Search

Background: Preoperative malnutrition is a significant factor in patients with pancreatic tumors undergoing pancreaticoduodenectomy. The aim of this study was to assess the association between preoperative malnutrition and delayed discharge within a ten-day timeframe and potential correlations between preoperative malnutrition and postoperative surgical complications. Methods: A retrospective cohort study was conducted, recruiting a final sample of 79 patients with benign or malignant cephalic pancreatic tumors from 2015 to 2022. The risk of malnutrition was assessed using the Malnutrition Universal Screening Tool, while length of hospital stay and relevant clinical data were extracted from clinical documentation. Results: The preoperative malnutrition risk was high in 21.52% of the sample, moderate in 36.71%, and low in 41.77%. Body mass index (BMI) (p = 0.007) and postoperative surgical complications (p < 0.001) were significantly correlated with delayed discharge. No statistically significant differences were found between levels of malnutrition risk and delayed discharge (p = 0.122), or postoperative surgical complications (p = 0.874). Conclusions: Postoperative complications and BMI emerge as significant risk factors. The limited sample size may have compromised the collection of homogeneous and significant data. Future studies should evaluate the implementation of personalized nutritional screening tools, nutritional assessment plans, and the involvement of specialized health professionals.

Background/Aim: Nutrition is a key element of the prehabilitation process prior to surgery. The aim of this study was to identify the clinical pathways of nutritional prehabilitation before cystectomy. Methods: A systematic literature review was conducted in PubMed, the Cochrane Library, CINAHL, Scopus and the Web of Science databases. Quality and risk of bias assessment was conducted adhering to the JBI framework and evidence was evaluated according to the Oxford Centre for Evidence Based Medicine levels of evidence. Results: Out of 586 records identified, six studies were included. Among them, only two were randomized controlled trials. Immunonutrition has been shown to improve postoperative bowel function (3.12 vs. 3.74 days; RR 0.82; CI, 0.73–0.93; p = 0.0029) and decrease postoperative complications (−36.7%; p = 0.008) and readmission rates (−15.38%; p = 0.03). Furthermore, oral nutritional supplements combined with nutritional counseling demonstrated an accelerated recovery of bowel function (−1 day; p < 0.01), a reduction in the length of hospital stay (−1.75 days; p = 0.01), an improvement in handgrip strength (+6.8%, p < 0.001), an increase in bone mass (+0.3 kg, p = 0.04), and a better BMI value (+2.3%, p = 0.001). Conclusions: Nutritional prehabilitation demonstrates potential in enhancing postoperative outcomes following radical cystectomy. Oral supplements, immunonutrition, and counseling exhibit efficacy in improving postoperative results.

The associated production of Higgs and W bosons via vector-boson fusion is highly sensitive to the relative sign of the Higgs boson couplings to W and Z bosons. In this Letter, two searches for this process are presented, using 140  fb−1 of proton-proton collision data at s=13  TeV recorded by the ATLAS detector at the LHC. The first search targets scenarios with opposite-sign couplings of the W and Z bosons to the Higgs boson, while the second targets standard model-like scenarios with same-sign couplings. Both analyses consider Higgs boson decays into a pair of b quarks and W boson decays with an electron or muon. The data exclude the opposite-sign coupling hypothesis with a significance beyond 5σ, and the observed (expected) upper limit set on the cross section for vector-boson fusion WH production is 9.0 (8.7) times the standard model value at 95% confidence level. © 2024 CERN, for the ATLAS Collaboration 2024 CERN

The density of wood is a key indicator of the carbon investment strategies of trees, impacting productivity and carbon storage. Despite its importance, the global variation in wood density and its environmental controls remain poorly understood, preventing accurate predictions of global forest carbon stocks. Here we analyse information from 1.1 million forest inventory plots alongside wood density data from 10,703 tree species to create a spatially explicit understanding of the global wood density distribution and its drivers. Our findings reveal a pronounced latitudinal gradient, with wood in tropical forests being up to 30% denser than that in boreal forests. In both angiosperms and gymnosperms, hydrothermal conditions represented by annual mean temperature and soil moisture emerged as the primary factors influencing the variation in wood density globally. This indicates similar environmental filters and evolutionary adaptations among distinct plant groups, underscoring the essential role of abiotic factors in determining wood density in forest ecosystems. Additionally, our study highlights the prominent role of disturbance, such as human modification and fire risk, in influencing wood density at more local scales. Factoring in the spatial variation of wood density notably changes the estimates of forest carbon stocks, leading to differences of up to 21% within biomes. Therefore, our research contributes to a deeper understanding of terrestrial biomass distribution and how environmental changes and disturbances impact forest ecosystems.

