University of Oxford, New York University and the ATLAS Experiment. Higgs Hunters invites online volunteers to participate in studying the properties of the new boson, which may hold clues as to what lies beyond our current understanding of the universe.

The winner of the four-month long Higgs Machine Learning Challenge, launched on 12 May, is Gábor Melis from Hungary, followed closely by Tim Salimans from The Netherlands and Pierre Courtiol from France. They will receive cash prizes, sponsored by Paris-Saclay Centre for Data Science and Google, of $7000, $4000, and $2000 respectively. The three winners have been invited to participate at the Neural Information Processing Systems conference on 13 December in Canada.

The Standard Model makes many different predictions regarding the production and decay properties of the Higgs boson, most of which can be tested at the Large Hadron Collider (LHC). Since the discovery, experimentalists from the ATLAS collaboration have analysed the complete dataset recorded in 2011 and 2012, have improved the calibration of the detector, and have increased substantially the sensitivity of their analyses.

The discovery of the Higgs boson by the ATLAS and CMS collaborations in 2012 marked a new era in particle physics because it completed the Standard Model and gave us another tool to explore territories beyond. The Standard Model predicts precisely the interactions of the Higgs boson to all other elementary particles once its mass is measured.

ATLAS has measured properties of events likely to contain a Higgs boson, in order to get a better understanding of the frequency and manner in which they are produced. The study specifically examines the fiducial and differential cross sections for Higgs bosons that decay into two photons or into two Z bosons, using proton-proton collisions recorded by ATLAS in 2012.

ATLAS physicists have studied the “shadow” of the Higgs boson far above its mass peak in an analysis of the full sample of 8 TeV proton-proton collisions delivered by the LHC in 2012. The study involves Higgs boson decays into two Z bosons, which themselves decay into four charged leptons or two charged leptons plus two neutrinos. Among other interesting properties, it provides new insight into the lifetime, or natural width, of the Higgs boson.

The ATLAS & CMS experiments celebrate the second anniversary of the discovery of the Higgs boson. Here, are some images of the path from the LHC's startup to the Nobel Prize, featuring a musical composition by Roger Zare, performed by the Donald Sinta Quartet, called 'LHC'. Happy Discovery Day!

It’s been two years since the ATLAS and CMS experiments at CERN jointly announced the discovery of a new boson consistent with the Higgs particle of the Standard Model. Since then, the Higgs boson has been intensely examined. We’ve measured its spin, its mass, its lifetime, and observed its decay into bosons and fermions. In the next run of the Large Hadron Collider, we hope to learn more about how it interacts with other particles and to make many more precise measurements of its properties. By doing, we hope to extend the limits of our current understanding of the fundamental components of nature, and to seek clues for discovery.

The ATLAS Collaboration has analysed its full Run 1 data sample of seven and eight TeV (tera electron Volts) proton-proton collisions delivered by the Large Hadron Collider (LHC), to produce an accurate measurement of the Higgs boson mass. The Higgs boson resonance appears as a narrow peak in the mass spectra of its decays to two photons or to four charged leptons, as shown in the two figures below.

It's been four weeks since the four-month long Higgs Machine Learning Challenge was announced. Almost 700 teams have signed up and more than 200 have beaten the in-house benchmark already.

ATLAS presented new results at the Large Hadron Collider Physics (LHCP) Conference in Columbia University, New York, 2 to 7 June. Many new searches and improved measurements were presented, among which were an updated Higgs boson mass measurement, a search for double Higgs boson production and new searches for Supersymmetry and exotic phenomena.

Friday was the last occasion for Moriond participants to see new results on specific physics topics since Saturday is reserved for summary talks. The topic was 'Beyond the Standard Model' -- a very large subject, which covers an incredible number of theoretical models, from Supersymmetry to Two-Higgs-Doublet Models, two of the most discussed topics of the day.

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.

The ATLAS experiment released preliminary results on 26 Nov 2013 that show evidence, with a significance of 4.1 standard deviations that the Higgs boson decays to two taus, which are fermions. This is exciting news. But what makes this measurement important?

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?

On 31 July, 2012, the ATLAS Experiment submitted a scientific paper describing the discovery of a new particle consistent with the Higgs Boson to the journal Physics Letters B.

We have discovered a particle. It is perhaps the particle everybody has been looking for but, for now, let us just call it a particle possibly known as the Higgs.

Where to begin? The 4th of July, 2012 will remain burned in the memories of those of us fortunate to be delegates at this historic 36th International Conference on High Energy Physics (#ICHEP2012) in beautiful Melbourne, Australia.

