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 ¯]. Dominant backgrounds from multijet production are determined directly from the data, and a likelihood fit to the jet mass distribution of Higgs boson candidates is used to extract the number of signal events. The VH production cross section is measured inclusively and differentially in several ranges of Higgs boson transverse momentum: 250-450, 450-650, and greater than 650 GeV. The inclusive signal yield relative to the standard model expectation is observed to be μ=1.4_{-0.9}^{+1.0} and the corresponding cross section is 3.1±1.3(stat)_{-1.4}^{+1.8}(syst)  pb.

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. The central-to-peripheral ratio of the scaled dijet yields, R_{CP}, is evaluated, and the results are presented as a function of variables that reflect the kinematics of the initial hard parton scattering process. The R_{CP} shows a scaling with the Bjorken x of the parton originating from the proton, x_{p}, while no such trend is observed as a function of x_{Pb}. This analysis provides unique input to understanding the role of small proton spatial configurations in p+Pb collisions by covering parton momentum fractions from the valence region down to x_{p}∼10^{-3} and x_{Pb}∼4×10^{-4}.

Search for New Phenomena in Two-Body Invariant Mass Distributions Using Unsupervised Machine Learning for Anomaly Detection at sqrt[s]=13 TeV with the ATLAS Detector

Searches for new resonances are performed using an unsupervised anomaly-detection technique. Events with at least one electron or muon are selected from 140  fb^{-1} of pp collisions at sqrt[s]=13  TeV recorded by ATLAS at the Large Hadron Collider. The approach involves training an autoencoder on data, and subsequently defining anomalous regions based on the reconstruction loss of the decoder. Studies focus on nine invariant mass spectra that contain pairs of objects consisting of one light jet or b jet and either one lepton (e,μ), photon, or second light jet or b jet in the anomalous regions. No significant deviations from the background hypotheses are observed. Limits on contributions from generic Gaussian signals with various widths of the resonance mass are obtained for nine invariant masses in the anomalous regions.

Clinical implication of the patient's disease awareness and adherence to medications in patients undergoing atrial fibrillation ablation

Background

The effects of the patient's disease awareness on the management of postablation of atrial fibrillation (AF) are unknown.

Methods

One hundred thirty-three AF patients undergoing an initial ablation were given a disease awareness questionnaire with a score of 16 points (8 points about AF in general and 8 points about oral anticoagulants) for the Jessa Atrial Fibrillation Knowledge Questionnaire (JAKQ) before and 1-year-after ablation. We divided them into the poor disease awareness group and good disease awareness group according to the median value (75%) of the total JAKQ score about AF in general, and compared the baseline patient characteristics and the 1-year changes in the JAKQ score, medication adherence, blood pressure, laboratory data, echocardiographic parameters, and AF/atrial tachycardia (AT) recurrence rate between the two groups.

Results

Forty-two (31.6%) patients were classified as having poor disease awareness (<75% of the total JAKQ score), which was closely associated with poor medication adherence, hypertension, diabetes, dyslipidemia, and greater left atrial volume (LAV). These trends in the poor disease awareness group remained unchanged 1 year after the ablation. During the 25.3-month follow-up, the AF/AT recurrence rate was significantly higher in the poor disease awareness than the good disease awareness group (23.8% vs. 7.7%; p = .003 by the log-rank test).

Conclusions

Poor disease awareness was linked to poor medication adherence, lifestyle-related diseases, and greater LAV before and even 1 year after the ablation, making it a potential surrogate marker for AF/AT recurrence. These findings highlight the clinical significance of disease awareness in AF management.

Observation of WZγ Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter reports the observation of WZγ production and a measurement of its cross section using 140.1±1.2  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The WZγ production cross section, with both the W and Z bosons decaying leptonically, pp→WZγ→ℓ^{'}^{±}νℓ^{+}ℓ^{-}γ (ℓ^{(^{'})}=e, μ), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross section is found to be 2.01±0.30(stat)±0.16(syst)  fb. The corresponding standard model predicted cross section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50±0.06  fb. The observed significance of the WZγ signal is 6.3σ, compared with an expected significance of 5.0σ.

Characteristics of tissue temperature during ablation with THERMOCOOL SMARTTOUCH SF versus TactiCath versus QDOT MICRO catheters (Qmode and Qmode+): An in vivo porcine study

INTRODUCTION

High-power short-duration (HPSD) ablation at 50 W, guided by ablation index (AI) or lesion size index (LSI), and a 90 W/4 s very HSPD (vHPSD) setting are available for atrial fibrillation (AF) treatment. Yet, tissue temperatures during ablation with different catheters around venoatrial junction and collateral tissues remain unclear.

METHODS

In this porcine study, we surgically implanted thermocouples on the epicardium near the superior vena cava (SVC), right pulmonary vein, and esophagus close to the inferior vena cava. We then compared tissue temperatures during 50W-HPSD guided by AI 400 or LSI 5.0, and 90 W/4 s-vHPSD ablation using THERMOCOOL SMARTTOUCH SF (STSF), TactiCath ablation catheter, sensor enabled (TacthCath), and QDOT MICRO (Qmode and Qmode+ settings) catheters.