Abstract: The ratio of branching ratios of the W boson to muons and electrons, $$R^{\,\mu /e}_W={{\mathcal {B}}(W\rightarrow \mu u )}$$ R W μ / e = B ( W → μ ν ) /$${{\mathcal {B}}(W\rightarrow eu )}$$ B ( W → e ν ) , has been measured using $$140\,\text{ fb}^{-1}\,$$ 140 fb - 1 of pp collision data at $$\sqrt{s}=13$$ s = 13  $$\text {T}\text {e}\hspace{-1.00006pt}\text {V}$$ Te V collected with the ATLAS detector at the LHC, probing the universality of lepton couplings. The ratio is obtained from measurements of the $$t\bar{t}$$ t t ¯ production cross-section in the ee, $$e\mu $$ e μ and $$\mu \mu $$ μ μ dilepton final states. To reduce systematic uncertainties, it is normalised by the square root of the corresponding ratio $$R^{\,\mu \mu /ee}_Z$$ R Z μ μ / e e for the Z boson measured in inclusive $$Z\rightarrow ee$$ Z → e e and $$Z\rightarrow \mu \mu $$ Z → μ μ events. By using the precise value of $$R^{\,\mu \mu /ee}_Z$$ R Z μ μ / e e determined from $$e^+e^-$$ e + e - colliders, the ratio $$R^{\,\mu /e}_W$$ R W μ / e is determined to be $$\begin{aligned} R^{\,\mu /e}_W&= 0.9995\pm 0.0022\,\mathrm {(stat)}\,\pm 0.0036\,\mathrm {(syst)}\\ &\quad \pm 0.0014\,\mathrm {(ext)} . \end{aligned}$$ R W μ / e = 0.9995 ± 0.0022 ( stat ) ± 0.0036 ( syst ) ± 0.0014 ( ext ) . The three uncertainties correspond to data statistics, experimental systematics and the external measurement of $$R^{\,\mu \mu /ee}_Z$$ R Z μ μ / e e , giving a total uncertainty of 0.0045, and confirming the Standard Model assumption of lepton flavour universality in W-boson decays at the 0.5% level.

Abstract: Pixel sensors in 3D technology equip the outer ends of the staves of the Insertable B Layer (IBL), the innermost layer of the ATLAS Pixel Detector, which was installed before the start of LHC Run 2 in 2015. 3D pixel sensors are expected to exhibit more tolerance to radiation damage and are the technology of choice for the innermost layer in the ATLAS tracker upgrade for the HL-LHC programme. While the LHC has delivered an integrated luminosity of  ≃ 235 fb-1 since the start of Run 2, the 3D sensors have received a non-ionising energy deposition corresponding to a fluence of ≃ 8.5 × 1014 1 MeV neutron-equivalent cm-2 averaged over the sensor area. This paper presents results of measurements of the 3D pixel sensors' response during Run 2 and the first two years of Run 3, with predictions of its evolution until the end of Run 3 in 2025. Data are compared with radiation damage simulations, based on detailed maps of the electric field in the Si substrate, at various fluence levels and bias voltage values. These results illustrate the potential of 3D technology for pixel applications in high-radiation environments.

Tree growth and longevity trade-offs fundamentally shape the terrestrial carbon balance. Yet, we lack a unified understanding of how such trade-offs vary across the world's forests. By mapping life history traits for a wide range of species across the Americas, we reveal considerable variation in life expectancies from 10 centimeters in diameter (ranging from 1.3 to 3195 years) and show that the pace of life for trees can be accurately classified into four demographic functional types. We found emergent patterns in the strength of trade-offs between growth and longevity across a temperature gradient. Furthermore, we show that the diversity of life history traits varies predictably across forest biomes, giving rise to a positive relationship between trait diversity and productivity. Our pan-latitudinal assessment provides new insights into the demographic mechanisms that govern the carbon turnover rate across forest biomes.

Results from a wide range of searches targeting different experimental signatures with and without missing transverse momentum (ETmiss) are used to constrain a Two-Higgs-Doublet Model (2HDM) with an additional pseudo-scalar mediating the interaction between ordinary and dark matter (2HDM+a). The analyses use up to 139 fb-1 of proton-proton collision data at a centre-of-mass energy s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider during 2015-2018. The results from three of the most sensitive searches are combined statistically. These searches target signatures with large ETmiss and a leptonically decaying Z boson; large ETmiss and a Higgs boson decaying to bottom quarks; and production of charged Higgs bosons in final states with top and bottom quarks, respectively. Constraints are derived for several common and new benchmark scenarios in the 2HDM+a.

This paper presents a search for exotic decays of the Higgs boson into a pair of new pseudoscalar particles, H→aa, where one pseudoscalar decays into a b-quark pair and the other decays into a τ-lepton pair, in the mass range 12≤ma≤60  GeV. The analysis uses pp collision data at s=13  TeV collected with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 140  fb−1. No significant excess above the Standard Model (SM) prediction is observed. Assuming the SM Higgs boson production cross section, the search sets upper limits at 95% confidence level on the branching ratio of Higgs bosons decaying into bb¯τ+τ−, B(H→aa→bb¯τ+τ−), between 2.2% and 3.9% depending on the pseudoscalar mass. © 2024 CERN, for the ATLAS Collaboration 2024 CERN

Abstract: This paper presents a measurement of the production cross-section of a Z boson in association with b- or c-jets, in proton–proton collisions at $$\sqrt{s} = 13$$ s = 13 TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of 140 $$\hbox {fb}^{-1}$$ fb - 1 . Inclusive and differential cross-sections are measured for events containing a Z boson decaying into electrons or muons and produced in association with at least one b-jet, at least one c-jet, or at least two b-jets with transverse momentum $$p_\text {T} > 20$$ p T > 20 GeV and rapidity $$|y| < 2.5$$ | y | < 2.5 . Predictions from several Monte Carlo generators based on next-to-leading-order matrix elements interfaced with a parton-shower simulation, with different choices of flavour schemes for initial-state partons, are compared with the measured cross-sections. The results are also compared with novel predictions, based on infrared and collinear safe jet flavour dressing algorithms. Selected $$Z + \ge 1~c$$ Z + ≥ 1 c -jet observables, optimized for sensitivity to intrinsic-charm, are compared with benchmark models with different intrinsic-charm fractions.

