Simultaneous Unbinned Differential Cross-Section Measurement of Twenty-Four Z+jets Kinematic Observables with the ATLAS Detector.

Z boson events at the Large Hadron Collider can be selected with high purity and are sensitive to a diverse range of QCD phenomena. As a result, these events are often used to probe the nature of the strong force, improve Monte Carlo event generators, and search for deviations from standard model predictions. All previous measurements of Z boson production characterize the event properties using a small number of observables and present the results as differential cross sections in predetermined bins.

Disentangling Sources of Momentum Fluctuations in Xe+Xe and Pb+Pb Collisions with the ATLAS Detector.

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 [P([p_{T}])]. Disentangling the contributions from fluctuations in the nuclear overlap size (geometrical component) and other sources at a fixed size (intrinsic component) remains a challenge. This problem is addressed by measuring the mean, variance, and skewness of P([p_{T}]) in ^{208}Pb+^{208}Pb and ^{129}Xe+^{129}Xe collisions at sqrt[s_{NN}]=5.

Search for the Exclusive W Boson Hadronic Decays W^{±}→π^{±}γ, W^{±}→K^{±}γ and W^{±}→ρ^{±}γ with the ATLAS Detector.

A search for the exclusive hadronic decays W^{±}→π^{±}γ, W^{±}→K^{±}γ, and W^{±}→ρ^{±}γ is performed using up to 140  fb^{-1} of proton-proton collisions recorded with the ATLAS detector at a center-of-mass energy of sqrt[s]=13  TeV. If observed, these rare processes would provide a unique test bench for the quantum chromodynamics factorization formalism used to calculate cross sections at colliders. Additionally, at future colliders, these decays could offer a new way to measure the W boson mass through fully reconstructed decay products.

Combination of Searches for Higgs Boson Pair Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector.

This Letter presents results from a combination of searches for Higgs boson pair production using 126-140  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV recorded with the ATLAS detector. At 95% confidence level (CL), the upper limit on the production rate is 2.9 times the standard model (SM) prediction, with an expected limit of 2.

Studies of the Energy Dependence of Diboson Polarization Fractions and the Radiation-Amplitude-Zero Effect in WZ Production with the ATLAS Detector.

This Letter presents the first study of the energy dependence of diboson polarization fractions in WZ→ℓνℓ^{'}ℓ^{'}(ℓ,ℓ^{'}=e,μ) production. The dataset used corresponds to an integrated luminosity of 140  fb^{-1} of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector. Two fiducial regions with an enhanced presence of events featuring two longitudinally polarized bosons are defined.

Statistical Combination of ATLAS Run 2 Searches for Charginos and Neutralinos at the LHC.

Statistical combinations of searches for charginos and neutralinos using various decay channels are performed using 139  fb^{-1} of pp collision data at sqrt[s]=13  TeV with the ATLAS detector at the Large Hadron Collider. Searches targeting pure-wino chargino pair production, pure-wino chargino-neutralino production, or Higgsino production decaying via standard model W, Z, or h bosons are combined to extend the mass reach to the produced supersymmetric particles by 30-100 GeV. The depth of the sensitivity of the original searches is also improved by the combinations, lowering the 95% C.

First Measurement of ν_{e} and ν_{μ} Interaction Cross Sections at the LHC with FASER's Emulsion Detector.

The first results of the study of high-energy electron neutrino (ν_{e}) and muon neutrino (ν_{μ}) charged-current interactions in the FASERν emulsion-tungsten detector of the FASER experiment at the LHC are presented. A 128.8 kg subset of the FASERν volume was analyzed after exposure to 9.

Combination of Searches for Resonant Higgs Boson Pair Production Using pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector.

A combination of searches for a new resonance decaying into a Higgs boson pair is presented, using up to 139  fb^{-1} of pp collision data at sqrt[s]=13  TeV recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: bb[over ¯]bb[over ¯], bb[over ¯]τ^{+}τ^{-}, and bb[over ¯]γγ. No excess above the expected Standard Model background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV-5 TeV.

Search for Nearly Mass-Degenerate Higgsinos Using Low-Momentum Mildly Displaced Tracks in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector.

Higgsinos with masses near the electroweak scale can solve the hierarchy problem and provide a dark matter candidate, while detecting them at the LHC remains challenging if their mass splitting is O(1  GeV). This Letter presents a novel search for nearly mass-degenerate Higgsinos in events with an energetic jet, missing transverse momentum, and a low-momentum track with a significant transverse impact parameter using 140  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV collected by the ATLAS experiment. For the first time since LEP, a range of mass splittings between the lightest charged and neutral Higgsinos from 0.

Azimuthal Angle Correlations of Muons Produced via Heavy-Flavor Decays in 5.02 TeV Pb+Pb and pp Collisions with the ATLAS Detector.