RESULTS

STSF produced the highest maximum tissue temperature (Tmax ), followed by TactiCath, and QDOT MICRO in Qmode and Qmode+ (62.7 ± 12.5°C, 58.0 ± 10.1°C, 50.0 ± 12.1°C, and 49.2 ± 8.4°C, respectively; p = .005), achieving effective transmural lesions. Time to lethal tissue temperature ≥50°C (t-T ≥ 50°C) was fastest in Qmode+, followed by TacthCath, STSF, and Qmode (4.3 ± 2.5, 6.4 ± 1.9, 7.1 ± 2.8, and 7.7 ± 3.1 s, respectively; p < .001). The catheter tip-to-thermocouple distance for lethal temperature (indicating lesion depth) from receiver operating characteristic curve analysis was deepest in STSF at 5.2 mm, followed by Qmode at 4.3 mm, Qmode+ at 3.1 mm, and TactiCath at 2.8 mm. Ablation at the SVC near the phrenic nerve led to sudden injury at t-T ≥ 50°C in all four settings. The esophageal adventitia injury was least deep with Qmode+ ablation (0.4 ± 0.1 vs. 0.8 ± 0.4 mm for Qmode, 0.9 ± 0.3 mm for TactiCath, and 1.1 ± 0.5 mm for STSF, respectively; p = .005), correlating with Tmax .

CONCLUSION

This study revealed distinct tissue temperature patterns during HSPD and vHPSD ablations with the three catheters, affecting lesion effectiveness and collateral damage based on Tmax and/or t-T ≥ 50°C. These findings provide key insights into the safety and efficacy of AF ablation with these four settings.

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±0.09(stat)±0.06(syst)=125.11±0.11  GeV. This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics.

Search for Dark Photons in Rare Z Boson Decays with the ATLAS Detector

A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the standard model Z boson is presented, using 139  fb^{-1} of sqrt[s]=13  TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon's coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α_{D}ϵ^{2}, in the dark photon mass range of [5, 40] GeV except for the ϒ mass window [8.8, 11.1] GeV. This search explores new parameter space not previously excluded by other experiments.

Observation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector

This Letter reports the observation of single top quarks produced together with a photon, which directly probes the electroweak coupling of the top quark. The analysis uses 139  fb^{-1} of 13 TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. Requiring a photon with transverse momentum larger than 20 GeV and within the detector acceptance, the fiducial cross section is measured to be 688±23(stat) _{-71}^{+75}(syst)  fb, to be compared with the standard model prediction of 515_{-42}^{+36}  fb at next-to-leading order in QCD.

Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at sqrt[s_{NN}]=5.02 TeV with the ATLAS Detector

This letter presents a measurement of the nuclear modification factor of large-radius jets in sqrt[s_{NN}]=5.02  TeV Pb+Pb collisions by the ATLAS experiment. The measurement is performed using 1.72  nb^{-1} and 257  pb^{-1} of Pb+Pb and pp data, respectively. The large-radius jets are reconstructed with the anti-k_{t} algorithm using a radius parameter of R=1.0, by reclustering anti-k_{t} R=0.2 jets, and are measured over the transverse momentum (p_{T}) kinematic range of 158 Collapse

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Measurement of the Sensitivity of Two-Particle Correlations in pp Collisions to the Presence of Hard Scatterings

A key open question in the study of multiparticle production in high-energy pp collisions is the relationship between the "ridge"-i.e., the observed azimuthal correlations between particles in the underlying event that extend over all rapidities-and hard or semihard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the underlying event. To address this question, two-particle correlations are measured in pp collisions at sqrt[s]=13  TeV using data collected by the ATLAS experiment at the LHC, with an integrated luminosity of 15.8  pb^{-1}, in two different configurations. In the first case, charged particles associated with jets are excluded from the correlation analysis, while in the second case, correlations are measured between particles within jets and charged particles from the underlying event. Second-order flow coefficients, v_{2}, are presented as a function of event multiplicity and transverse momentum. These measurements show that excluding particles associated with jets does not affect the measured correlations. Moreover, particles associated with jets do not exhibit any significant azimuthal correlations with the underlying event, ruling out hard processes contributing to the ridge.

Observation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector

A search is made for potential ccc[over ¯]c[over ¯] tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at sqrt[s]=13  TeV, corresponding to an integrated luminosity of 140  fb^{-1} recorded by the ATLAS experiment at LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, are studied. Backgrounds are estimated based on a hybrid approach involving Monte Carlo simulations and data-driven methods. Statistically significant excesses with respect to backgrounds dominated by the single parton scattering are seen in the di-J/ψ channel consistent with a narrow resonance at 6.9 GeV and a broader structure at lower mass. A statistically significant excess is also seen in the J/ψ+ψ(2S) channel. The fitted masses and decay widths of the structures are reported.

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 Collapse

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Strong Constraints on Jet Quenching in Centrality-Dependent p+Pb Collisions at 5.02 TeV from ATLAS

Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including pp and p+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36  nb^{-1} of p+Pb and 3.6  pb^{-1} of pp collisions at 5.02 TeV. The yields of charged hadrons with p_{T}^{ch}>0.5  GeV near and opposite in azimuth to jets with p_{T}^{jet}>30 or 60 GeV, and the ratios of these yields between p+Pb and pp collisions, I_{pPb}, are reported. The collision centrality of p+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The I_{pPb} values are consistent with unity within a few percent for hadrons with p_{T}^{ch}>4  GeV at all centralities. These data provide new, strong constraints that preclude almost any parton energy loss in central p+Pb collisions.