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 2.4 assuming no Higgs boson pair production. Constraints on the Higgs boson self-coupling modifier κ_{λ}=λ_{HHH}/λ_{HHH}^{SM}, and the quartic HHVV coupling modifier κ_{2V}=g_{HHVV}/g_{HHVV}^{SM}, are derived individually, fixing the other parameter to its SM value. The observed 95% CL intervals are -1.2

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. A nonzero fraction of events with two longitudinally polarized bosons is measured with an observed significance of 5.3 standard deviations in the region with 100200  GeV, where pTZ is the transverse momentum of the Z boson. This Letter also reports the first study of the radiation-amplitude-zero effect. Events with two transversely polarized bosons are analyzed for the ΔY(ℓWZ) and ΔY(WZ) distributions defined respectively as the rapidity difference between the lepton from the W boson decay and the Z boson and the rapidity difference between the W boson and the Z boson. Significant suppression of events near zero is observed in both distributions. Unfolded ΔY(ℓWZ) and ΔY(WZ) distributions are also measured and compared to theoretical predictions. © 2024 CERN, for the ATLAS Collaboration 2024 CERN

A search is presented for the pair production of heavy vectorlike quarks (VLQs) that each decay into a W boson and a light quark. This study focuses on events where one W boson decays into leptons and the other into hadrons. The search analyzed 140  fb−1 of pp collision data with s=13  TeV, recorded by the ATLAS detector from 2015 to 2018 during run 2 of the Large Hadron Collider. The final state is characterized by a high-transverse-momentum isolated electron or muon, large missing transverse momentum, multiple small-radius jets, and a single large-radius jet identified as originating from the hadronic decay of a boosted W boson. With higher center-of-mass energy and integrated luminosity than in the run 1 search, and improved analysis tools, this analysis excludes VLQs (Q) with masses below 1530 GeV at 95% confidence level for the branching ratio B(Q→Wq)=1, an improvement of 840 GeV on the previous ATLAS limit. © 2024 CERN, for the ATLAS Collaboration 2024 CERN

A search for heavy Majorana neutrinos in scattering of same-sign W boson pairs in proton–proton collisions at s=13 TeV at the LHC is reported. The dataset used corresponds to an integrated luminosity of 140 fb−1, collected with the ATLAS detector during 2015–2018. The search is performed in final states including a same-sign ee or eμ pair and at least two jets with large invariant mass and a large rapidity difference. No significant excess of events with respect to the Standard Model background predictions is observed. The results are interpreted in a benchmark scenario of the Phenomenological Type-I Seesaw model. New constraints are set on the values of the |VeN|2 and |VeNVμN⁎| parameters for heavy Majorana neutrino masses between 50 GeV and 20 TeV, where VℓN is the matrix element describing the mixing of the heavy Majorana neutrino mass eigenstate with the Standard Model neutrino of flavour ℓ=e,μ. The sensitivity to the Weinberg operator is investigated and constraints on the effective ee and eμ Majorana neutrino masses are reported. The statistical combination of the ee and eμ channels with the previously published μμ channel is performed.

This quantitative-correlational study aimed to examine the relationship between online game addiction and mental well-being of high school students from Angeles City, in the Philippines, during the COVID-19 pandemic. To obtain data from the respondents, the Internet Gaming Disorder Scale--Short-Form and Depression, Anxiety, and Stress Scale (DASS-21) were utilised. After obtaining data from purposively selected 162 high-school students, it was observed that there was a positive and significant relationship between online game addiction and mental well-being. The study highlighted that individuals who are highly dependent on online games are more likely to experience higher levels of depression, anxiety and stress. Based on the findings, implications for theory and practice, particularly in learning and development, are presented, along with recommendations for schools, teachers, students, and future research directions.

Deaf-blindness is a type of dual disability wherein visual and auditory capabilities are significantly impaired. Special communication methods have been developed for the deaf-blind community. Yet, these methods require that both people involved have prior knowledge and training to successfully communicate, limiting deaf-blind people's social interactions, particularly in academic settings. This paper describes the development of a device that enables two-way communication between a severely deaf-blind user and a hearing person with no prior knowledge of Braille and no additional intermediaries. A Convolutional Neural Network (CNN) scheme for speech recognition was designed and implemented along with the development of an algorithm capable of developing both text-to-speech and Finger-Braille-to-text conversion. Lastly, a system integration via 3D modeling and additive manufacturing was carried out to deliver a functional prototype. The resulting device aims to allow deaf-blind students to send and receive information entirely in finger Braille, using buttons and vibrotactile feedback. In contrast, the hearing tutor receives auditory messages and speaks to reply, making the educational experience as familiar as possible for both parties. Users testing the device achieved an average typing accuracy of over 95% and demonstrated an understanding of commands transmitted through the device's components.

