Physics Briefings

Lepton transverse momentum distribution from the W→ μν selection

Of mesons and bosons

24th July 2015ATLAS is ready for detailed physics studies. The experiment used early data collected from the LHC’s Run 2 to calibrate its detectors. Measurements of the production and leptonic decay of certain particle resonances have shown that the detectors and software are working as expected. 

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Inclusive-jet cross sections as a function of the jet pT

First measurements set the stage for early searches of new physics

24th July 2015Jets are collimated sprays of hadrons generated from quarks and gluons, produced either directly in the proton-proton collision or as a part of the decay of W bosons, Z bosons, Higgs bosons, top quarks or new particles yet to be discovered. In fact, all W, Z and Higgs bosons decay most often to quarks which form jets. 

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Two-particle correlations

ATLAS measurements of the ridge in proton-proton collisions at 13TeV

24th July 2015Previous studies of two-particle angular correlations in proton-proton, proton-lead, and lead-lead collisions at the LHC have provided important insight on the physics of the particle production process. On 24 July, Atlas presented new preliminary measurements of two-particle correlations...

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The average charged-particle multiplicity as a function of the centre-of-mass energy

Early Run 2 results test event generator energy extrapolation

22nd July 2015On 23 July 2015, ATLAS presented its first measurements of soft strong interaction processes using charged particles produced in proton–proton collisions at 13 TeV centre-of-mass energy delivered by the Large Hadron Collider at CERN. These measurements were performed with a dataset collected beginning of June under special low-luminosity conditions.

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Display of one of the events selected as a candidate W’ event decaying to WZ.

Run I search for new massive bosons builds excitement for Run II

19th June 2015The ATLAS experiment is now taking data from 13 TeV proton-proton collisions. The increased collision energy and rate in these Run 2 collisions will allow physicists to carry out stronger tests of many theoretical conjectures, including several theories that predict more massive versions of force-carrying particles like the W and Z bosons.

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The coupling of the Higgs boson to fermions and bosons as a function of the particle’s mass.

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

27th March 2015The 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.

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Angular observables sensitive to the spin and parity of a Higgs boson decay.

The scalar boson

26th March 2015The 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.

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