Confidence-level Limits Research Articles

Combination of searches for singly produced vectorlike top quarks in pp collisions at s=13 TeV with the ATLAS detector

A combination of searches for the single production of vectorlike top quarks (T) is presented. These analyses are based on proton-proton collisions at s=13 TeV recorded in 2015–2018 with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. The T decay modes considered in this combination are into a top quark and either a Standard Model Higgs boson or a Z boson (T→Ht and T→Zt). The individual searches used in the combination are differentiated by the number of leptons (e, μ) in the final state. The observed data are found to be in good agreement with the Standard Model background prediction. Interpretations are provided for a range of masses and couplings of the vectorlike top quark for benchmark models and generalized representations in terms of 95% confidence level limits. For a benchmark signal prediction of a vectorlike top quark SU(2) singlet with electroweak coupling, κ, of 0.5, masses below 2.1 TeV are excluded, resulting in the most restrictive limits to date. © 2025 CERN, for the ATLAS Collaboration 2025 CERN

Search for new particles in events with a hadronically decaying W or Z boson and large missing transverse momentum at s = 13 TeV using the ATLAS detector

A search is presented for new particles produced in proton-proton collisions at a centre-of-mass energy of 13 TeV that result in final states comprising a massive vector (W or Z) boson that decays hadronically and large missing transverse momentum. The data sample was collected with the ATLAS experiment at the Large Hadron Collider from 2015 to 2018 and corresponds to an integrated luminosity of 140 fb−1. No significant excess over the Standard Model expectation is observed. Model-independent 95% confidence-level limits on the visible cross-section that range from 0.3 fb to 79.5 fb are obtained for non-Standard-Model processes. Exclusion limits are also presented for models with axion-like particles, for two-Higgs-doublet models with a pseudo-scalar mediator between the Standard Model and the dark sector, for the invisible decay of the Higgs boson and for pair-produced weakly interacting dark matter candidates.

Combination of searches for Higgs boson decays into a photon and a massless dark photon using pp collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{\ extrm{s}} $$\\end{document}= 13 TeV with the ATLAS detector

A combination of searches for Higgs boson decays into a visible photon and a massless dark photon (H → γγd) is presented using 139 fb−1 of proton-proton collision data at a centre-of-mass energy of s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. The observed (expected) 95% confidence level upper limit on the Standard Model Higgs boson decay branching ratio is determined to be B\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{B} $$\\end{document}(H → γγd) < 1.3% (1.5)%. The search is also sensitive to higher-mass Higgs bosons decaying into the same final state. The observed (expected) 95% confidence level limit on the cross-section times branching ratio ranges from 16 fb (20 fb) for mH = 400 GeV to 1.0 fb (1.5 fb) for mH = 3 TeV. Results are also interpreted in the context of a minimal simplified model.

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The NEMO-3 results for the double-β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta $$\\end{document} decay of 150\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{150}$$\\end{document}Nd to the 01+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^+_1$$\\end{document} and 21+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^+_1$$\\end{document} excited states of 150\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{150}$$\\end{document}Sm are reported. 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The signal of the 2νββ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2\ u \\beta \\beta $$\\end{document} transition to the 01+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^+_1$$\\end{document} excited state is detected with a statistical significance exceeding 5σ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sigma $$\\end{document}. The half-life is measured to be T1/22νββ(01+)=1.11-0.14+0.19stat-0.15+0.17syst×1020\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{1/2}^{2\ u \\beta \\beta }(0^+_1) = \\left[ 1.11 ^{+0.19}_{-0.14} \\,\\left( \\hbox {stat}\\right) ^{+0.17}_{-0.15}\\,\\left( \\hbox {syst}\\right) \\right] \ imes 10^{20}$$\\end{document} year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the 2νββ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2\ u \\beta \\beta $$\\end{document} decay to the 21+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^+_1$$\\end{document} level the limit is T1/22νββ(21+)>2.42×1020year\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T^{2\ u \\beta \\beta }_{1/2}(2^+_1) > 2.42 \ imes 10^{20}~\\hbox {year}$$\\end{document}. The limits on the 0νββ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0\ u \\beta \\beta $$\\end{document} decay to the 01+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^+_1$$\\end{document} and 21+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^+_1$$\\end{document} levels of 150\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{150}$$\\end{document}Sm are significantly improved to T1/20νββ(01+)>1.36×1022year\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{1/2}^{0\ u \\beta \\beta }(0^+_1) > 1.36 \ imes 10^{22}~\\hbox {year}$$\\end{document} and T1/20νββ(21+)>1.26×1022year\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{1/2}^{0\ u \\beta \\beta }(2^+_1) > 1.26 \ imes 10^{22}~\\hbox {year}$$\\end{document}.