The need for online educational tools has increased significantly since the COVID-19 pandemic forced many students to embrace distance learning as a classroom alternative. While many instructors have used "Edpuzzle" to enhance distance learning, there has been little research that assesses and compares the views of teachers and students on the tool's advantages and disadvantages. To examine the perceived advantages and disadvantages of using "Edpuzzle" for classroom learning, we surveyed a sample of 152 professors and their students on their experience with the tool. The results reveal numerous advantages, including that "Edpuzzle" is a motivating, dynamic, and novel self-learning tool for students. Likewise, the professors point out that it is easy to use, focuses the attention of students, and is versatile. The disadvantages of the tool mostly had to do with technological challenges and potential boredom. Based on this evaluation, it was concluded that students have a preference for graphic and visual material to complement other learning tools to help them better understand the lessons. When weighing the advantages and disadvantages posed by the professors and their students, it was found that the unique combination of interactive teaching that "Edpuzzle" provides is promising for the future.

The present study investigates the students' perceptions of applying performance tasks based on the GRASPS framework, exploring and seeking to explain the relationships between these tasks and English language learning. Data was collected over one semester in 14 public secondary schools in Ecuador, and it consisted of a questionnaire applied to 283 EFL students and two focus-group interviews with 12 EFL learners. After receiving a two-week workshop, sixteen Ecuadorian EFL teachers planned three units following the three stages based on the Backward Design Model (Wiggings & McTigue, 2005); however, this study focuses on the students' perceptions of the GRASPS framework. Overall, the students showed high levels of awareness of the benefits of developing performance tasks based on the GRASPS framework. The main benefits encountered by these students were improving English skills, fostering creativity, and autonomous and lifelong learning. Subsequently, the primary takeaway from this study proposes applying the GRASPS framework as a potential support for EFL learning. Theoretical and practical implications are presented, and further research suggestions are provided.

Attending college, for many immigrant families, is a critical step in achieving the American Dream. This essay, written as a reflection and response between professor and student, explores the conflicting messages young community college students negotiate and process as they move through the City, revealing how knowledge learned in the college classroom is imbued with value beyond that knowledge that they have learned in their homes and neighborhoods. It shares how a research interest from their professor in the knowledge and practices their families have to teach was a point of processing and potential reconciliation of these conflicts related shifting identities, and notes the potential therapeutic value of the embodiment of heritage practices as part of ethnographic research and beyond.

Charged particle reconstruction in the presence of many simultaneous proton–proton (pp) collisions in the LHC is a challenging task for the ATLAS experiment’s reconstruction software due to the combinatorial complexity. This paper describes the major changes made to adapt the software to reconstruct high-activity collisions with an average of 50 or more simultaneous pp interactions per bunch crossing (pile-up) promptly using the available computing resources. The performance of the key components of the track reconstruction chain and its dependence on pile-up are evaluated, and the improvement achieved compared to the previous software version is quantified. For events with an average of 60pp collisions per bunch crossing, the updated track reconstruction is twice as fast as the previous version, without significant reduction in reconstruction efficiency and while reducing the rate of combinatorial fake tracks by more than a factor two.

Photosynthesis-the conversion of energy from sunlight into chemical energy-is essential for life on Earth. Yet there is much we do not understand about photosynthetic energy conversion on a fundamental level: how it evolved and the extent of its diversity, its dynamics, and all the components and connections involved in its regulation. In this commentary, researchers working on fundamental aspects of photosynthesis including the light-dependent reactions, photorespiration, and C4 photosynthetic metabolism pose and discuss what they view as the most compelling open questions in their areas of research.

We combine design-based implementation research with a pre-registered RCT to address a long-standing challenge in psychological science: How to use psychological principles to address real-world problems while designing and implementing interventions in the field. We posit this as a design methodology for optimizing the translation between psychological science and real-world applications. We tested the efficacy of an extensively co-designed version of a game-based rational number intervention, Fraction Ball, versus “business-as-usual” math instruction and physical education in a sample of 4th/5th grade Latine students (N = 360). Insights from nine co-design sessions with 20 teachers informed revisions and additions to a previous version of Fraction Ball, strengthening impacts across 10 of 12 rational number subtests. This methodology provides insights for translating psychological science research and scaling it to address real-world educational needs, such as play-based interventions that improve rational number understanding in authentic contexts.