Search for Heavy Neutral Leptons in Decays of W Bosons Using a Dilepton Displaced Vertex in sqrt[s]=13 TeV pp Collisions with the ATLAS Detector

A search for a long-lived, heavy neutral lepton (N) in 139  fb^{-1} of sqrt[s]=13  TeV pp collision data collected by the ATLAS detector at the Large Hadron Collider is reported. The N is produced via W→Nμ or W→Ne and decays into two charged leptons and a neutrino, forming a displaced vertex. The N mass is used to discriminate between signal and background. No signal is observed, and limits are set on the squared mixing parameters of the N with the left-handed neutrino states for the N mass range 3  GeV Collapse

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Test of CP Invariance in Higgs Boson Vector-Boson-Fusion Production Using the H→γγ Channel with the ATLAS Detector

A test of CP invariance in Higgs boson production via vector-boson fusion has been performed in the H→γγ channel using 139  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV collected by the ATLAS detector at the LHC. The optimal observable method is used to probe the CP structure of interactions between the Higgs boson and electroweak gauge bosons, as described by an effective field theory. No sign of CP violation is observed in the data. Constraints are set on the parameters describing the strength of the CP-odd component in the coupling between the Higgs boson and the electroweak gauge bosons in two effective field theory bases: d[over ˜] in the HISZ basis and c_{HW[over ˜]} in the Warsaw basis. The results presented are the most stringent constraints on CP violation in the coupling between Higgs and weak bosons. The 95% C.L. constraint on d[over ˜] is derived for the first time and the 95% C.L. constraint on c_{HW[over ˜]} has been improved by a factor of 5 compared to the previous measurement.

Trends over the recent 6 years in ablation modalities and strategies, post-ablation medication, and clinical outcomes of atrial fibrillation ablation

Background

Ablation strategies and modalities for atrial fibrillation (AF) have transitioned over the past decade, but their impact on post-ablation medication and clinical outcomes remains to be fully investigated.

Methods

We divided 682 patients who had undergone AF ablation in 2014-2019 (420 paroxysmal AFs [PAF], 262 persistent AFs [PerAF]) into three groups according to the period, that is, the 2014-2015 (n = 139), 2016-2017 (n = 244), and 2018-2019 groups (n = 299), respectively.

Results

Persistent AF became more prevalent and the left atrial (LA) diameter larger over the 6 years. Extra-pulmonary vein (PV)-LA ablation was more frequently performed in the 2014-2015 group than in the 2016-2017 and 2018-2019 groups (41.1% vs. 9.1% and 8.1%; p < .001). The 2-year freedom rate from AF/atrial tachycardias for PAF was similar among the three groups (84.0% vs. 83.1% vs. 86.7%; p = .98) but lowest in the 2014-2015 group for PerAF (63.9% vs. 82.7% and 86.3%; p = .025) despite the highest post-ablation antiarrhythmic drug use. Cardiac tamponade was significantly decreased in the 2018-2019 group (3.6% vs. 2.0% vs. 0.33%; p = 0.021). There was no difference in the 2-year clinically relevant events among the three groups.

Conclusion

Although ablation was performed in a more diseased LA and extra-PV-LA ablation was less frequent in recent years, the complication rate decreased, and AF recurrences for PAF remained unchanged, but that for PerAF decreased. Clinically relevant events remained unchanged over the recent 6 years, suggesting that the impact of the recent ablation modalities and strategies on remote clinically relevant events may be small during this study period.

Dielectric Relaxation by Quantum Critical Magnons

We report the experimental observation of dielectric relaxation by quantum critical magnons. Complex capacitance measurements reveal a dissipative feature with a temperature-dependent amplitude due to low-energy lattice excitations and an activation behavior of the relaxation time. The activation energy softens close to a field-tuned magnetic quantum critical point at H=H_{c} and follows single-magnon energy for H>H_{c}, showing its magnetic origin. Our study demonstrates the electrical activity of coupled low-energy spin and lattice excitations, an example of quantum multiferroic behavior.

Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νββ) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>2.3×10^{26}  yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations.

In vivo tissue temperatures during 90 W/4 sec-very high power-short-duration (vHPSD) ablation versus ablation index-guided 50 W-HPSD ablation: A porcine study

INTRODUCTION

Neither the actual in vivo tissue temperatures reached with 90 W/4 s-very high-power short-duration (vHPSD) ablation for atrial fibrillation nor the safety and efficacy profile have been fully elucidated.

METHODS

We conducted a porcine study (n = 15) in which, after right thoracotomy, we implanted 6-8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We compared tissue temperatures close to a QDOT MICRO catheter, between during 90 W/4 s-vHPSD ablation during ablation index (AI: target 400)-guided 50 W-HPSD ablation, both targeting a contact force of 8-15 g.

RESULTS

Maximum tissue temperature reached during 90 W/4 s-vHPSD ablation did not differ significantly from that during 50 W-HPSD ablation (49.2 ± 8.4°C vs. 50.0 ± 12.1°C; p = .69) and correlated inversely with distance between the catheter tip and the thermocouple, regardless of the power settings (r = -0.52 and r = -0.37). Lethal temperature (≥50°C) was best predicted at a catheter tip-to-thermocouple distance cut-point of 3.13 and 4.27 mm, respectively. All lesions produced by 90 W/4 s-vHPSD or 50 W-HPSD ablation were transmural. Although there was no difference in the esophageal injury rate (50% vs. 66%, p = .80), the thermal lesion was significantly shallower with 90 W/4 s-vHPSD ablation than with 50W-HPSD ablation (381.3 ± 127.3 vs. 820.0 ± 426.1 μm from the esophageal adventitia; p = .039).