Search for an invisible scalar in tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} final states at the LHC

We use the current tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} experimental analysis to look for Dark Matter (DM) particles hidden in the final state. We present a phenomenological study where we successfully perform the reconstruction of a tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} system in the presence of a scalar mediator Y0, that couples to both Standard Model (SM) and to DM particles. We use a MadGraph5_aMC@NLO simplified DM model, where signal samples of pp →tt¯Y\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t}Y $$\\end{document}0 are generated at the Large Hadron Collider (LHC) with both Charge-Parity (CP) -even and CP-odd couplings of Y0 to the top quarks. Different mass scales for the Y0 mediator are considered, from the low mass region (~ 0 GeV) to masses close to the Higgs boson mass (125 GeV). The dileptonic final states of the tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} system were used in our analysis. The reconstruction of the tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} system is done with a kinematic fit, without reconstructing the mediator. All relevant SM backgrounds for the dileptonic tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} search at the LHC are considered. Furthermore, CP angular observables were used to probe the CP-nature of the coupling between the mediator and top-quarks, which allowed to set confidence level (CL) limits for those Yukawa couplings as a function of the mediator mass.

Health, environment, current knowledge of the heads of household and acute respiratory infection in toddlers

Background: The ten patrons of disease at the Moni Health Center, the highest acute respiratory infection (ARI) of all cases, the second highest ARI in toddlers (62.90%) in Ende District. ARI can inhibit oxygenation of the body, causing decreased cell metabolism, thereby inhibiting growth and development, can contribute to morbidity and mortality in infants. Toddlers are still fully cared for by the family, which is the front line to prevent toddlers from getting sick.Purpose: Determine the effect of knowledge and family home environment on the incidence of respiratory infections in toddlers.Method: The research design is a mix of methods and approaches cross sectional. The sample size was calculated based on the Slovin formula of 164 respondents. Sampling using purposive dan accidental sampling. Data collected by interview, observation. The instrument used is the standard instrument. Bivariate Analysis Who Square to examine the effect of family tasks on the incidence of ARI. Logistic regression test to analyze the strength of the influence of knowledge and family home environment on the incidence of ARI at the 95% confidence level and significance limit p ≤0,05.Results: Bivariate test increases the risk, namely family knowledge OR=1.950 (95% CI: 1.571-2.421; p=0.000), maintenance of the home environment, OR = 94.53 (95%) CI: 4.120 - 21.690p - value = 0.000 ), In the multivariate analysis, it was found that the most dominant variable influencing increased risk was the maintenance of the home environment. There is a need for periodic health counseling and promotion related to efforts to prevent and control ARI, further research needs to use other methods.Conclusion: The most dominant variable that influences increasing risk is the maintenance of the home environment. There is a need for periodic health counseling and promotion related to efforts to prevent and control respiratory infections, further research needs to use other methods.