BackgroundIt is unknown if early COVID-19 monoclonal antibody (mAb) therapy can reduce risk of Long COVID. The mAbs amubarvimab/romlusevimab were previously demonstrated to reduce risk of hospitalization/death by 79%. This study assessed the impact of amubarvimab/romlusevimab on late outcomes, including Long COVID.MethodsNon-hospitalized high-risk adults within 10 days of COVID-19 symptom onset enrolled in a randomized, double-blind, placebo-controlled phase 2/3 trial of amubarvimab/romlusevimab for COVID-19 treatment. Late symptoms, assessed using a participant-completed symptom diary, were a pre-specified exploratory endpoint. The primary outcome for this analysis was the composite of Long COVID by participant self-report (presence of COVID-19 symptoms as recorded in the diary at week 36) or hospitalization or death by week 36. Inverse probability weighting (IPW) was used to address incomplete outcome ascertainment, giving weighted risk ratios (wRR) comparing amubarvimab/romlusevimab to placebo.FindingsParticipants received amubarvimab/romlusevimab (n = 390) or placebo (n = 390) between January and July 2021. Median age was 49 years, 52% were female, 18% Black/African American, 49% Hispanic/Latino, and 9% COVID-19-vaccinated at entry. At week 36, 103 (13%) had incomplete outcome ascertainment, and 66 (17%) on amubarvimab/romlusevimab and 92 (24%) on placebo met the primary outcome (wRR = 0.70, 95% confidence interval (CI) 0.53-0.93). The difference was driven by fewer hospitalizations/deaths with amubarvimab/romlusevimab (4%) than placebo (13%). Among 652 participants with available diary responses, 53 (16%) on amubarvimab/romlusevimab and 44 (14%) on placebo reported presence of Long COVID.InterpretationAmubarvimab/romlusevimab treatment, while highly effective in preventing hospitalizations/deaths, did not reduce risk of Long COVID. Additional interventions are needed to prevent Long COVID.FundingNational Institute of Allergy and Infectious Diseases of the National Institutes of Health. Amubarvimab and romlusevimab supplied by Brii Biosciences.

Several processes studied by the ATLAS experiment at the Large Hadron Collider produce low-momentum b-flavored hadrons in the final state. This paper describes the calibration of a dedicated tagging algorithm that identifies b-flavored hadrons outside of hadronic jets by reconstructing the soft secondary vertices originating from their decays. The calibration is based on a proton-proton collision dataset at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 140  fb−1. Scale factors used to correct the algorithm’s performance in simulated events are extracted for the b-tagging efficiency and the mistag rate of the algorithm using a data sample enriched in tt¯ events. Several orthogonal measurement regions are defined, binned as a function of the multiplicities of soft secondary vertices and jets containing a b-flavored hadron in the event. The mistag rate scale factors are estimated separately for events with low and high average numbers of interactions per bunch crossing. The results, which are derived from events with low missing transverse momentum, are successfully validated in a phase space characterized by high missing transverse momentum and therefore are applicable to new physics searches carried out in either phase space regime. © 2024 CERN, for the ATLAS Collaboration 2024 CERN

A search for the nonresonant production of Higgs boson pairs in the HH→bb¯τ+τ− channel is performed using 140  fb−1 of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The analysis strategy is optimized to probe anomalous values of the Higgs boson self-coupling modifier κλ and of the quartic HHVV (V=W,Z) coupling modifier κ2V. No significant excess above the expected background from Standard Model processes is observed. An observed (expected) upper limit μHH

Abstract: The identification of top quark decays where the top quark has a large momentum transverse to the beam axis, known as top tagging, is a crucial component in many measurements of Standard Model processes and searches for beyond the Standard Model physics at the Large Hadron Collider.Machine learning techniques have improved the performance of top tagging algorithms, but the size of the systematic uncertainties for all proposed algorithms has not been systematically studied.This paper presents the performance of several machine learning based top tagging algorithms on a dataset constructed from simulated proton-proton collision events measured with the ATLAS detector at √ s = 13 TeV.The systematic uncertainties associated with these algorithms are estimated through an approximate procedure that is not meant to be used in a physics analysis, but is appropriate for the level of precision required for this study.The most performant algorithms are found to have the largest uncertainties, motivating the development of methods to reduce these uncertainties without compromising performance.To enable such efforts in the wider scientific community, the datasets used in this paper are made publicly available.

A search is performed for localized excesses in the low-mass dijet invariant mass distribution, targeting a hypothetical new particle decaying into two jets and produced in association with either a high transverse momentum photon or a jet. The search uses the full Run 2 data sample from LHC proton-proton collisions collected by the ATLAS experiment at a center-of-mass energy of 13 TeV during 2015–2018. Two variants of the search are presented for each type of initial-state radiation: one that makes no jet flavor requirements and one that requires both of the jets to have been identified as containing b-hadrons. No excess is observed relative to the Standard Model prediction, and the data are used to set upper limits on the production cross section for a benchmark Z′ model and, separately, for generic, beyond the Standard Model scenarios which might produce a Gaussian-shaped contribution to dijet invariant mass distributions. The results extend the current constraints on dijet resonances to the mass range between 200 and 650 GeV. © 2024 CERN, for the ATLAS Collaboration 2024 CERN

A measurement of the Standard Model Higgs boson produced in association with a W or Z boson and decaying into a pair of τ-leptons is presented. This search is based on proton-proton collision data collected at s=13 TeV by the ATLAS experiment at the LHC corresponding to an integrated luminosity of 140 fb−1. For the Higgs boson candidate, only final states with at least one τ-lepton decaying hadronically (τ→hadrons+ντ) are considered. For the vector bosons, only leptonic decay channels are considered: Z→ℓℓ and W→ℓνℓ, with ℓ=e,μ. An excess of events over the expected background is found with an observed (expected) significance of 4.2 (3.6) standard deviations, providing evidence of the Higgs boson produced in association with a vector boson and decaying into a pair of τ-leptons. The ratio of the measured cross-section to the Standard Model prediction is μVHττ=1.28−0.29+0.30(stat.)−0.21+0.25(syst.). This result represents the most accurate measurement of the VH(ττ) process achieved to date.