CONCLUSION

Actual tissue temperatures reached with 90 W/4 s-vHPSD ablation appear similar to those with AI-guided 50 W-HPSD ablation, with the distance between the catheter tip and target tissue being shorter for the former. Although both ablation settings may create transmural lesions in thin atrial tissues, any resulting esophageal thermal lesions appear shallower with 90 W/4 s-vHPSD ablation.

In vivo tissue temperature during lesion size index-guided 50W ablation versus 30W ablation: A porcine study

BACKGROUND

Neither the actual in vivo tissue temperatures reached with lesion size index (LSI)-guided high-power short-duration (HPSD) ablation for atrial fibrillation nor the safety profile has been elucidated.

METHODS

We conducted a porcine study (n = 7) in which, after right thoracotomy, we implanted 6-8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We compared tissue temperatures reached during 50 W-HPSD ablation with those reached during standard (30 W) ablation, both targeting an LSI of 5.0 (5-15 g contact force).

RESULTS

T_max  (maximum tissue temperature when the thermocouple was located ≤5 mm from the catheter tip) reached during HPSD ablation was modestly higher than that reached during standard ablation (58.0 ± 10.1°C vs. 53.6 ± 9.2°C; p = .14) and peak tissue temperature correlated inversely with the distance between the catheter tip and the thermocouple, regardless of the power settings (HPSD: r = -0.63; standard: r = -0.66). Lethal temperature (≥50°C) reached 6.3 ± 1.8 s and 16.9 ± 16.1 s after the start of HPSD and standard ablation, respectively (p = .002), and it was best predicted at a catheter tip-to-thermocouple distance cut point of 2.8 and 5.3 mm, respectively. All lesions produced by HPSD ablation and by standard ablation were transmural. There was no difference between HPSD ablation and standard ablation in the esophageal injury rate (70% vs. 75%, p = .81), but the maximum distance from the esophageal adventitia to the injury site tended to be shorter (0.94 ± 0.29 mm vs. 1.40 ± 0.57 mm, respectively; p = .09).

CONCLUSIONS

Actual tissue temperatures reached with LSI-guided HPSD ablation appear to be modestly higher, with a shorter distance between the catheter tip and thermocouple achieving lethal temperature, than those reached with standard ablation. HPSD ablation lasting <6 s may help minimize lethal thermal injury to the esophagus lying at a close distance.

Observation of WWW Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter reports the observation of WWW production and a measurement of its cross section using 139  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from WWW production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive WWW production cross section is measured to be 820±100 (stat)±80 (syst)  fb, approximately 2.6 standard deviations from the predicted cross section of 511±18  fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy.

A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

The standard model of particle physics1-4 describes the known fundamental particles and forces that make up our Universe, with the exception of gravity. One of the central features of the standard model is a field that permeates all of space and interacts with fundamental particles5-9. The quantum excitation of this field, known as the Higgs field, manifests itself as the Higgs boson, the only fundamental particle with no spin. In 2012, a particle with properties consistent with the Higgs boson of the standard model was observed by the ATLAS and CMS experiments at the Large Hadron Collider at CERN10,11. Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, enabling much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and W and Z bosons-the carriers of the strong, electromagnetic and weak forces-are studied in detail. Interactions with three third-generation matter particles (bottom (b) and top (t) quarks, and tau leptons (τ)) are well measured and indications of interactions with a second-generation particle (muons, μ) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the standard model.

Search for Lepton-Flavor Violation in Z-Boson Decays with τ Leptons with the ATLAS Detector

A search for lepton-flavor-violating Z→eτ and Z→μτ decays with pp collision data recorded by the ATLAS detector at the LHC is presented. This analysis uses 139  fb^{-1} of Run 2 pp collisions at sqrt[s]=13  TeV and is combined with the results of a similar ATLAS search in the final state in which the τ lepton decays hadronically, using the same data set as well as Run 1 data. The addition of leptonically decaying τ leptons significantly improves the sensitivity reach for Z→ℓτ decays. The Z→ℓτ branching fractions are constrained in this analysis to B(Z→eτ)<7.0×10^{-6} and B(Z→μτ)<7.2×10^{-6} at 95% confidence level. The combination with the previously published analyses sets the strongest constraints to date: B(Z→eτ)<5.0×10^{-6} and B(Z→μτ)<6.5×10^{-6} at 95% confidence level.

Denosumab-related osteonecrosis of the jaw after tooth extraction and the effects of a short drug holiday in cancer patients: a multicenter retrospective study

Pre-existing inflammation, corticosteroid therapy, periapical periodontitis, longer duration of denosumab therapy, and female sex were significantly associated with an increased risk of denosumab-related osteonecrosis of the jaw after tooth extraction in patients with cancer on oncologic doses of denosumab. A short drug holiday did not protect against this complication.

INTRODUCTION

This study retrospectively investigated the relationship between various risk factors, including brief discontinuation of denosumab, and development of denosumab-related osteonecrosis of the jaw (DRONJ) after tooth extraction in patients with cancer who were receiving oncologic doses of this agent.