Good morning science addicts and everyone! What a special day at CERN today! Indeed, the ATLAS and CMS experiments have just released some outstanding results and observations about the search for the Higgs boson, and the ATLAS and CMS spokespersons (Fabiola Gianotti, and Joe Incandela) just presented those results in the main auditorium at 9 a.m (CERN time).

On 4 July, 2012, the ATLAS experiment presented a preview of its updated results on the search for the Higgs Boson. The results were shown at a seminar held jointly at CERN and via video link at ICHEP, the International Conference for High Energy Physics in Melbourne, Australia, where detailed analyses will be presented later this week. At CERN, preliminary results were presented to scientists on site and via webcast to their colleagues located in hundreds of institutions around the world.

The ATLAS Experiment will be presenting its most recent results from searches for the Higgs Boson at the LHC in a dedicated seminar to be held at CERN on 4 July at 9:00 CET.

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

“If it’s just a fluctuation of background, it will take a lot of data to kill.” Dr. Fabiola Gianotti, spokesperson for the ATLAS collaboration, made this statement on Dec. 13, 2011 during a special seminar I attended at CERN. Within the minute that followed, I hurriedly concocted a tweet, tacked on #Higgs and #CERN hashtags, and sent Fabiola’s weighty comment out onto the WWW.

The results on Standard Model (SM) Higgs searches that ATLAS reported at a CERN seminar on December 13, 2011, have now been submitted for publication in three papers.

The latest update of the ATLAS searches for the Standard Model Higgs boson was presented at a CERN seminar on December 13, 2011. As stated in the CERN press release, the new ATLAS and CMS results are "sufficient to make significant progress in the search for the Higgs boson, but not enough to make any conclusive statement on the existence or non-existence of the elusive Higgs. Tantalising hints have been seen by both experiments in the same mass region, but these are not yet strong enough to claim a discovery."

The Higgs Boson is the only missing piece in the Standard Model of particle physics and its search is undoubtedly one of the most important searches in the history of physics. The Higgs boson is the generator of all elementary particle masses in nature. The mass of the Higgs boson itself is unknown, and before the LHC it was searched for in previous experiments but not found. LHC experiments have produced excellent results since the start of the data taking. In ATLAS and CMS a discussion was initiated about a year ago to combine the Higgs search results from both experiments. The framework and the procedure to combine results had to be defined and agreed upon before the combined analysis could proceed.

Physicists are confident they will soon be able to answer a fundamental question at the LHC: how do particles acquire mass? The simplest answer, the one given in the Standard Model of the fundamental particles, is that a single particle, the Higgs boson, endows the other particles and itself with mass. The Higgs boson does this by means of the "Higgs mechanism", which involves breaking a symmetry that would leave all Standard Model particles massless if it were not broken. However the Higgs boson is not the only way the Higgs mechanism might work.

Today we witnessed a landmark LHC first: At the HCP conference in Paris, friendly rivals, the ATLAS and CMS collaborations, came together to present a joint result! This ATLAS-CMS combined Higgs search was motivated by the fact that pooling the dataset increases our chances of excluding or finding the Higgs boson over those of a single experiment. This is the first example of this kind of scientific collaboration at the LHC, and the success of the whole endeavor hinged on a whole host of thorny issues being tackled…

Perhaps the most anticipated result of the LHC involves the search for the Higgs boson, the only particle predicted by the Standard Model (SM) that has not yet been seen by experiments. The Higgs boson helps explain how elementary particles acquire mass. If the SM Higgs boson exists it will be produced at the LHC and swiftly decay into various known and well-studied particles, with the dominant decay products depending on the actual Higgs mass. ATLAS and CMS search for the SM Higgs boson using a range of decay products: two photons; two tau leptons; two b quarks; two W bosons; and two Z bosons. Analysing all these channels ensures that the search is sensitive to observing the Higgs irrespective of its mass.

The Lepton Photon 2011 conference began on Monday in Mumbai, India. Over 400 physicists from all over the world (including me!) gathered to hear the latest results. One result in particular -- news on the search for the Higgs boson -- was foremost in people's minds, and rather than prolong the suspense further, the talks on the Higgs were scheduled right after the welcoming speeches.

The ATLAS experiment has continued to record data and to refine the analyses in the search for the Higgs boson and many other exciting signatures of new physics. The latest results are being presented at the Lepton Photon 2011 symposium in Mumbai, India, 22-27 August 2011. Since the previous meeting (the European Physical Society — EPS, Grenoble, France, 21-27 July 2011), the LHC has almost doubled the data provided to ATLAS.

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.