Prospects for collider searches for dark matter with heavy quarks

We present projections for future collider searches for dark matter produced in association with bottom or top quarks. Such production channels give rise to final states with missing transverse energy and one or more b-jets. Limits are given assuming an effective scalar operator coupling dark matter to quarks, where the dedicated analysis discussed here improves significantly over a generic monojet analysis. We give updated results for an anticipated high-luminosity LHC run at 14 TeV and for a 33 TeV hadron collider

Searches for new phenomena in leptonic final states using the ATLAS detector

Many theories beyond the Standard Model predict new phenomena which decay to well isolated, high-pt leptons. Searches for new physics models with these signatures are performed using the ATLAS experiment at the LHC. The results reported here use the pp collision data sample collected in 2015 and 2016 by the ATLAS detector at the LHC with a centre-of-mass energy of 13 TeV

Cardiovascular risk factors, anxiety symptoms and inflammation markers: Evidence of association from a cross-sectional study

Introduction Anxiety disorders and Cardiovascular (CV) diseases, among the most common disorders in Western World, are often comorbid. A chronic systemic inflammatory state might be a shared underlining pathophysiological mechanism. Aims To investigate the association between anxiety symptoms, CV risks factors and inflammatory markers in an outpatient sample. Methods Cross-sectional study. Inclusion criteria: outpatients aged ≥40 years, attending colonoscopy after positive faecal occult blood test, negative medical history for cancer. Collected data: blood pressure, glycaemia, lipid profile, waist circumference, BMI, PCR (C Reactive Protein), LPS (bacterial Lipopolysaccharide). Psychometric tests: HADS, TCI, IMSA, SF36. Statistical analysis performed with STATA13. Results Fifty four patients enrolled (27 males, 27 females). Sixteen patients (30.19%) were positive for anxiety symptoms. Thirty-three patients (61.11%) had hypertension, 14 (25.93%) hyperglycaemia and 64.81% were overweight, with frank obesity (BMI≥ 30) in 11 subjects (20.37%). Anxiety symptoms were associated with low hematic HDL values (OR = 0.01; P = 0.01) and high concentration of triglycerides (OR = 0.023; P = 0.02) at the multiple regression model. At the univariate logistic analysis, anxiety was associated with LPS (OR = 1.06; P = 0.04). Conclusions Further evidence over the epidemiological link between common mental disorders and CV diseases was collected, with possible hints on pathophysiology and causative mechanisms related to inflammation. The importance of screening for anxiety and depression in medical populations is confirmed. Suggestions on future availability of screening tools based on inflammatory-related indicators should be the focus of future research

Search for resonant WZ production in the fully leptonic final state in proton–proton collisions at √s=13 TeV with the ATLAS detector

A search for a WZ resonance, in the fully leptonic final state (electrons or muons), is performed using 139 fb - 1 of data collected at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The results are interpreted in terms of a singly charged Higgs boson of the Georgi–Machacek model, produced by WZ fusion, and of a Heavy Vector Triplet, with the resonance produced by WZ fusion or the Drell–Yan process. No significant excess over the Standard Model prediction is observed and limits are set on the production cross-section times branching ratio as a function of the resonance mass for these processes

Measurements of W+W- production in decay topologies inspired by searches for electroweak supersymmetry

This paper presents a measurement of fiducial and differential cross-sections for W+W- production in proton–proton collisions at s=13 TeV with the ATLAS experiment at the Large Hadron Collider using a dataset corresponding to an integrated luminosity of 139 fb - 1 . Events with exactly one electron, one muon and no hadronic jets are studied. The fiducial region in which the measurements are performed is inspired by searches for the electroweak production of supersymmetric charginos decaying to two-lepton final states. The selected events have moderate values of missing transverse momentum and the ‘stransverse mass’ variable mT2 , which is widely used in searches for supersymmetry at the LHC. The ranges of these variables are chosen so that the acceptance is enhanced for direct W+W- production and suppressed for production via top quarks, which is treated as a background. The fiducial cross-section and particle-level differential cross-sections for six variables are measured and compared with two theoretical SM predictions from perturbative QCD calculations

Observation of the γγ→ττ process in Pb+Pb collisions and constraints on the τ-lepton anomalous magnetic moment with the ATLAS detector

This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment a_{τ}. The dataset corresponds to an integrated luminosity of 1.44 nb^{-1} of LHC Pb+Pb collisions at sqrt[s_{NN}]=5.02 TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ_{ττ}=1.03_{-0.05}^{+0.06} assuming the standard model value for a_{τ}. To measure a_{τ}, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a_{τ} is -0.057<0.024

Charged-hadron production in pp, p+Pb, Pb+Pb, and Xe+Xe collisions at √sNN = 5 TeV with the ATLAS detector at the LHC

This paper presents measurements of charged-hadron spectra obtained in pp, p+Pb, and Pb+Pb collisions at s or sNN = 5.02 TeV, and in Xe+Xe collisions at sNN = 5.44 TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb −1, 28 nb −1, 0.50 nb −1, and 3 μb −1, respectively. The nuclear modification factors RpPb and R AA are obtained by comparing the spectra in heavy-ion and pp collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor RpPb shows a moderate enhancement above unity with a maximum at p T ≈ 3 GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct p T-dependence with a local maximum at p T ≈ 2 GeV and a local minimum at p T ≈ 7 GeV. This dependence is more distinguishable in more central collisions. No significant |η|-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe R AA better in central collisions and in the p T range from about 10 to 100 GeV. [Figure not available: see fulltext.