METHODS

Data were collected on demographic characteristics, duration of denosumab therapy, whether or not denosumab was discontinued before tooth extraction (drug holiday), duration of discontinuation, presence of pre-existing inflammation, and whether or not additional surgical procedures were performed. Risk factors for DRONJ after tooth extraction were evaluated by univariate and multivariate analyses.

RESULTS

A total of 136 dental extractions were performed in 72 patients (31 men, 41 women) with cancer who were receiving oncologic doses of denosumab. Post-extraction DRONJ was diagnosed in 39 teeth (28.7%) in 25 patients. Tooth extraction was significantly associated with development of DRONJ only in patients with pre-existing inflammation (odds ratio [OR] 243.77), those on corticosteroid therapy (OR 73.50), those with periapical periodontitis (OR 14.13), those who had been taking oncologic doses of denosumab for a longer period (OR 4.69), and in women (OR 1.04). There was no significant difference in the occurrence of DRONJ between patients who had a drug holiday before tooth extraction and those who did not.

CONCLUSIONS

These findings suggest that inflamed teeth should be extracted immediately in patients with cancer who are receiving oncologic doses of denosumab. Drug holidays have no significant impact on the risk of DRONJ.

Actual tissue temperature during ablation index-guided high-power short-duration ablation versus standard ablation: Implications in terms of the efficacy and safety of atrial fibrillation ablation

BACKGROUND

Actual in vivo tissue temperatures and the safety profile during high-power short-duration (HPSD) ablation of atrial fibrillation have not been clarified.

METHODS

We conducted an animal study in which, after a right thoracotomy, we implanted 6-8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We recorded tissue temperatures during a 50 W-HPSD ablation and 30 W-standard ablation targeting an ablation index (AI) of 400 (5-15 g contact force).

RESULTS

Maximum tissue temperatures reached with HSPD ablation were significantly higher than that reached with standard ablation (62.7 ± 12.5 vs. 52.7 ± 11.4°C, p = 0.033) and correlated inversely with the distance between the catheter tip and thermocouple, regardless of the power settings (HPSD: r = -0.71; standard: r = -0.64). Achievement of lethal temperatures (≥50°C) was within 7.6 ± 3.6 and 12.1 ± 4.1 s after HPSD and standard ablation, respectively (p = 0.003), and was best predicted at cutoff points of 5.2 and 4.4 mm, respectively. All HPSD ablation lesions were transmural, but 19.2% of the standard ablation lesions were not (p = 0.011). There was no difference between HPSD and standard ablation regarding the esophageal injury rate (30% vs. 33.3%, p > 0.99), with the injury appearing to be related to the short distance from the catheter tip.

CONCLUSIONS

Actual tissue temperatures reached with AI-guided HPSD ablation appeared to be higher with a greater distance between the catheter tip and target tissue than those with standard ablation. HPSD ablation for <7 s may help prevent collateral tissue injury when ablating within a close distance.

Modified ablation index: a novel determinant of a successful first-pass left atrial posterior wall isolation

Although a left atrial posterior wall isolation (LAPWI) in addition to a pulmonary vein isolation is a well-accepted option for persistent atrial fibrillation (AF), a complete isolation can be challenging. This study aimed to evaluate the performance of a modified ablation index (AI) (AI/bipolar voltage along the ablation line) for predicting a durable LAPWI. The study included 55 consecutive patients, aged 65 ± 11 years, who underwent an electroanatomic mapping-guided LAPWI of AF. The association between the gaps (first-pass LAPWI failure and/or acute LAPW reconnections), voltage amplitude along the roof and floor lines, and thickness of the LAPW was investigated. Gaps occurred in 22 patients (40%) and in 26 (8%) of the 330 line segments. Gaps were associated with a relatively high bipolar voltage (3.38 ± 1.83 vs. 1.70 ± 1.12 mV, P < 0.0001) and thick LA wall (2.52 ± 1.15 vs. 1.42 ± 0.44 mm, P < 0.0001). A modified AI ≤ 199 AU/mV, bipolar voltage ≥ 2.64 mV, wall thickness ≥ 2.04 mm, and roof ablation line ≥ 43.4 mm well predicted gaps (AUCs: 0.783, 0.787, 0.858, and 0.752, respectively). A high-voltage zone, thick LAPW, and long roof ablation line appeared to be determinants of gaps, and a modified AI ≥ 199 AU/mV along the ablation lines appeared to predict an acute durable LAPWI.

Aerosol Loading and Radiation Budget Perturbations in Densely Populated and Highly Polluted Indo-Gangetic Plain by COVID-19: Influences on Cloud Properties and Air Temperature

Aerosols emitted in densely populated and industrialized Indo-Gangetic Plain, one of the most polluted regions in the world, modulate regional climate, monsoon, and Himalayan glacier retreat. Thus, this region is important for understanding aerosol perturbations and their resulting impacts on atmospheric changes during COVID-19 lockdown period, a natural experimental condition created by the pandemic. By analyzing 5 years (2016-2020) data of aerosols and performing a radiative transfer calculation, we found that columnar and near-surface aerosol loadings decreased, leading to reductions in radiative cooling at the surface and top of the atmosphere and atmospheric warming during lockdown period. Further, satellite data analyses showed increases in cloud optical thickness and cloud-particle effective radius and decrease in lower tropospheric air temperature during lockdown period. These results indicate critical influences of COVID-19 lockdown on regional climate and water cycle over Indo-Gangetic Plain, emphasizing need for further studies from modeling perspectives.