Investigation of CO2 sequestration performance and statistical analysis of dye removal efficiency of liquefied hornbeam based carbon foams: Effects of biomass/solvent weight ratio, tar contribution, and chemical activation

Investigation of CO2 sequestration performance and statistical analysis of dye removal efficiency of liquefied hornbeam based carbon foams: Effects of biomass/solvent weight ratio, tar contribution, and chemical activation

Search for the production of dark matter candidates in association with heavy dimuon resonance using the CMS open data for proton–proton collisions at sqrt{s} = 8 TeV

In this work, we present a search for the possible production of Dark Matter particles at the Large Hadron Collider alongside a new hypothetical neutral gauge boson denoted by {Z}^{prime }. The topology of the studied events is dimuons plus large missing transverse momentum. The study is performed using the CMS open data samples collected by the CMS experiment in the LHC proton–proton collisions at center-of-mass energy of 8 TeV in 2012, which corresponds to an integrated luminosity of 11.6 hbox {fb}^{-1}, and the corresponding CMS open Monte Carlo samples. Two benchmark scenarios were used for interpreting the data, the Dark Higgs scenario and the effective field theory formalism. No evidence for the existence of dark matter candidates was found. 95% confidence level limits are set on the masses of the {Z}^{prime } and the cutoff scale of the effective field theory.

Search for Lorentz-invariance violation with the first KATRIN data

Some extensions of the Standard Model of particle physics allow for Lorentz invariance and charge-parity-time invariance violations. In the neutrino sector strong constraints have been set by neutrino-oscillation and time-of-flight experiments. However, some Lorentz-invariance-violating parameters are not accessible via these probes. In this work, we focus on the parameters (aof(3))00, (aof(3))10, and (aof(3))11 which would manifest themselves in a nonisotropic β-decaying source as a sidereal oscillation and an overall shift of the spectral endpoint. Based on the data of the first scientific run of the KATRIN experiment, we set the first 90% confidence-level limit on |(aof(3))11| of <0.9×10−6 GeV to 3.7×10−6 GeV, depending on the phase. Moreover, we derive new constraints on (aof(3))00 and (aof(3))10.Received 2 October 2022Revised 8 February 2023Accepted 14 March 2023DOI:https://doi.org/10.1103/PhysRevD.107.082005© 2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle astrophysicsPhysical SystemsNeutrinosPropertiesLorentz symmetryParticle propertiesTechniquesSpectroscopyParticles & FieldsGeneral PhysicsNuclear Physics

Prevalence of pre-diabetes and diabetes mellitus in Polycystic Ovarian Syndrome (PCOS)

Aim: To determine prevalence of pre-diabetes and diabetes mellitus in polycystic ovarian syndrome (PCOS) Study Design: Cross sectional study. Non probability consecutive sampling was done. Sample Size: The estimated sample size was 84 women with 95% confidence level and confidence limit of ±5%. Setting: Outpatient departments of Medicine and Gynaecology &amp; Obstetrics at a tertiary care hospital of Quetta, Pakistan. Period: January 2021 to October 2021. Methodology: All women of age 18-40 years who fulfilled the Rotterdam criteria of PCOS were included. Those having fasting blood sugar (FBS) ≥126mg/dl or 2 hour blood sugar &gt; 200 mg/dl on OGTT were said to have diabetes mellitus. Those having FBS between 100-125 mg/dl were said to have impaired fasting glucose (IFG) and those having 2 hour blood sugar between 141-199 mg/dl were said to have impaired glucose tolerance (IGT). Their age, BMI and Oral glucose tolerance test (OGTT) results were documented in the proforma. For analysis SPSS version 20 was used. Results: The mean age in our study was 29.12 ± 6.39 years and mean BMI was 30.49 ± 4.83 kg/m2. A screening OGTT revealed that 7.1 % of PCOS individuals have type 2 diabetes mellitus and 30.9 % had pre-diabetes (IFG, IGT). Conclusion: The prevalence of pre-diabetes and diabetes is high in PCOS, the main risk factor is increased BMI. Prevention and education should be undertaken in such individuals to avoid future complications. Key words: PCOS, Diabetes Mellitus, Developing Country

Development and validation of statistically sound criteria for the match of unweathered GC-MS fingerprints in oil spill forensics