This paper reports cross-section measurements of ZZ production in pp collisions at s=13.6TeV at the Large Hadron Collider. The data were collected by the ATLAS detector in 2022, and correspond to an integrated luminosity of 29 fb−1. Events in the ZZ→4ℓ (ℓ=e, μ) final states are selected and used to measure the inclusive and differential cross-sections in a fiducial region defined close to the analysis selections. The inclusive cross-section is further extrapolated to the total phase space with a requirement of 66

Searches for exclusive decays of the Higgs boson into D⁎γ and of the Z boson into D0γ and Ks0γ can probe flavour-violating Higgs boson and Z boson couplings to light quarks. Searches for these decays are performed with a pp collision data sample corresponding to an integrated luminosity of 136.3 fb−1 collected at s=13TeV between 2016–2018 with the ATLAS detector at the CERN Large Hadron Collider. In the D⁎γ and D0γ channels, the observed (expected) 95% confidence-level upper limits on the respective branching fractions are B(H→D⁎γ)

Abstract: A search is presented for flavour-changing neutral-current interactions involving the top quark, the Higgs boson and an up-type quark ($$q=u,c$$ q = u , c ) with the ATLAS detector at the Large Hadron Collider. The analysis considers leptonic decays of the top quark along with Higgs boson decays into two $$W$$ W bosons, two $$Z$$ Z bosons or a $$\tau ^{+}\tau ^{-}$$ τ + τ - pair. It focuses on final states containing either two leptons (electrons or muons) of the same charge or three leptons. The considered processes are $$t\bar{t}$$ t t ¯ and Ht production. For the $$t\bar{t}$$ t t ¯ production, one top quark decays via $$t\rightarrow Hq$$ t → H q . The proton–proton collision data set analysed amounts to $$({140}\,{\hbox {fb}^{-1}})$$ ( 140 fb - 1 ) at $$(\sqrt{s}={13}\,\hbox {TeV})$$ ( s = 13 TeV ) . No significant excess beyond Standard Model expectations is observed and upper limits are set on the $$t\rightarrow Hq$$ t → H q branching ratios at 95 % confidence level, amounting to observed (expected) limits of $$\mathcal {B}(t\rightarrow Hu)

Abstract: Presented is the search for anomalous Higgs boson decays into two axion-like particles (ALPs) using the full Run 2 data set of $$140\,\text {fb}^{-1}$$ 140 fb - 1 of proton-proton collisions at a centre-of-mass energy of $$13\,\text {TeV}$$ 13 TeV recorded by the ATLAS experiment. The ALPs are assumed to decay into two photons, providing sensitivity to recently proposed models that could explain the $$(g-2)_\mu $$ ( g - 2 ) μ discrepancy. This analysis covers an ALP mass range from 100 to $$62\,\text {GeV}$$ 62 GeV and ALP-photon couplings in the range $$10^{-7}\,\text {TeV}^{-1} 10 - 7 TeV - 1 < C a γ γ / Λ < 1 TeV - 1 , and therefore includes signatures with significantly displaced vertices and highly collinear photons. No significant excess of events above the Standard Model background is observed. Upper limits at 95% confidence level are placed on the branching ratio of the Higgs boson to two ALPs in the four-photon final state, and are in the range of $$ 10^{-5}$$ 10 - 5 to $$3\times 10^{-2}$$ 3 × 10 - 2 , depending on the hypothesized ALP mass and ALP-photon coupling strength.

A search for charged-lepton-flavor violating μτqt (q=u, c) interactions is presented, considering both top-quark production and decay. The data analyzed correspond to 140  fb−1 of proton-proton collisions at a center-of-mass energy of s=13  TeV recorded with the ATLAS detector at the Large Hadron Collider. The analysis targets events containing two muons with the same electric charge, a hadronically decaying τ-lepton and at least one jet, with exactly one b-tagged jet, produced by a μτqt interaction. Agreement with the Standard Model expectation within 1.6 standard deviations is observed, and limits are set at the 95% confidence level (CL) on the charged-lepton-flavor violation branching ratio of B(t→μτq)

Abstract: A search is reported for long-lived dark photons with masses between 0.1 GeV and 15 GeV, from exotic decays of Higgs bosons produced via vector-boson-fusion. Events that contain displaced collimated Standard Model fermions reconstructed in the calorimeter or muon spectrometer are probed. This search uses the full LHC Run 2 (2015–2018) data sample collected in proton–proton collisions at $$\sqrt{s}=13$$ s = 13 TeV, corresponding to an integrated luminosity of 139 $$fb^{-1}$$ f b - 1 . Dominant backgrounds from Standard Model processes and non-collision sources are estimated using data-driven techniques. The observed event yields in the signal regions are consistent with the expected background. Upper limits on the Higgs boson to dark photon branching fraction are reported as a function of the dark photon mean proper decay length or of the dark photon mass and the coupling between the Standard Model and the potential dark sector. This search is combined with previous ATLAS searches obtained in the gluon–gluon fusion and WH production modes. A branching fraction above 10% is excluded at 95% CL for a 125 GeV Higgs boson decaying into two dark photons for dark photon mean proper decay lengths between 173 and 1296 mm and mass of 10 GeV.