Search for New Phenomena in Final States with Two Leptons and One or No b-Tagged Jets at sqrt[s]=13 TeV Using the ATLAS Detector

A search for new phenomena is presented in final states with two leptons and one or no b-tagged jets. The event selection requires the two leptons to have opposite charge, the same flavor (electrons or muons), and a large invariant mass. The analysis is based on the full run-2 proton-proton collision dataset recorded at a center-of-mass energy of sqrt[s]=13  TeV by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 139  fb^{-1}. No significant deviation from the expected background is observed in the data. Inspired by the B-meson decay anomalies, a four-fermion contact interaction between two quarks (b, s) and two leptons (ee or μμ) is used as a benchmark signal model, which is characterized by the energy scale and coupling, Λ and g_{*}, respectively. Contact interactions with Λ/g_{*} lower than 2.0 (2.4) TeV are excluded for electrons (muons) at the 95% confidence level, still far below the value that is favored by the B-meson decay anomalies. Model-independent limits are set as a function of the minimum dilepton invariant mass, which allow the results to be reinterpreted in various signal scenarios.

Search for Displaced Leptons in sqrt[s]=13 TeV pp Collisions with the ATLAS Detector

A search for charged leptons with large impact parameters using 139  fb^{-1} of sqrt[s]=13  TeV pp collision data from the ATLAS detector at the LHC is presented, addressing a long-standing gap in coverage of possible new physics signatures. Results are consistent with the background prediction. This search provides unique sensitivity to long-lived scalar supersymmetric lepton partners (sleptons). For lifetimes of 0.1 ns, selectron, smuon, and stau masses up to 720, 680, and 340  GeV, respectively, are excluded at 95% confidence level, drastically improving on the previous best limits from LEP.

Formation of low-voltage zones on the anterior left atrial wall due to mechanical compression by the ascending aorta

BACKGROUND

Although low-voltage zones (LVZs) in the left atrium (LA) are considered arrhythmogenic substrates in some patients with atrial fibrillation (AF), the pathophysiologic factors responsible for LVZ formations remain unclear.

OBJECTIVE

To elucidate the anatomical relationship between the LA and ascending aorta responsible for anterior LA wall remodeling.

METHODS

We assessed the relationship between existence of LVZs on the anterior LA wall and the three-dimensional computed tomography image measurements in 102 patients who underwent AF ablation.

RESULTS

Twenty-nine patients (28%) had LVZs grearer than 1.0 cm² on the LA wall in the LA-ascending aorta contact area (LVZ group); no LVZs were seen in the other 73 patients (no-LVZ group). The LVZ group (vs. no-LVZ group) had a smaller aorta-LA angle (21.0 ± 7.7° vs. 24.9 ± 7.1°, p = .015), greater aorta-left-ventricle (LV) angle (131.3 ± 8.8° vs. 126.0 ± 7.9°; p = .005), greater diameter of the noncoronary cusp (NCC; 20.4 ± 2.2 vs. 19.3 ± 2.5 mm; p = .036), thinner LA wall-thickness adjacent to the NCC (2.3 ± 0.7 vs. 2.8 ± 0.8 mm; p = .006), and greater cardiothoracic ratio (percentage of the area in the thoracic area, 40.1 ± 7.1% vs. 35.4 ± 5.7%, p < .001). The aorta-LA angle correlated positively with the patients' body mass index (BMI), and the aorta-LV angle correlated negatively with the body weight and BMI.

CONCLUSION

Deviation of the ascending aorta's course and distention of the NCC appear to be related to the development of LA anterior wall LVZs in the LA-ascending aorta contact area. Mechanical pressure exerted by extracardiac structures on the LA along with the limited thoracic space may contribute to the development of LVZs associated with AF.

Three-dimensional visualization of bidirectional preferential pathway conduction of premature ventricular contractions originating from the outflow tract

INTRODUCTION

Preferential pathway conduction is mostly detected as fractionated presystolic-potentials preceding the QRS during premature ventricular contractions (PVCs) and late-potentials during sinus rhythm (SR), but the electrophysiologic mechanisms and significance of these potentials have not been fully clarified. We describe a PVC case series in which the preferential pathway conduction was three-dimensionally visualized.

METHODS

Five PVCs (two from the left coronary cusp, two from the commissure of the left and right coronary cusps, and one from the pulmonary artery) in four patients for which a fractionated presystolic-potential during the PVCs and late-potential during SR were recorded at the successful ablation site were reviewed, and three-dimensional coherent activation maps with the conduction velocity vector during the PVCs and SR were reconstructed.

RESULTS

At the successful ablation site, an "M"-shaped discrete presystolic-potential and "W"-shaped discrete late-potential were recorded in all patients. The configuration of the inverted electrogram of the presystolic-potential was similar to that of the electrogram exhibiting the late-potential. We created coherent activation maps annotating the onset of the presystolic-potentials during the PVCs and offset of the late-potentials during SR, which suggested bidirectional conduction of the preferential pathway connecting the PVC origin to the myocardium.

CONCLUSION

Detailed activation mapping of these PVCs is consistent with the presence of fibers along the aortic or pulmonic valve ring that have preferential directions for conduction. PVCs produce a presystolic-potential. In SR, the fiber is activated late and from the opposite direction, producing an inverted potential inscribed on the end of the QRS.

