Search results

Correlations in azimuthal angle extending over a long range in pseudorapidity between particles, usually called the “ridge” phenomenon, were discovered in heavy-ion collisions, and later found in pp and p–Pb collisions. In large systems, they are thought to arise from the expansion (collective flow) of the produced particles. Extending these measurements over a wider range in pseudorapidity and fi

Differential cross-sections are measured for the production of four charged leptons in association with two jets. These measurements are sensitive to final states in which the jets are produced via the strong interaction as well as to the purely-electroweak vector boson scattering process. The analysis is performed using proton-proton collision data collected by ATLAS at s = 13 TeV and with an int

X-ray tomography is a well established technique for investigating three-dimensional bulk structures across scales, from macroscopic samples down to their microscopic constituents. The addition of a temporal dimension through dynamic, time-resolved acquisition results in four-dimensional datasets whose complexity often exceeds the processing capabilities of existing image analysis tools. To addres

Semi-visible jets, with a significant contribution to the event's missing transverse momentum, can arise in strongly interacting dark sectors. This results in an event topology where one of the jets can be aligned with the direction of the missing transverse momentum. The first search for semi-visible jets produced via a t-channel mediator exchange is presented. The analysis uses proton-proton col

A search for nonresonant Higgs boson pair production in the bb¯γγ final state is performed using 140 fb−1 of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. This analysis supersedes and expands upon the previous nonresonant ATLAS results in this final state based on the same data sample. The analysis strategy is optimi

This letter presents a search for narrow, high-mass resonances in the Zγ final state with the Z boson decaying into a pair of electrons or muons. The s=13 TeV pp collision data were recorded by the ATLAS detector at the CERN Large Hadron Collider and have an integrated luminosity of 140 fb−1. The data are found to be in agreement with the Standard Model background expectation. Upper limits are set

This paper presents the observation of four-top-quark (tt¯ tt¯) production in proton-proton collisions at the LHC. The analysis is performed using an integrated luminosity of 140 fb - 1 at a centre-of-mass energy of 13 TeV collected using the ATLAS detector. Events containing two leptons with the same electric charge or at least three leptons (electrons or muons) are selected. Event kinematics are

The transverse momentum (pT) and centrality dependence of the nuclear modification factor RAA of prompt and non-prompt J/ψ, the latter originating from the weak decays of beauty hadrons, have been measured by the ALICE collaboration in Pb–Pb collisions at sNN = 5.02 TeV. The measurements are carried out through the e+e− decay channel at midrapidity (|y| < 0.9) in the transverse momentum region 1.5

A search for pair production of squarks or gluinos decaying via sleptons or weak bosons is reported. The search targets a final state with exactly two leptons with same-sign electric charge or at least three leptons without any charge requirement. The analysed data set corresponds to an integrated luminosity of 139 fb−1 of proton-proton collisions collected at a centre-of-mass energy of 13 TeV wit

This paper presents a search for a new Z′ resonance decaying into a pair of dark quarks which hadronise into dark hadrons before promptly decaying back as Standard Model particles. This analysis is based on proton-proton collision data recorded at s = 13 TeV with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to an integrated luminosity of 139 fb−1. After sele

The identification of jets originating from quarks and gluons, often referred to as quark/gluon tagging, plays an important role in various analyses performed at the Large Hadron Collider, as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced background. This paper describes the measurement of the efficiencies of quark/gluo

Classical model reduction techniques project the governing equations onto a linear subspace of the original state space. More recent data-driven techniques use neural networks to enable nonlinear projections. While those often enable stronger compression, they may have redundant parameters and lead to suboptimal latent dimensionality. To overcome these issues, we propose a multistep algorithm that

In this paper, we investigate how adaptive time-integration strategies can be effectively combined with parallel-in-time numerical methods for solving systems of ordinary differential equations. Our focus is particularly on their influence on tolerance proportionality. We examine various grid-refinement strategies within the multigrid reduction-in-time (MGRIT) framework. Our results show that a si

Context. The young β Pictoris system has been monitored with high-resolution optical spectrographs for decades. These observations have revealed strongly variable stochastic absorption in the Ca II H&K lines attributed to infalling cometary bodies. Aims. Since 2003, over 9000 HARPS observations of β Pictoris have been taken, and many of these have not yet been used for exocomet studies. We aim

This paper presents a method for mathematical modelling of surfaces conditioned on empirical data. It is based on solving a discrete biharmonic equation over a domain with given inner point and inner curve data. The inner curve data is used to model boundary values while the inner point data is used for modeling a load vector with the goal to generate a smooth surface. The construction of boun

Probed language-based assessments, where individuals describe their states using open-ended responses analyzed with Artificial Intelligence, have shown great promise for written language. But emotions are also conveyed through spoken language which might provide further assessment power to this method. Participants (N=645) were randomly assigned to watch a video clip of a church, shopping mall, or

The problem of approximate joint eigen-decomposition of a collection of matrices arises in a number of diverse engineering and signal processing problems. This problem is usually cast as an optimization problem, and it is the main goal of this publication to provide a theoretical study of the corresponding objective-functional. As our main result, we prove that this functional tends to infinity in

This study evaluated the psychometric properties of the Swedish version of the Behavior Rating Inventory of Executive Function – Second Edition (BRIEF2) across self-, parent-, and teacher-report forms in a gender- and age-balanced community sample of Swedish youth. We examined factor structure, internal consistency, inter-rater reliability, measurement invariance, and age- and gender-related diffe

A search for heavy right-handed Majorana neutrinos is performed with the ATLAS detector at the CERN Large Hadron Collider, using the (Formula Presented) of proton-proton collision data at (Formula Presented) collected during Run 2. This search targets (Formula Presented) production, in which both top quarks decay into a bottom quark and a (Formula Presented) boson, where one of the (Formula Presen

High-energy nuclear collisions create a quark-gluon plasma, whose initial condition and subsequent expansion vary from event to event, impacting the distribution of the eventwise average transverse momentum [(Formula presented)]. Disentangling the contributions from fluctuations in the nuclear overlap size (geometrical component) and other sources at a fixed size (intrinsic component) remains a ch