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.L. cross-section upper limits by 15%-40%.

Frontotemporal dementia (FTD) is the second most common cause of early-onset dementia after Alzheimer disease (AD). Efforts in the field mainly focus on familial forms of disease (fFTDs), while studies of the genetic etiology of sporadic FTD (sFTD) have been less common. In the current work, we analyzed 4,685 sFTD cases and 15,308 controls looking for common genetic determinants for sFTD. We found a cluster of variants at the MAPT (rs199443; p = 2.5 × 10-12, OR = 1.27) and APOE (rs6857; p = 1.31 × 10-12, OR = 1.27) loci and a candidate locus on chromosome 3 (rs1009966; p = 2.41 × 10-8, OR = 1.16) in the intergenic region between RPSA and MOBP, contributing to increased risk for sFTD through effects on expression and/or splicing in brain cortex of functionally relevant in-cis genes at the MAPT and RPSA-MOBP loci. The association with the MAPT (H1c clade) and RPSA-MOBP loci may suggest common genetic pleiotropy across FTD and progressive supranuclear palsy (PSP) (MAPT and RPSA-MOBP loci) and across FTD, AD, Parkinson disease (PD), and cortico-basal degeneration (CBD) (MAPT locus). Our data also suggest population specificity of the risk signals, with MAPT and APOE loci associations mainly driven by Central/Nordic and Mediterranean Europeans, respectively. This study lays the foundations for future work aimed at further characterizing population-specific features of potential FTD-discriminant APOE haplotype(s) and the functional involvement and contribution of the MAPT H1c haplotype and RPSA-MOBP loci to pathogenesis of sporadic forms of FTD in brain cortex.

Fiducial and total W± and Z boson cross sections, their ratios and the ratio of top-antitop-quark pair and W-boson fiducial cross sections are measured in proton–proton collisions at a centre-of-mass energy of s=13.6 TeV, corresponding to an integrated luminosity of 29 fb−1 of data collected in 2022 by the ATLAS experiment at the Large Hadron Collider. The measured fiducial cross-section values for W+→ℓ+ν, W−→ℓ−ν¯, and Z→ℓ+ℓ− (ℓ=e or μ) boson productions are 4250±150 pb, 3310±120 pb, and 744±20 pb, respectively, where the uncertainty is the total uncertainty, including that arising from the luminosity of about 2.2%. The measurements are in agreement with Standard-Model predictions calculated at next-to-next-to-leading-order in αs, next-to-next-to-leading logarithmic accuracy and next-to-leading-order electroweak accuracy.

A search is presented for the pair-production of heavy vector-like quarks in the lepton+jets final state using 140 fb−1 of proton–proton collisions at s=13 TeV collected with the ATLAS detector. The search is optimised for vector-like top-quarks (T) that decay into a W boson and a b-quark, with one W boson decaying leptonically and the other hadronically. Other vector-like quark flavours and decay modes are also considered. Events are selected with one high transverse-momentum electron or muon, large missing transverse momentum, a large-radius jet identified as a W boson, and multiple small-radius jets, at least one of which is b-tagged. Vector-like T-quarks with 100% branching ratio to Wb are excluded at 95% CL for masses below 1700 GeV. These limits are also applied to vector-like Y-quarks, which decay exclusively into a W boson and a b-quark. Isospin singlets with B(T→Wb:Ht:Zt)=1/2:1/4:1/4 are excluded for masses below 1360 GeV.

A measurement of the invisible width of the Z boson using events with jets and missing transverse momentum is presented using 37 fb−1 of 13 TeV proton–proton data collected by the ATLAS detector in 2015 and 2016. The ratio of Z→inv to Z→ℓℓ events, where inv refers to non-detected particles and ℓ is either an electron or a muon, is measured and corrected for detector effects. Events with at least one energetic central jet with pT≥110 GeV are selected for both the Z→inv and Z→ℓℓ final states to obtain a similar phase space in the ratio. The invisible width is measured to be 506±2(stat.)±12(syst.) MeV and is the single most precise recoil-based measurement. The result is in agreement with the most precise determination from LEP and the Standard Model prediction based on three neutrino generations.

A statistical combination of various searches for pair-produced leptoquarks is presented, using the full LHC Run 2 (2015–2018) data set of 139 fb−1 collected with the ATLAS detector from proton–proton collisions at a centre-of-mass energy of s=13 TeV. All possible decays of the leptoquarks into quarks of the third generation and charged or neutral leptons of any generation are investigated. Since no significant deviations from the Standard Model expectation are observed in any of the individual analyses, combined exclusion limits are set on the production cross-sections for scalar and vector leptoquarks. The resulting lower bounds on leptoquark masses exceed those from the individual analyses by up to 100 GeV, depending on the signal hypothesis.