Search for Dark Matter Produced in Association with a Dark Higgs Boson Decaying into W^{±}W^{∓} or ZZ in Fully Hadronic Final States from sqrt[s]=13 TeV pp Collisions Recorded with the ATLAS Detector

Several extensions of the Standard Model predict the production of dark matter particles at the LHC. An uncharted signature of dark matter particles produced in association with VV=W^{±}W^{∓} or ZZ pairs from a decay of a dark Higgs boson s is searched for using 139  fb^{-1} of pp collisions recorded by the ATLAS detector at a center-of-mass energy of 13 TeV. The s→V(qq[over ¯])V(qq[over ¯]) decays are reconstructed with a novel technique aimed at resolving the dense topology from boosted VV pairs using jets in the calorimeter and tracking information. Dark Higgs scenarios with m_{s}>160  GeV are excluded.

Venovenous extracorporeal membrane oxygenation for acute respiratory distress syndrome due to an acute type B aortic dissection: a case report

Acute type B aortic dissection is sometimes complicated by acute respiratory failure requiring mechanical ventilation. Herein, we describe our experience in a rare acute type B aortic dissection-associated respiratory failure case culminating in acute respiratory distress syndrome. The patient was a 45-year-old man admitted with a complaint of sudden chest pain radiating to his back. On computed tomography, an acute type B aortic dissection was diagnosed. He had no dyspnea on admission, but his respiratory function subsequently deteriorated, and severe acute respiratory distress syndrome was diagnosed on Day 4. Venovenous extracorporeal membrane oxygenation with anticoagulation plus continuous renal replacement therapy for oliguria improved the oxygenation, and the patient was weaned from the extracorporeal membrane oxygenation on Day 8. This patient fully recovered without worsening the aortic dissection, using venovenous extracorporeal membrane oxygenation with anticoagulation plus a continuous renal replacement therapy.

Medium-Induced Modification of Z-Tagged Charged Particle Yields in Pb+Pb Collisions at 5.02 TeV with the ATLAS Detector

The yield of charged particles opposite to a Z boson with large transverse momentum (p_{T}) is measured in 260  pb^{-1} of pp and 1.7  nb^{-1} of Pb+Pb collision data at 5.02 TeV per nucleon pair recorded with the ATLAS detector at the Large Hadron Collider. The Z boson tag is used to select hard-scattered partons with specific kinematics, and to observe how their showers are modified as they propagate through the quark-gluon plasma created in Pb+Pb collisions. Compared with pp collisions, charged-particle yields in Pb+Pb collisions show significant modifications as a function of charged-particle p_{T} in a way that depends on event centrality and Z boson p_{T}. The data are compared with a variety of theoretical calculations and provide new information about the medium-induced energy loss of partons in a p_{T} regime difficult to measure through other channels.

Impact of the combined use of intracardiac ultrasound and a steerable sheath visualized by a 3D mapping system on pulmonary vein isolation

BACKGROUND

A novel steerable sheath visualized on a three-dimensional mapping system has become available in this era in which a durable pulmonary vein (PV) isolation (PVI) with reduced fluoroscopy is required.

METHODS

In 60 patients who underwent a PVI with a visualized sheath (n = 30) and non-visualized conventional sheath (n = 30), the fluoroscopic time and catheter stability during the PVI were analyzed.

RESULTS

The fluoroscopic time during the transseptal access (0 [0, 0.1] vs. 1.4 [0.8, 2.3] minutes, P < .001) and PVI (0 [0, 0.1] vs. 0.4 [0.2, 1.1] minutes, P < .001) were shorter in the visualized sheath group than conventional sheath group. The procedure time during the PVI (32.0 [26.8, 36.3] vs. 41.0 [31.8, 47.3] minutes, P = .01), particularly during the right PVI (15.0 [12.8, 18.0] vs. 23.0 [15.8, 26.3] minutes, P = .009), was shorter in the visualized sheath group than conventional sheath group, however, that during the other steps was equivalent. The standard deviation of the catheter contact force during each radiofrequency application was smaller in the visualized sheath group than conventional sheath group (4.5 ± 2.7 vs. 4.9 ± 3.1 g, P = .001). The impedance drop for each lesion was larger in the visualized sheath group than conventional sheath group (10.7 ± 6.5 vs. 9.8 ± 5.5 ohms, P < .001). The incidence of acute PV reconnections per patient (30% vs. 23%, P = .56) and per PV segment (2.5% vs. 2.3%, P = .83) were similar between the two groups. No major complications occurred in either sheath group.

CONCLUSIONS

The use of visualized sheaths may reduce the fluoroscopic time and improve the catheter stability during the PVI.

Resetting of atrial tachycardia by a scanned extrastimulus at a downstream site on a multielectrode catheter: a simple diagnostic maneuver for locating the macroreentrant atrial tachycardia circuit

PURPOSE

Entrainment is a useful method for locating reentrant atrial tachycardia (AT) circuits, but alterations or termination of the AT can derail this process. We assessed whether resetting an upstream site of a neighboring electrode by a scanned extrastimulus at a downstream site (when the upstream tissue was refractory) could diagnose that site within the AT circuit.

METHODS

The procedure was applied to 48 ATs with a cycle length (CL) of 238 ± 42 ms (26 common flutters, 8 perimitral flutters, 7 left atrial [LA] roof-dependent AT, 3 LA scar-related macroreentrant ATs, 2 pulmonary vein-gap reentry tachycardias, 1 right atrial scar-related macroreentrant AT, and 1 with an unidentified circuit). Entrainment and scanned extrastimulation were attempted at the cavotricuspid isthmus, LA roof, and mitral isthmus and/or critical AT isthmus.