The investigation of an oil spill's origin frequently relies on determining the equivalence of oil component patterns in samples from the contaminated environment and suspected oil source. This comparison benefits if based on the ratio of the abundance of unweathered characteristic components of the oil product, Diagnostic Ratios, DR. Replicate determinations of DR from one sample are used to set limits for the second sample's DR. The composition equivalence of oil patterns in both samples is indicated if all compared DR are statistically equivalent with a high confidence level. Some studies define DR limits assuming their normality and using Student's t statistics (S-t). However, since the ratio of correlated abundances can be not normally distributed, this criterion can drive to more false comparisons than predicted by the test confidence level. This work developed a computational tool for the reliable description of the non-normal distribution of the DR based on the Monte Carlo Method (MCM), aiming to allow the accurate control of the confidence of DR comparison. This work concluded that S-t defines 95% or 98% confidence limits with probabilities of falsely rejecting samples equivalence, φ, that can be up to 4.3% higher than predicted by the confidence level of the S-t test (i.e., 5% and 2%). The fragilities of the S-t limits significantly reduce the probability (1-θ) of two samples with the same oil producing equivalent values of all compared DR. For the studied 69 DR from unweathered components, the (1-θ) for 98% confidence level limits, set by the MCM and S-t from triplicate injections of one sample, are 94.8% and 91.7%, respectively. These values are below the confidence level (P) defined for each DR because DR are correlated with a correlation coefficient lower than 1. The (1-θ) can be increased to above P by using MCM limits and accepting composition equivalence if at least one of two sample extract injections produces values within limits set from the other sample's replicate injection. The validated user-friendly MS-Excel file used to set and access comparison criteria is made available as Supplementary Material and was checked experimentally. However, it is not feasible to estimate model confidence exclusively from experimentation because it would require too much independent analysis.

Probing small-scale baryon and dark matter isocurvature perturbations with cosmic microwave background anisotropies

The Universe's initial conditions, in particular baryon and cold dark matter (CDM) isocurvature perturbations, are poorly constrained on sub-Mpc scales. In this paper, we develop a new formalism to compute the effect of small-scale baryon perturbations on the mean free-electron abundance, thus on cosmic microwave background (CMB) anisotropies. Our framework can accommodate perturbations with arbitrary time and scale dependence. We apply this formalism to four different combinations of baryon and CDM isocurvature modes, and use Planck CMB-anisotropy data to probe their initial amplitude. We find that Planck data is consistent with no small-scale isocurvature perturbations, and that this additional ingredient does not help alleviate the Hubble tension. We set upper bounds to the dimensionless initial power spectrum $\Delta_{\mathcal{I}}^2(k)$ of these isocurvature modes at comoving wavenumbers $1~\textrm{Mpc}^{-1} \le k \le 10^3$ Mpc$^{-1}$, for several parameterizations. For a scale-invariant power spectrum, our 95% confidence-level limits on $\Delta_{\mathcal{I}}^2$ are 0.023 for pure baryon isocurvature, 0.099 for pure CDM isocurvature, 0.026 for compensated baryon-CDM perturbations, and 0.009 for joint baryon-CDM isocurvature perturbations. Using a Fisher analysis generalized to non-analytic parameter dependence, we forecast that a CMB Stage-4 experiment would be able to probe small-scale isocurvature perturbations with initial power 3 to 10 times smaller than Planck limits. The formalism introduced in this work is very general and can be used more widely to probe any physical processes or initial conditions sourcing small-scale baryon perturbations.

Search for dark matter produced in association with a single top quark in sqrt{s}=13\xa0TeV pp collisions with the ATLAS detector

This paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a, which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at sqrt{s} = 13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 hbox {fb}^{-1}. No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered.