The observation of the electroweak production of single-top-quarks is made using 255 pb−1 of proton-proton collision data recorded at s=5.02 TeV with the ATLAS detector at the Large Hadron Collider. An event selection is used to identify single-top-quark candidates arising from t-channel production with the top quark decaying semi-leptonically. Events passing the selection are then used to measure the inclusive cross-section for the combined production of single-top-quarks and antiquarks, σ(tq+t¯q), and the ratio Rt between these two. They are measured to be σ(tq+t¯q)=27.1−4.1+4.4(stat.)−3.7+4.4(syst.) pb and Rt=2.73−0.82+1.43(stat.)−0.29+1.01(syst.). The individual single-top-quark (tq) and single-top-antiquark (t¯q) production cross-sections are measured to be σ(tq)=19.8−3.1+3.9(stat.)−2.2+2.9(syst.) pb and σ(t¯q)=7.3−2.1+3.2(stat.)−1.5+2.8(syst.) pb. All measurements are in good agreement with the Standard Model predictions.

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. The observed (expected) limits are in the range 0.96-600 fb (1.2-390 fb). The limits are interpreted in the type-I two-Higgs-doublet model and the minimal supersymmetric standard model, and constrain parameter space not previously excluded by other searches.

The ATLAS trigger system is a crucial component of the ATLAS experiment at the LHC. It is responsible for selecting events in line with the ATLAS physics programme. This paper presents an overview of the changes to the trigger and data acquisition system during the second long shutdown of the LHC, and shows the performance of the trigger system and its components in the proton-proton collisions during the 2022 commissioning period as well as its expected performance in proton-proton and heavy-ion collisions for the remainder of the third LHC data-taking period (2022–2025).

Measurements of the substructure of top-quark jets are presented, using Formula Presented of 13 TeV Formula Presented collision data recorded with the ATLAS detector at the LHC. Top-quark jets reconstructed with the anti-Formula Presented algorithm with a radius parameter Formula Presented are selected in top-quark pair (Formula Presented) events where one top quark decays semileptonically and the other hadronically, or where both top quarks decay hadronically. The top-quark jets are required to have transverse momentum Formula Presented, yielding large samples of data events with jet Formula Presented values between 350 and 600 GeV. One- and two-dimensional differential cross sections for eight substructure variables, defined using only the charged components of the jets, are measured in a particle-level phase space by correcting for the smearing and acceptance effects induced by the detector. The differential cross sections are compared with the predictions of several Monte Carlo simulations in which top-quark pair-production quantum chromodynamic matrix-element calculations at next-to-leading-order precision in the strong coupling constant Formula Presented are passed to leading-order parton shower and hadronization generators. The Monte Carlo predictions for measures of the broadness, and also the two-body structure, of the top-quark jets are found to be in good agreement with the measurements, while variables sensitive to the three-body structure of the top-quark jets exhibit some tension with the measured distributions.

A search for the single production of a vectorlike top partner (Formula Presented) with mass greater than 1 TeV decaying into a Formula Presented boson and a top quark is presented, using the full Run 2 dataset corresponding to Formula Presented of Formula Presented collisions at Formula Presented, collected in 2015-2018 with the ATLAS detector at the Large Hadron Collider. The targeted final state is characterized by the presence of a pair of electrons or muons with opposite-sign charges which form a Formula Presented-boson candidate, as well as by the presence of Formula Presented-tagged jets and forward jets. Events with exactly two or at least three leptons are categorized into two independently optimized analysis channels. No significant excess above the background expectation is observed and the results from the two channels are statistically combined to set exclusion limits at 95% confidence level on the masses and couplings of Formula Presented. The results are interpreted in several benchmark scenarios to set limits on the mass and universal coupling strength (Formula Presented) of the vectorlike quark. For singlet Formula Presented quarks, Formula Presented values between 0.22 and 0.64 are excluded for masses between 1000 and 1975 GeV. For Formula Presented quarks in the doublet scenario, where the production cross section is much lower, Formula Presented values between 0.54 and 0.88 are excluded for masses between 1000 and 1425 GeV.

This paper presents a search for pair production of higgsinos, the supersymmetric partners of the Higgs bosons, in scenarios with gauge-mediated supersymmetry breaking. Each higgsino is assumed to decay into a Higgs boson and a nearly massless gravitino. The search targets events where each Higgs boson decays into Formula Presented, leading to a reconstructed final state with at least three energetic Formula Presented-jets and missing transverse momentum. Two complementary analysis channels are used, with each channel specifically targeting either low or high values of the higgsino mass. The low-mass (high-mass) channel exploits Formula Presented of Formula Presented data collected by the ATLAS detector during Run 2 of the Large Hadron Collider. No significant excess above the Standard Model prediction is found. At 95% confidence level, masses between 130 GeV and 940 GeV are excluded for higgsinos decaying exclusively into Higgs bosons and gravitinos. Exclusion limits as a function of the higgsino decay branching ratio to a Higgs boson are also reported.