RESULTS

Within the circuit, the post-pacing interval minus the ATCL after entrainment was < 30 ms for all ATs and resetting of the AT cycle by ≥ 5 ms occurred in 94% of the ATs. No ATs were reset by extrastimulation outside the circuit. The positive predictive value of both maneuvers for locating the circuit was 100%, and the negative predictive value of the extrastimulation was similar to that of entrainment (96% vs. 100%, P = 0.25). The incidence of an AT alteration was lower with extrastimulation than with entrainment (1% vs. 9%, P = 0.01). For ATs with a CL < 210 ms, extrastimulation yielded a good diagnostic performance without any AT alterations.

CONCLUSION

AT resetting by a scanned extrastimulus is diagnostic and avoids AT alterations.

Observation and Measurement of Forward Proton Scattering in Association with Lepton Pairs Produced via the Photon Fusion Mechanism at ATLAS

The observation of forward proton scattering in association with lepton pairs (e^{+}e^{-}+p or μ^{+}μ^{-}+p) produced via photon fusion is presented. The scattered proton is detected by the ATLAS Forward Proton spectrometer, while the leptons are reconstructed by the central ATLAS detector. Proton-proton collision data recorded in 2017 at a center-of-mass energy of sqrt[s]=13  TeV are analyzed, corresponding to an integrated luminosity of 14.6  fb^{-1}. A total of 57 (123) candidates in the ee+p (μμ+p) final state are selected, allowing the background-only hypothesis to be rejected with a significance exceeding 5 standard deviations in each channel. Proton-tagging techniques are introduced for cross-section measurements in the fiducial detector acceptance, corresponding to σ_{ee+p}=11.0±2.6(stat)±1.2(syst)±0.3(lumi) and σ_{μμ+p}=7.2±1.6(stat)±0.9(syst)±0.2(lumi)  fb in the dielectron and dimuon channel, respectively.

Search for Heavy Resonances Decaying into a Photon and a Hadronically Decaying Higgs Boson in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter presents a search for the production of new heavy resonances decaying into a Higgs boson and a photon using proton-proton collision data at sqrt[s]=13  TeV collected by the ATLAS detector at the LHC. The data correspond to an integrated luminosity of 139  fb^{-1}. The analysis is performed by reconstructing hadronically decaying Higgs boson (H→bb[over ¯]) candidates as single large-radius jets. A novel algorithm using information about the jet constituents in the center-of-mass frame of the jet is implemented to identify the two b quarks in the single jet. No significant excess of events is observed above the expected background. Upper limits are set on the production cross-section times branching fraction for narrow spin-1 resonances decaying into a Higgs boson and a photon in the resonance mass range from 0.7 to 4 TeV, cross-section times branching fractions are excluded between 11.6 fb and 0.11 fb at a 95% confidence level.

Search for Higgs Boson Decays into a Z Boson and a Light Hadronically Decaying Resonance Using 13 TeV pp Collision Data from the ATLAS Detector

A search for Higgs boson decays into a Z boson and a light resonance in two-lepton plus jet events is performed, using a pp collision dataset with an integrated luminosity of 139  fb^{-1} collected at sqrt[s]=13  TeV by the ATLAS experiment at the CERN LHC. The resonance considered is a light boson with a mass below 4 GeV from a possible extended scalar sector or a charmonium state. Multivariate discriminants are used for the event selection and for evaluating the mass of the light resonance. No excess of events above the expected background is found. Observed (expected) 95% confidence-level upper limits are set on the Higgs boson production cross section times branching fraction to a Z boson and the signal resonance, with values in the range 17-340 pb (16_{-5}^{+6}-320_{-90}^{+130}  pb) for the different light spin-0 boson mass and branching fraction hypotheses, and with values of 110 and 100 pb (100_{-30}^{+40} and 100_{-30}^{+40}  pb) for the η_{c} and J/ψ hypotheses, respectively.

Dijet Resonance Search with Weak Supervision Using sqrt[s]=13 TeV pp Collisions in the ATLAS Detector

This Letter describes a search for narrowly resonant new physics using a machine-learning anomaly detection procedure that does not rely on signal simulations for developing the analysis selection. Weakly supervised learning is used to train classifiers directly on data to enhance potential signals. The targeted topology is dijet events and the features used for machine learning are the masses of the two jets. The resulting analysis is essentially a three-dimensional search A→BC, for m_{A}∼O(TeV), m_{B},m_{C}∼O(100  GeV) and B, C are reconstructed as large-radius jets, without paying a penalty associated with a large trials factor in the scan of the masses of the two jets. The full run 2 sqrt[s]=13  TeV pp collision dataset of 139  fb^{-1} recorded by the ATLAS detector at the Large Hadron Collider is used for the search. There is no significant evidence of a localized excess in the dijet invariant mass spectrum between 1.8 and 8.2 TeV. Cross-section limits for narrow-width A, B, and C particles vary with m_{A}, m_{B}, and m_{C}. For example, when m_{A}=3  TeV and m_{B}≳200  GeV, a production cross section between 1 and 5 fb is excluded at 95% confidence level, depending on m_{C}. For certain masses, these limits are up to 10 times more sensitive than those obtained by the inclusive dijet search. These results are complementary to the dedicated searches for the case that B and C are standard model bosons.