Search for new phenomena in events with an energetic jet and missing transverse momentum in pp collisions at s=13 TeV with the ATLAS detector

Results of a search for new physics in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 139 fb$^{-1}$ at a center-of-mass energy of 13 TeV collected in the period 2015-2018 with the ATLAS detector at the Large Hadron Collider. Compared to previous publications, in addition to an increase of almost a factor of four in the data size, the analysis implements a number of improvements in the signal selection and the background determination leading to enhanced sensitivity. Events are required to have at least one jet with transverse momentum above 150 GeV and no reconstructed leptons ($e$, $\mu$ or $\tau$) or photons. Several signal regions are considered with increasing requirements on the missing transverse momentum starting at 200 GeV. Overall agreement is observed between the number of events in data and the Standard Model predictions. Model-independent 95 % confidence-level limits on visible cross sections for new processes are obtained in the range between 736 fb and 0.3 fb with increasing missing transverse momentum. Results are also translated into improved exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, supersymmetric particles in several compressed scenarios, axion-like particles, and new scalar particles in dark-energy-inspired models. In addition, the data are translated into bounds on the invisible branching ratio of the Higgs boson.

Search for invisible axion dark matter of mass ma=43 μeV with the QUAX– aγ experiment

A haloscope of the QUAX--$a\gamma$ experiment composed of an oxygen-free high thermal conductivity-Cu cavity inside an 8.1 T magnet and cooled to $\sim200$ mK is put in operation for the search of galactic axion with mass $m_a\simeq43~\mu\text{eV}$. The power emitted by the resonant cavity is amplified with a Josephson parametric amplifier whose noise fluctuations are at the standard quantum limit. With the data collected in about 1 h at the cavity frequency $\nu_c=10.40176$ GHz, the experiment reaches the sensitivity necessary for the detection of galactic QCD-axion, setting the $90\%$ confidence level limit to the axion-photon coupling $g_{a\gamma\gamma}<0.639\times10^{-13}$ GeV$^{-1}$.

Test of lepton flavor universality and search for lepton flavor violation in B \u2192 K\u2113\u2113 decays

We present measurements of the branching fractions for the decays B → Kμ+μ− and B → Ke+e−, and their ratio (RK), using a data sample of 711 fb−1 that contains 772 × 106 Boverline{B} events. The data were collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The ratio RK is measured in five bins of dilepton invariant-mass-squared (q2): q2 ∈ (0.1, 4.0), (4.00, 8.12), (1.0, 6.0), (10.2, 12.8) and (> 14.18) GeV2/c4, along with the whole q2 region. The RK value for q2 ∈ (1.0, 6.0) GeV2/c4 is {1.03}_{-0.24}^{+0.28} ± 0.01. The first and second uncertainties listed are statistical and systematic, respectively. All results for RK are consistent with Standard Model predictions. We also measure CP-averaged isospin asymmetries in the same q2 bins. The results are consistent with a null asymmetry, with the largest difference of 2.6 standard deviations occurring for the q2 ∈ (1.0, 6.0) GeV2/c4 bin in the mode with muon final states. The measured differential branching fractions, dmathrm{mathcal{B}} /dq2, are consistent with theoretical predictions for charged B decays, while the corresponding values are below the expectations for neutral B decays. We have also searched for lepton-flavor-violating B → Kμ±e∓ decays and set 90% confidence-level upper limits on the branching fraction in the range of 10−8 for B+ → K+μ±e∓, and B0 → K0μ±e∓ modes.

Search for dark matter in association with an energetic photon in pp collisions at sqrt{s} = 13 TeV with the ATLAS detector

A search for dark matter is conducted in final states containing a photon and missing transverse momentum in proton-proton collisions at sqrt{s} = 13 TeV. The data, collected during 2015–2018 by the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139 fb−1. No deviations from the predictions of the Standard Model are observed and 95% confidence-level upper limits between 2.45 fb and 0.5 fb are set on the visible cross section for contributions from physics beyond the Standard Model, in different ranges of the missing transverse momentum. The results are interpreted as 95% confidence-level limits in models where weakly interacting dark-matter candidates are pair-produced via an s-channel axial-vector or vector mediator. Dark-matter candidates with masses up to 415 (580) GeV are excluded for axial-vector (vector) mediators, while the maximum excluded mass of the mediator is 1460 (1470) GeV. In addition, the results are expressed in terms of 95% confidence-level limits on the parameters of a model with an axion-like particle produced in association with a photon, and are used to constrain the coupling gaZγ of an axion-like particle to the electroweak gauge bosons.