Angular correlations between heavy quarks provide a unique probe of the quark-gluon plasma created in ultrarelativistic heavy-ion collisions. Results are presented of a measurement of the azimuthal angle correlations between muons originating from semileptonic decays of heavy quarks produced in 5.02 TeV Pb+Pb and pp collisions at the LHC.

Study of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector.

This Letter presents the first study of Higgs boson production in association with a vector boson (V=W or Z) in the fully hadronic qqbb final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at sqrt[s]=13  TeV and corresponding to an integrated luminosity of 137  fb^{-1}. The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b-tagging properties are used to identify jets consistent with Higgs bosons decaying into bb[over ¯].

Measurement of the Centrality Dependence of the Dijet Yield in p+Pb Collisions at sqrt[s_{NN}]=8.16 TeV with the ATLAS Detector.

ATLAS measured the centrality dependence of the dijet yield using 165  nb^{-1} of p+Pb data collected at sqrt[s_{NN}]=8.16  TeV in 2016. The event centrality, which reflects the p+Pb impact parameter, is characterized by the total transverse energy registered in the Pb-going side of the forward calorimeter.

Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC.

The first evidence for the Higgs boson decay to a Z boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018.

Combined Measurement of the Higgs Boson Mass from the H→γγ and H→ZZ^{*}→4ℓ Decay Channels with the ATLAS Detector Using sqrt[s]=7, 8, and 13 TeV pp Collision Data.

A measurement of the mass of the Higgs boson combining the H→ZZ^{*}→4ℓ and H→γγ decay channels is presented. The result is based on 140  fb^{-1} of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11±0.

First Direct Observation of Collider Neutrinos with FASER at the LHC.

We report the first direct observation of neutrino interactions at a particle collider experiment. Neutrino candidate events are identified in a 13.6 TeV center-of-mass energy pp collision dataset of 35.

Functional Loss of Terminal Complement Complex Protects Rabbits from Injury-Induced Osteoarthritis on Structural and Cellular Level.

The terminal complement complex (TCC) has been described as a potential driver in the pathogenesis of posttraumatic osteoarthritis (PTOA). However, sublytic TCC deposition might also play a crucial role in bone development and regeneration. Therefore, we elucidated the effects of TCC on joint-related tissues using a rabbit PTOA model.

Two successive cesarean deliveries through separate posterior and anterior hysterotomy due to asymptomatic uterine torsion. A case report.

Uterine torsion during pregnancy is a rare obstetrical complication that can be life-threatening for both mother and child. Although torsion usually presents with acute, non-specific symptoms, it can also occur without any symptoms and pose no immediate health threat. Ultimately, the diagnosis of torsion is often made only during cesarean section.

Hypothermia Promotes Cell-Protective and Chondroprotective Effects After Blunt Cartilage Trauma.

Background: Cryotherapy is routinely administered after sports injuries of synovial joints. Although positive clinical effects on periarticular swelling and pain have been described, the effects on the cell biological activities of cartilage and synovial cells remain largely unknown so far.

Hypothesis: Local hypothermia alleviates synovial reactions and prevents chondrocyte death as well as cartilage destructive processes after blunt cartilage trauma.

Striking a new path in reducing cartilage breakdown: combination of antioxidative therapy and chondroanabolic stimulation after blunt cartilage trauma.

Cartilage injury can trigger crucial pathomechanisms, including excessive cell death and expression of matrix-destructive enzymes, which contribute to the progression of a post-traumatic osteoarthritis (PTOA). With the intent to create a novel treatment strategy for alleviating trauma-induced cartilage damage, we complemented a promising antioxidative approach based on cell and chondroprotective N-acetyl cysteine (NAC) by chondroanabolic stimulation. Overall, three potential pro-anabolic growth factors - IGF-1, BMP7 and FGF18 - were tested comparatively with and without NAC in an ex vivo human cartilage trauma-model.

Friction properties of a new silk fibroin scaffold for meniscal replacement.

The menisci protect the articular cartilage by reducing contact pressure in the knee. To restore their function after injury, a new silk fibroin replacement scaffold was developed. To elucidate its tribological properties, friction of the implant was tested against cartilage and glass, where the latter is typically used in tribological cartilage studies.

Antioxidative therapy in an ex vivo human cartilage trauma-model: attenuation of trauma-induced cell loss and ECM-destructive enzymes by N-acetyl cysteine.

Objective: Mechanical trauma of articular cartilage results in cell loss and cytokine-driven inflammatory response. Subsequent accumulation of reactive oxygen (ROS) and nitrogen (RNS) species enhances the enzymatic degradation of the extracellular matrix (ECM). This study aims on the therapeutic potential of N-acetyl cysteine (NAC) in a human ex vivo cartilage trauma-model, focusing on cell- and chondroprotective features.