Briefings
Shedding light with jets from the dark side
Researchers at the ATLAS Experiment are searching for a hidden “dark sector”, a realm of new sets of particles and forces that interact very weakly with the known matter, potentially producing elusive and puzzling signatures. In two new results, ATLAS physicists hunted for dark-sector physics using these distinctive jet signatures.
Exploring the W boson at extreme mass scales
ATLAS physicists have measured the cross section for W bosons with transverse masses between 200 GeV and 5 TeV.
ATLAS probes the Higgs mechanism in the scattering of W boson
The ATLAS Collaboration reported the first evidence – with 3.3σ significance – of vector boson scattering involving longitudinally polarised, same-sign W bosons
Displaced but not unnoticed: ATLAS in pursuit of Long-Lived Particles
In a new study submitted to Physical Review D, scientists at the ATLAS experiment leveraged the muon spectrometer’s size and precision tracking capabilities to search for neutral LLPs by identifying displaced decay vertices.
Learning from the Tau
The ATLAS Collaboration has published two new papers investigating the production of tau leptons in high energy proton-proton collisions.
Boosting precision of top-quark mass measurement with ATLAS
The ATLAS Collaboration at CERN performed its most precise single measurement of the mass of the top quark, using high-transverse-momentum (“boosted”) top quarks.
Massive vector bosons also come in triplets
The ATLAS Collaboration announces the first observation of “VVZ production” – a rare combination of three massive vector bosons produced simultaneously at the LHC.
The measurement of a lifetime
This week, the ATLAS Collaboration announced a new high-precision measurement of the lifetime of the B0 meson. The B0 meson is composed of a bottom quark and a down antiquark. Measurements of its lifetime – the average time it exists before decaying – provide an exceptional probe of physics processes beyond the Standard Model.
ATLAS observes top quarks in lead-lead collisions
The ATLAS Collaboration at CERN has observed top-quark pair production in lead-lead ion collisions, marking the first observation of this process in nucleus-nucleus interactions.
Why stop at two? ATLAS hunts for the production of three Higgs bosons
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.
Cracking open the Higgs shell
ATLAS researchers are using innovative new techniques in their analysis of off-shell Higgs-boson production.
Advancements in particle tagging accelerate the search for new particles
The ATLAS Collaboration has released three major searches for new-physics phenomena, all utilising new advancements in particle tagging.
Decoding top quarks: Precision in heavy-flavour partner production
Two new studies from the ATLAS Collaboration explore how top-quark pairs are produced alongside heavy-flavour quarks, like bottom and charm.
Unveiling Higgs-boson production properties using tau-lepton pairs
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.
Transforming bottom-jets: machine learning for improved bottom-jets measurements
At the BOOST 2024 conference, the ATLAS Collaboration presented a new technique that employs artificial intelligence (AI) to refine jet calibration, specifically focusing on jets originating from bottom quarks (b-jets).
Breaking through (jet) barriers
As the most abundantly produced object in the ATLAS experiment, jets are critical to understanding a number of physics processes. In new results presented at the BOOST 24 conference in Genova (Italy), ATLAS scientists detailed two innovative approaches for more accurately quantifying jet properties.
Breaking “R-parity” in new searches for supersymmetry
At the recent ICHEP 2024 conference held in Prague (Czech Republic), ATLAS physicists presented two innovative searches for R-parity-violating SUSY using data collected during the Run 2 of the LHC (2015 to 2018).
ATLAS releases precise new measurement of Higgs boson production in association with top quarks
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 beauty and the charm of the Higgs boson
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.
ATLAS probes uncharted territory with improved trigger
The ATLAS Collaboration has released its first search for new physics phenomena at the highest-ever collision energy of 13.6 TeV, targeting exotic events with two “displaced” leptons.
Hunting for magnetic monopoles with the Universe's strongest magnetic fields
In a new result from the ATLAS Collaboration, physicists analysed the first Run-3 heavy-ion collision data collected in the autumn of 2023. Specifically researchers looked at “ultraperipheral” collisions, where ions pass at a distance precluding hadronic interactions yet close enough to interact through electromagnetic fields.
Jetting into a new era of Higgs studies
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.
ATLAS searches for the building blocks of dark matter
Researchers at the ATLAS Experiment release the first-ever direct search for new composite dark particles called dark mesons, presented this week at the Large Hadron Collider Physics (LHCP) Conference in Boston.
ATLAS chases long-lived particles with the Higgs boson
In a new study submitted to Physical Review Letters, ATLAS scientists used a new algorithm to search for long-lived particles (LLP) produced in the decay of Higgs bosons. These LLPs may leave a distinct signature of one or more hadronic “jets” of particles originating at a significantly displaced position from the proton–proton collision point.
Looking for the extended family of the Higgs boson
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.