Search for phenomena beyond the Standard Model in events with large b-jet multiplicity using the ATLAS detector at the LHC

A search is presented for new phenomena in events characterised by high jet multiplicity, no leptons (electrons or muons), and four or more jets originating from the fragmentation of b-quarks (b-jets). The search uses 139~hbox {fb}^{-1} of sqrt{s} = 13 TeV proton–proton collision data collected by the ATLAS experiment at the Large Hadron Collider during Run 2. The dominant Standard Model background originates from multijet production and is estimated using a data-driven technique based on an extrapolation from events with low b-jet multiplicity to the high b-jet multiplicities used in the search. No significant excess over the Standard Model expectation is observed and 95% confidence-level limits that constrain simplified models of R-parity-violating supersymmetry are determined. The exclusion limits reach 950 GeV in top-squark mass in the models considered.

Search for direct production of electroweakinos in final states with missing transverse momentum and a Higgs boson decaying into photons in pp collisions at sqrt{s} = 13 TeV with the ATLAS detector

A search for a chargino-neutralino pair decaying via the 125 GeV Higgs boson into photons is presented. The study is based on the data collected between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 139 fb−1 of pp collisions at a centre-of-mass energy of 13 TeV. No significant excess over the expected background is observed. Upper limits at 95% confidence level for a massless {tilde{chi}}_1^0 are set on several electroweakino production cross-sections and the visible cross-section for beyond the Standard Model processes. In the context of simplified supersymmetric models, 95% confidence-level limits of up to 310 GeV in mleft({tilde{chi}}_1^{pm }/{tilde{chi}}_2^0right) , where mleft({tilde{chi}}_1^0right) = 0.5 GeV, are set. Limits at 95% confidence level are also set on the {tilde{chi}}_1^{pm }{tilde{chi}}_2^0 cross-section in the mass plane of mleft({tilde{chi}}_1^{pm }/{tilde{chi}}_2^0right) and mleft({tilde{chi}}_1^0right) , and on scenarios with gravitino as the lightest supersymmetric particle. Upper limits at the 95% confidence-level are set on the higgsino production cross-section. Higgsino masses below 380 GeV are excluded for the case of the higgsino fully decaying into a Higgs boson and a gravitino.

A search for dark matter in Triangulum II with the MAGIC telescopes

We present the first results from very-high-energy observations of the dwarf spheroidal satellite candidate Triangulum II with the MAGIC telescopes from 62.4 hours of good-quality data taken between August 2016 and August 2017. We find no gamma-ray excess in the direction of Triangulum II, and upper limits on both the differential and integral gamma-ray flux are presented. Currently, the kinematics of Triangulum II are affected by large uncertainties leading to a bias in the determination of the properties of its dark matter halo. Using a scaling relation between the annihilation J-factor and heliocentric distance of well-known dwarf spheroidal galaxies, we estimate an annihilation J-factor for Triangulum II for WIMP dark matter of $\log[J_{\text{ann}}({0.5^{\circ}})/$ GeV$^{2}$ cm$^{-5}] = 19.35 \pm 0.37$. We also derive a dark matter density profile for the object relying on results from resolved simulations of Milky Way sized dark matter halos. We obtain 95% confidence-level limits on the thermally averaged annihilation cross section for WIMP annihilation into various Standard Model channels. The most stringent limits are obtained in the $\tau^{+}\tau^{-}$ final state, where a cross section for annihilation down to $\langle \sigma_{\text{ann}} v \rangle = 3.05 \times 10^{-24}$ cm$^{3}$ s$^{-1}$ is excluded.