ATLAS Collaboration

Precise measurement of the Higgs boson mass

The ATLAS Collaboration has analyzed 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.

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Measuring top production in the LHC

Using the full data sample from the LHC’s first run of proton-proton collisions, ATLAS has measured the production rate of top and anti-top quarks.

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New evidence for top quark pairs produced with W or Z bosons

Evidence for the production of a W or Z boson together with a top quark pair, referred to as tt̄W and tt̄Z processes, has been found in the ATLAS analysis of the 8 TeV data from the LHC’s first run.

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New results from ATLAS at Quark Matter 2014

ATLAS has prepared a variety of new results for the Quark Matter 2014 conference using lead-lead (Pb+Pb) and proton-lead (p+Pb) data collected during Run1. 

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ATLAS to present new results at Moriond

ATLAS collaborators and other scientists will be presenting new findings at the two weeks of the Rencontres de Moriond conferences, which starts on 15 March, at La Thuile in Italy.

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Englert and Higgs get the Nobel

On 8 October, the 2013 Nobel Prize in physics was awarded to Professors François Englert and Peter Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN’s Large Hadron Collider". 

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New searches for SUSY

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

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New results on the properties of the top quark

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

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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?

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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.

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